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ANSYS ICEM CFD Tutorial Manual

1. Step 8 Verify and Save the Mesh and Blocking 1 Convert the mesh to unstructured format Blocking RvB pre Mesh Convert to Unstruct Mesh Save the blocking file 2 2D pipe geometry final b1k File gt Blocking gt Save Blocking As This block file can be loaded in a future session File gt Blocking gt Open Blocking for additional modification or to mesh a similar geometry Save each blocking to a separate file instead of overwriting a previous one In more complex models you may have to back track and load a previous blocking Save the project file 2 D pipe geometry final prj File gt Save Project As This will save all the files tetin blocking and unstructured mesh Exit the current session File gt Exit ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 29 30 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Hexa Mesh Generation for a 2D Car In this tutorial you will generate a Mesh for external flow over a simple 2D Car residing in a wind tunnel Replay Control will be employed for recording all the blocking steps This replay script file will be run to block and mesh a modified geometry The 2D Car geometry is shown Figure 21 2D Car G
2. Multizone Meshing is able to capture the details and by starting with a Patch based Surface Topology many of the processes can be automated This is the preferred method for this geometry and will be de scribed here 1 Establish surface patches and connectivity Geometry gt Repair Geometry B Build Diagnostic Topology A a Use the default tolerance 0 003 b Click Apply Figure 230 Build Diagnostic Topology on HVAC Transition Duct Note Wide Red curves indicate connectivity between surface patches Connectivity between adjacent surface patches is important when creating the surface blocking Check the model carefully for holes and unconnected surfaces indicated by yellow curves and repair if necessary 2 Set Global Mesh Parameters Mesh gt Global Mesh Setup Kia gt Global Mesh Size B ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 307 Multizone Mesh in HVAC Square to circle Transistion Duct a Set Max element value to 0 8 b Click Apply 3 Set Mesh Parameters by Part Mesh gt Part Mesh Setup we a Set parameters as shown in the graphic Figure 231 Part Mesh Setup for HVAC Transition Duct G Part Mesh Setup SQUARE IV Show size params using scale factor Apply inflation parameters to curves Remove inflation parameters from curves b Click Apply
3. Yes No Re mesh out of date parts Re mesh specific parts d Disable Surfaces and Edges Geometry Surfaces Blocking Edges e Select Solid amp Wire Blocking Pre Mesh Solid amp Wire The initial mesh is shown in Figure 57 Initial Mesh p 78 Figure 57 Initial Mesh ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 78 formation of ANSYS Inc and its subsidiaries and affiliates Step 7 Checking the Mesh Quality Step 7 Checking the Mesh Quality The major quality criteria for a hexa mesh are angle determinant and warpage Refer to the Help Manual for details on the available quality measures Blocking gt Pre Mesh Quality Histograms Pre Mesh Quality Criterion Angle x Min overview Histogram Options Min value boon Max value 90 Max Y height 20 Num of bars 20 kel ale Only visible index range I Active parts only Apply Dismiss 1 Select Angle in the Criterion drop down list 2 Retain the default settings for Histogram Options and click Apply 3 Select the worst two bars from the histogram The selected bars will be highlighted in pink Figure 58 Histogram of Angle p 79 Figure 58 Histogram of Angle 24 18 4 Right click in the histogram window and ensure that Show is enabled 5 Disable Pre Mesh Blocking Pre Mesh The highlighted elements are shown Figure
4. ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 129 Hexa Mesh Generation for a Pipe with Embedded Blade 5 Click Apply This will compute the node distributions on the blocking edges from the surface parameters Enable the Pre Mesh display from the Display Tree Allow recompute when prompted Blocking Pre Mesh Enable Solid amp Wire in the Display tree for better visualization See Figure 96 Initial Mesh on Outlet surface p 130 Blocking Pre Mesh Solid amp Wire Figure 96 Initial Mesh on Outlet surface The mesh is denser at the walls The near wall elements will have the same initial height that was set on the surface parameters which was 0 03 Defining Edge Parameters to Adjust the Mesh Although it may be enough to define the meshing with surface parameters the mesh quality of more complex models can be improved by defining additional edge parameters Perform these next steps to redistribute points along the diagonal radial edge of the O grid Blocking gt Pre Mesh Params amp gt Edge Params TR 1 Disable Pre Mesh in the Display tree This will allow changes without requiring Mesh recompute at every step and allow edges to be easily seen and selected In the Display tree enable the display of Vertices and then enable display of vertex Numbers 130 ANSYS ICEM CFD 14 5
5. Note If you right click on Pre Mesh in the Display tree you should see Project faces is checked On default ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 132 formation of ANSYS Inc and its subsidiaries and affiliates Checking and Improving Mesh Quality 8 In the Display tree disable the display of the SOLID part The final mesh should appear similar to Fig ure 99 Final Mesh p 133 Your colors may vary and may be changed by right clicking on a Part name in the Display tree Figure 99 Final Mesh Checking and Improving Mesh Quality 1 Check mesh quality Blocking gt Pre mesh Quality Histogram 2 In the Criterion drop down list select Determinant 2x2x2 Enter the Min X value 0 Max X value 1 Max Y height 12 and Num of bars 20 Check the Active Parts only is selected 3 Press Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 133 Hexa Mesh Generation for a Pipe with Embedded Blade Figure 100 Determinant 2x2x2 Quality Histogram Determinant 2x2x2 Note A value of determinant greater than 0 2 is acceptable for most commercial solvers In the Criterion drop down list change the selection to Angle Enter the Min X value 0 Max X value 90 Max Y height 12 and Num of bars 18 Press Ap
6. The Select geometry toolbar will appear c Disable Toggle selection of points x Toggle selection of curves x and Toggle selection of bodies 8 material region definition to avoid the selection of entities other than surfaces d Ensure that Toggle selection of surfaces is enabled Note Entity types can also be deactivated by disabling them in the display control tree e Select the largest semi cylinder and click the middle mouse button to accept the selection f Click Apply in the Create Part DEZ The new part CYL1 will be added to the display control tree Similarly create new parts for the smaller semi cylinder CYL2 cylinder ends INL and OUT and symmetry planes SYM as shown in Figure 49 3D Pipe Geometry Surface Parts p 66 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 65 Hexa Mesh Generation for a 3D Pipe Junction Figure 49 3D Pipe Geometry Surface Parts Note When in continuation mode with Auto Pick Mode enabled after pressing the middle mouse button or Apply you can type in a new Part name and continue to select the surface s without re invoking the function 4 Create a new part comprising all the curves in the geometry a Enter CURVES for Part in the Create Part DEZ b Retain the selection of Nx Create Part by Selection and click R
7. 4 Smooth the mesh ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 282 formation of ANSYS Inc and its subsidiaries and affiliates Step 5 Saving the Project As the prisms were smoothed in the previous step you will smooth the other elements without adjusting the prisms Edit Mesh gt Smooth Mesh Globally a Enter 20 for Smoothing iterations and 0 2 for Up to value b Retain the selection of Quality in the Criterion drop down list c Select Freeze for PENTA_6 d Retain the other settings and click Apply The quality histogram will be updated Check the mesh for any errors that may cause problems during the analysis Edit Mesh gt Check Mesh Step 5 Saving the Project 1 Save the geometry and mesh File gt Save Project As Select the solver Output gt Select solver gt Solver Setup P Output Solver ANSY S Fluent zx Common astran S S SYd Structural Solver I Set As Default Apply ERs Dismiss a Select ANSYS Fluent from the Output Solver drop down list b Retain NASTRAN in the Common Structural Solver drop down list c Click Apply Set the appropriate boundary conditions ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 283 Tetra Prism Mesh Generation for an Aorta Output gt B
8. For Mesh Type select Tetra Mixed from the drop down list For Mesh Method select Robust Octree from the drop down list For Select Geometry select All from the drop down list Click Compute to generate the mesh 292 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Generating the Tetra Mesh in CYL2 Figure 216 Tetra Mesh in CYL1 Region Created es PES SPSS AY NG ae SS VANES ASAE tA s BES d Z ER ENS Ers ans Dg A ius K KAA RI NZ ASS TETARA ities AE FON iat Mie mata EA va AVES i gt 2 a ne mew f f f 3 Save the mesh data File gt Mesh gt Save Mesh As a Choose an appropriate name for example Cy11_Tetra_Mesh uns b Close the mesh data file File gt Mesh gt Close Mesh Generating the Tetra Mesh in CYL2 The Material point will be moved to the CYL2 region where a Tetra mesh will be generated 1 Move the Material point Geometry gt Transform Geometry amp gt Translate Geometry Pag a Click Select geometry and then click on the LIVE1 body point b Click the middle mouse button to accept c For Method choose Explicit from the drop down list d For X Offset enter a value of 25 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliate
9. gt Set Location 4x12 182 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Associate Initial Blocking to a Minor Geometry Move Yertices Move Yertices PHR aN Z Set Location Method Set Position v Reference From Vertex C Screen Ref Vertex p 19 ae Set Coordinate system Catesian M ModityX X tempx Modityy Y itemy M ModityZ z temz Modify Normal Normal g Vertices to Set p 13 T m zl Apply IL o Dismiss i Ensure Method is Set Position and Reference From is Vertex ii For Ref Vertex click Select vert s and then select Vertex 19 You may find it useful to disable the display of points while performing this sequence iii Ensure only Modify X is selected in the Set area iv For Vertices to Set click Select vert s and then select Vertex 13 v Click the middle mouse button to accept your selection vi Click Apply Vertex 13 moves into x direction alignment with vertex 19 which is the center of the curve ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 183 Bottom Up Hexa Mesh Strategy for a Grid Fin Figure 142 Initial Block associated to minor Geometry With Curves disabled Red vertices 11 19
10. 3 represents the radial O Grid direction In this model I J K is more or less lined up with the global X Y Z coordinates respectively b Increase the Grid Index for the 0 index plane until the scan plane appears about half way through the model Note When you increase the Grid Index two planes will be visible at the same time Along the radial O Grid block is equal to 1 throughout the entire block c Click Select in the scan plane control window d Select one of the edges parallel to the current scan plane an edge lined up along Y See Fig ure 78 Scan Planes for the Mesh p 107 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 106 formation of ANSYS Inc and its subsidiaries and affiliates Step 10 Verifying and Saving the Mesh Figure 78 Scan Planes for the Mesh ars fs wh ig i Milas is i A na N i iiS A na miT Note The Select option enables the index plane perpendicular to any selected edge In this case the edge selected is a J edge and the resulting scan plane will be perpen dicular to that edge and will display constant J nodes The index plane 1 is automatically enabled in the scan plane control window e Continue to select and switch back and forth through the other planes as well f Click Done to exit the scan plane control window Step 10 Verifying and Saving the Mesh 1 Check the mesh quality
11. SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Defining Edge Parameters to Adjust the Mesh 3 Click amp Select edge s and then select one of the Radial Edges of the O grid See Figure 97 Select Radial Edge of the O grid p 131 Figure 97 Select Radial Edge of the O grid 4 Set Spacing 1 to 0 015 which is half of the previous value Also set Spacing 2 to 0 which will allow it to go as large as is needed and Nodes to 13 which will allow Ratio 1 1 25 to be met 5 Enable Copy Parameters and then select To All Parallel Edges from the Copy drop down list 6 Click Apply Note In the Display tree enable the display of Bunching Blocking Edges Bunching ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 131 Hexa Mesh Generation for a Pipe with Embedded Blade Figure 98 Edge Parameter Bunching Spacing 1 is the first element size at start of the edge vertex 134 and Spacing 2 is the last element size at the finish end vertex 200 Start and Finish are identified by the direction arrow that displays on the edge The small quads give a visual indication of the mesh size at that point Disable the Bunching display 7 In the Display tree enable Pre Mesh Allow Recompute when prompted
12. h Click Apply i Click a Select edge s and then select edge 49 50 horizontal edge behind the car at roof level j Set the number of Nodes to 75 and enter 1 2 for Ratio1 and Ratio2 k Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 49 Hexa Mesh Generation for a 2D Car Enable Pre Mesh in the Display Tree and recompute See Figure 37 Cartesian grid after Edge Parameters p 50 Figure 37 Cartesian grid after Edge Parameters Ni Mt NTT wt nan it Hi pede IMA Ait Hh ttt HN Aun iit niet TTT Hoan RG a at Create an O grid In this step you will create an O Grid where the mesh radially propagates from the surface of the car towards the outer domain This will result in an orthogonal mesh to better capture near wall or boundary layer flow 1 Disable Pre Mesh 2 Enable the VORFN part to enable you to select the interior blocks Parts VORFN 3 Create an O Grid around the car Blocking gt Split Block gt Ogrid Block A a Click R select block s b Select the blocks inside the car and below the car as shown in Figure 38 Blocks for O grid p 51 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 50 formation of ANSYS Inc and its subsidiaries and affiliates C d e f Figure 38 Block
13. ib p B a Fluid Dynamics Structural Mechanics Electromagnetics Systems and Multiphysics ANSYS ICEM CFD Tutorial Manual ANSYS Inc ANSYS ICEM CFD 14 5 Southpointe October 2012 275 Technology Drive Canonsburg PA 15317 ANSYS Inc is ansysinfo ansys com certified to ISO http www ansys com 9001 2008 T 724 746 3304 F 724 514 9494 Copyright and Trademark Information 2012 SAS IP Inc All rights reserved Unauthorized use distribution or duplication is prohibited ANSYS ANSYS Workbench Ansoft AUTODYN EKM Engineering Knowledge Manager CFX FLUENT HFSS and any and all ANSYS Inc brand product service and feature names logos and slogans are registered trademarks or trademarks of ANSYS Inc or its subsidiaries in the United States or other countries ICEM CFD is a trademark used by ANSYS Inc under license CFX is a trademark of Sony Corporation in Japan All other brand product service and feature names or trademarks are the property of their respective owners Disclaimer Notice THIS ANSYS SOFTWARE PRODUCT AND PROGRAM DOCUMENTATION INCLUDE TRADE SECRETS AND ARE CONFID ENTIAL AND PROPRIETARY PRODUCTS OF ANSYS INC ITS SUBSIDIARIES OR LICENSORS The software products and documentation are furnished by ANSYS Inc its subsidiaries or affiliates under a software license agreement that contains provisions concerning non disclosure copying length and nature of use compliance with exporting
14. A VN a V VALL V BOY WAIT N YAN A V lt lt T a LX AO VT VAN F a 7 Y A Va NNV A O SO Fo N a O T v XZ WA l Z Was VA x yY RAVE AVAD AAAY TALE A AN NY VX VN Further splits to define the Hub part a Set the Index control values as shown in the following table Blocking EB gt index Control 196 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Refine the Blocking with Further Splits and Associations In the Split Block by Prescribed point DEZ click Select edge s and then the edge intersecting point POINTS 15 as shown in Figure 153 POINTS 15 and Edge for First Hub Split p 197 Figure 153 POINTS 15 and Edge for First Hub Split Click amp Select point s and then select the point POINTS 15 Click Apply Similarly create a split passing through point POINTS 16 perpendicular to the edge as shown in Figure 154 POINTS 16 and Edge for Second Hub Split p 198 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 197 Bottom Up Hexa Mesh Strategy for a Grid Fin Figure 154 POINTS 16 and Edge for Second Hub Split Select Edge 3 In the Display tree enable Blo
15. Blocking gt Pre Mesh Quality Histograms If you are satisfied with the mesh quality convert the existing mesh to an unstructured mesh Save the mesh in unstructured format Blocking Pre Mesh Convert to Unstruct Mesh This saves the uns file as the mesh in the working directory and automatically loads it Save the blocking file sphere cube final b1k File gt Blocking gt Save Blocking As ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 107 Hexa Mesh Generation for a Sphere Cube Geometry 4 Save the project file sphere cube final pr 4 File gt Save Project As 5 Exit the current session File gt Exit ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 108 formation of ANSYS Inc and its subsidiaries and affiliates Hexa Mesh Generation for a Pipe with Embedded Blade In this tutorial you will use the Collapse function to create a degenerate topology in a Conjugate Heat transfer problem around a blade located in the center of a cylindrical pipe The Pipe Blade geometry is shown Figure 79 Pipe Blade Geometry This tutorial demonstrates how to do the following Starting the Project Creating Parts in the Mesh Editor Starting Blocking and Fitting it to the Geometry Splitting and Collapsing Blocks around the B
16. 25 Blocking e pre Mesh 24 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 7 Match the Edges Figure 16 Refined Mesh a gt SZ ca LZ 2 ARA L2 tara oa LF GOLD ea 23 Z sss SSS Oe ee 1 K po 5 aan on Sven Step 7 Match the Edges In this step you will match the edge spacing of a Reference Edge to the connecting Target Edge s The node spacing on the end of your selected target edge will be modified to match the node spacing on the reference edge Blocking gt Pre Mesh Params gt Match Edges 1 1 Match the edge spacing manually Pre Mesh Params Q Meshing Parameters A P Match Edge spacing Method Selected x Reference Edge a2 43 1 amp PE Target Edge s i 41 42 1 32 amp ee Link spacing z Apply Lo Dismiss a Retain Selected in the Method drop down list ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 25 Hexa Mesh Generation for a 2D Pipe Junction b Click Select edge s for Reference Edge select edge 42 43 c Click a Select edge s for Target Edge s select edges 41 42 and 42 33 and click the middle mouse button to accept the selection d Cli
17. Click Apply e Recompute the mesh Figure 134 Pre Mesh After Modifying Edge Parameters Before Adjusting After Adjusting Edge Parameters Edge Parameters In Figure 134 Pre Mesh After Modifying Edge Parameters p 166 the distribution on the edges is much smoother now However there still is a slight jump around the center where the mesh size is considerably larger You will use match edges to improve the mesh distribution ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 166 formation of ANSYS Inc and its subsidiaries and affiliates 3 4 Step 8 Generating the Mesh Match the inward edges and outward edges to correct the jump in the midsection Blocking gt Pre Mesh Params gt Match Edges I a Select the Reference Edge and Target Edge as shown in Figure 135 Edges Selected for Match Edges p 167 Figure 135 Edges Selected for Match Edges reference edge This will match the end spacing of the outer reference edge to the end spacing of the inner target edge But only the selected radial edge is matched You have to copy this to all the other edges b Recompute the mesh c Copy the spacing to all the other edges Blocking gt Pre Mesh Params Edge Params i i Click Select edge s and select the matched edge ii Ensure Copy Parameters is enabled and To All Parallel Edges is selected in the Method list iii Click Apply iv Recompu
18. Delaunay from the Mesh Method drop down list b Enter 1 2 for Spacing Scaling Factor c Click Apply 2 Compute the mesh Mesh gt Compute Mesh gt Volume Mesh M Compute Mesh a Compute a EAZ Yolume Mesh Mesh Type Tetra Mixed Dd Tetra Mixed Mesh Mesh Method Quick Delaunay yi F Create Prism Layers F Create Hexa Core Volume Part Name inherited Select Existing Mesh x V Load mesh after completion 3 Compute Loi Dismiss ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 260 formation of ANSYS Inc and its subsidiaries and affiliates Step 4 Generating the Delaunay Mesh Select Quick Delaunay from the Mesh Method drop down list Disable Create Prism Layers Ensure that Existing Mesh is selected in the Select drop down list Enable Load mesh after completion Click Compute The progress will be reported in the message window Examine the mesh Figure 200 Cut Plane in Z Direction for Delaunay Mesh p 261 a Select Solid amp Wire Mesh Shells Solid amp Wire Examine the mesh using a cut plane Figure 200 Cut Plane in Z Direction for Delaunay Mesh p 261 and Figure 201 Zoomed in Cut Plane in Wake Region for Delaunay Mesh p 262 show the cut planes for Delaunay mesh Figure 200 Cut Plane in Z Direction for Delaunay Mesh ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserve
19. Disable FF in the display control tree Parts FF Select Solid amp Wire Mesh Shells Solid amp Wire Figure 196 Octree Mesh for Helicopter Figure 196 Octree Mesh for Helicopter p 256 shows the Octree mesh The various colors help illus trate the patch independence View the wake region and examine the prism layers The prism height floats as the height was initially set to zero The variation in layer thickness float is not significant for this model because the surface mesh size is relatively uniform You may try with different mesh sizes or with curvature based refinement for greater effect Figure 197 Zoomed in Mesh Slivers Meshed with Equilateral Triangles p 257 shows the zoomed in slivers meshed with equilateral triangles 256 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Generating the Octree Mesh Figure 197 Zoomed in Mesh Slivers Meshed with Equilateral Triangles Note Some solvers may not like the volume transitions in the Octree mesh Step 4 explains how you can replace the Octree volume mesh with a Delaunay volume mesh for smoother volume transition Use a cut plane to examine the mesh a Select Wire Frame Mesh Shells Wire Frame Select Manage Cut Plane Mesh Cut Plane Manage Cut Plane Set the following parameters i Select by C
20. Enable ELBOW_1_1 in the display tree 7 Click Reset in the Index Control window ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 157 Hexa Mesh Generation for an Elbow Part Step 6 Generate the Pre Mesh 1 Update the mesh sizes Blocking gt Pre Mesh Params Update Sizes a Ensure that Update All is selected for Method b Select Run Check Fix Blocks c Click Apply 2 Enable Pre Mesh Blocking Pre Mesh The Mesh dialog box will appear asking if you want to recompute the mesh Click Yes m 3 Examine the quality Blocking gt Pre Mesh Quality Histogram a Disable SOLID in the display tree Parts SOLID b Ensure that Determinant 2x2x2 is selected in the Criterion drop down list c Retain the values of 0 for Min X and 1 for Max X d Retain the values of 0 for Max Y height and 20 for Number of bars e Ensure that Only visible index range is disabled f Enable Active parts only g Click Apply Figure 124 Pre Mesh Quality Histogram p 158 Figure 124 Pre Mesh Quality Histogram Determinant 2x2x2 h Select the lower value bars lt 0 6 to see the skewed cells Figure 125 Skewed Cells Below 0 6 in the Pre Mesh p 159 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 158 formation of ANSYS Inc and its subs
21. For Up to quality enter a value of 0 4 c For Criterion select Quality from the drop down list d Click Apply Figure 228 Quality Histogram after Smoothing 0 I l 0 0 1 0 2 0 3 Save the complete mesh in a new file File gt Mesh gt Save Mesh As a Select a suitable file name for example merged_mesh_domain uns b Click Apply Exit saving the project on the way out File gt Exit ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 303 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 304 formation of ANSYS Inc and its subsidiaries and affiliates Multizone Mesh in HVAC Square to circle Transistion Duct In this tutorial example you will use the ANSYS ICEM CFD MultiZone meshing method to automatically hybrid mesh a section of HVAC duct This mesher is ideal for situations where a high quality boundary layer mesh is needed but it would be difficult to lay out a structured grid to fill the volume It is particularly designed for external aerody namics where the boundary layer is critical and the volume around it can be very complicated The MultiZone process starts with surface blocking extracted from the geometry topology and then extrudes sweeps these blocks into the volume to create the high quality boundary
22. For the Maximum size enter 4 Leave all other default values Click Apply Set Surface Mesh parameters on the fin surfaces a Still in the Surface Mesh Setup DEZ click B Select surface s 2 In the Select geometry popup toolbar click 4 Select items in a part In the Select part dialog box select LEAD TRAIL PRESS SUCT and TIP Click Accept For the Maximum size enter 1 Leave all other default values Click Apply Set Curve Mesh parameters Mesh gt Curve Mesh Setup AL Note All curves are in the GEOM part Click amp Select curve s 2 In the Select geometry popup toolbar click 4 Select items in a part In the Select part dialog box select GEOM and then click Accept For the Maximum size enter 0 Leave all other default values If the Maximum size is set to 0 this effectively unsets the curve maximum size allowing adjacent surface sizes alone to control the mesh 222 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Setup Mesh Parameters Click Apply Create Mesh Density regions at the leading and trailing surfaces of the fin A density region allows you to set a local maximum size within a portion of the volume This is useful for locally increasing refinement to better capture flow details without needing to refine the entire mesh Mesh gt Create Mesh D
23. Inc and its subsidiaries and affiliates Step 1 Creating Parts Step 1 Creating Parts The imported geometry comprises a single part You will split the geometry and define the parts in this step 1 Split the geometry Geometry gt Create Modify Surface e gt Segment Trim Surface i Create Modify Surface 7 jeo O OA F FUG sosa Method By Angle xj Faceted Surface AOR eB EEP Angle 35 Minimum number of segments fi F Keep original Apply Dismiss a Select By Angle from the Method drop down list zl b Click a Select surface s and select the aorta surface Click the middle mouse button to accept the selection c Enter 35 for Angle and click Apply 2 Create the INLET part e parts be create Part a Enter INLET for Part in the Create Part DEZ b Retain the selection of Nx Create Part by Selection and click S Select entities The Select geometry toolbar will appear c Select the inlet surface Figure 205 Aorta Parts p 268 and click the middle mouse button to accept the selection ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 267 Tetra Prism Mesh Generation for an Aorta d Click Apply 3 Create the OUTLET part a Enter OUTLET for Part in the Create Part DEZ b Click x Select entities and select the outlet surfaces
24. Multizone Mesh in HVAC Square to circle Transistion Duct Figure 229 Geometry for HVAC Transition Duct Surfaces have been enabled in the Display tree Note If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Throughout this and other tutorials Parts Points Curves and Surfaces may be made visible or turned off as necessary to assist in describing the steps of the tutorial Typically the default settings for visibility are sufficient for most work and such steps are used only to isolate spe cific parts for specific tasks Set up Global and Part Parameters There are a few options for meshing this duct using ICEM CFD Each has its advantages and disadvantages e Tetra Prism This is automated and has good feature capture ability but is slower and less efficient in most solvers Body Fitted Cartesian Also automated but has low feature capture and boundary resolution e Hexa Can be made to capture all the details but the blocking may require an experienced user ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 306 formation of ANSYS Inc and its subsidiaries and affiliates Set up Global and Part Parameters
25. SAS IP Inc All rights reserved Contains proprietary and confidential in 148 formation of ANSYS Inc and its subsidiaries and affiliates Step 4 Creating the First O Grid a Click Select block s and select the 2 blocks shown in Figure 114 Blocks and Faces Selected for the First O Grid p 149 Click the middle mouse button to finish the selection b Click Select face s and select the faces shown in Figure 114 Blocks and Faces Selected for the First O Grid p 149 Click the middle mouse button to finish the selection The cylinder will now pass through the top and bottom of the geometry Figure 114 Blocks and Faces Selected for the First O Grid c Click Apply to create the first O Grid After creating the first O Grid the blocking will appear as shown in Figure 115 First O Grid p 149 Figure 115 First O Grid 2 Assign the material inside the cylinder to the SOLID part ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 149 Hexa Mesh Generation for an Elbow Part This will remove this region from the mesh if it is computed with the SOLID part disabled Blocking Index Control The index control window will appear in the lower right corner Change the Min for O3 from 0 to 1 D You can click the up arrow or type the number and click the enter key on the keyboard You should then
26. SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 113 Hexa Mesh Generation for a Pipe with Embedded Blade 6 Delete any Empty Parts RMB I gt Parts Delete Empty Parts 7 Save the updated model before continuing on in this tutorial File gt Save Project Initial Blocking and Associations The blocking strategy for this model involves an internal O Grid longitudinally in the pipe surrounding sep arate blocking for the blade Within the ANSYS ICEM CFD projection based mesh generation environment the block faces between different materials at the Fluid Solid interface are projected to the closest geometry surface Block faces within the same material may be associated to specific CAD surfaces only if necessary for the definition of internal walls Here you create the initial blocking and then fit the blocking more closely to the geometry by associ ating the vertices and edges to the geometry 1 Initialize the blocking p Blocking gt Create Block gZ gt Initialize Blocks g Create Block P Part FLUID S P Inherit Part Name Create Block Initialize Blocks Type 30 Bounding Box x Entities peste Project vertices F Orient with geometry 2D Blocking IW Initialize with settings al Amy Dismiss a Ensure that Part is set to the correct material FLUID b Retain the selection of 3D Bou
27. a multigrid mesh will be generated A multigrid mesh restricts the number of elements on an edge to be divisible by a power of two That is for a given multigrid level M the number of elements must be an integer multiple of 2 M thus the number of nodes will be N 24M 1 For example for multigrid level 2 the number of nodes on an edge will be 5 9 13 17 or similar The actual number will be a function of the geometry and allowable maximum mesh size 1 Define the meshing multigrid parameters Settings gt Meshing Options gt Hexa Meshing a Enter 2 for Multigrid level ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 209 Bottom Up Hexa Mesh Strategy for a Grid Fin b Retain the other default settings c Click Apply 2 Set the surface mesh size Mesh gt Surface Mesh Setup e a Click B Select surface s b Click x Select all Alternatively press a to select all c Set the Maximum size to 0 4 the Height to 0 4 and the Height ratio to 1 2 d Click Apply 3 Update Sizes Blocking gt Pre Mesh Params Update Sizes a Ensure Update All is selected This will automatically determine the number of nodes on the edges from the surface mesh sizes and multigrid level b Click Apply 4 Compute and display the Mesh Blocking e pre mesh Allow re compute when prompted ANSYS
28. and its subsidiaries and affiliates Splitting and Collapsing Blocks around the Blade Figure 87 X direction Splits 5 Collapse Blocks to display the Blade In this sequence the Collapse feature is introduced to create degenerate blocks for the blade a Before collapsing the blocks the two center blocks representing the Blade should be assigned to the part SOLID Parts SOLID Add to Part Select G Blocking Material Add Blocks to Part ii Click amp Select block s and then select the two blocks of the Blade iii Click the middle mouse button to accept iv Click Apply The blocks will change color to match SOLID as seen in the Display tree Use Index Control to isolate the visible blocks Blocking Index Control Change the Index control for the I dimension to 2 3 Note Every time a block Split is performed the Index control is updated After the splits are complete the full range of the I dimension will be from 0 5 Reducing this to 2 3 displays only the center blocks longitudinally in the pipe including the blade ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 121 Hexa Mesh Generation for a Pipe with Embedded Blade c Now open the Merge Vertices DEZ i w Blocking gt Merge Vertices 4 gt Collapse Blocks d Click Ss Select edge s and then choose the edge tha
29. side meet at less than the specified angle If the surfaces curves meet at greater than the specified angle the feature curve point remains Since Octree Tetra forces the mesh to respect curves and points removing unnecessary ones increases the patch independence and mesh quality 234 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Defining the Parts d Click Apply Figure 182 Build Diagnostic Topology applied to Piston Valve Geometry After Filter Curves and Points Note If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Throughout this and other tutorials Parts Points Curves and Surfaces may be made visible or turned off as necessary to assist in describing the steps of the tutorial Typically the default settings for visibility are sufficient for most work and such steps are used only to isolate spe cific parts for specific tasks Defining the Parts Initially the geometry file described only surfaces Build Topology was used to create curves and points from the surface intersections Now parts will be defined to contain the geomet
30. 1 Display the internal mesh structure Pre Mesh Cut plane Disable Pre Mesh in the Display tree a In the Method drop down list select Middle Z Plane ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 313 Multizone Mesh in HVAC Square to circle Transistion Duct Figure 235 Longitudinal Cut plane view in HVAC Transition Duct From the menu bar choose View gt Front Note Both end zones contain Hexa elements automatically mapped during the 2D to 3D fill process The middle zone is Tetra Mesh indicating it is unstructured b In the Method drop down list select Middle Y Plane ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 314 formation of ANSYS Inc and its subsidiaries and affiliates Checking the Mesh Saving and Exiting Figure 236 Cross Sectional Cut plane view in HVAC Transition Duct View gt Top Note The structured boundary layer hexa mesh near the surface is created because of Ogrid blocking c Use the scroll wheel to move the cut plane along the duct geometry Observe the hexa mesh at the extents of the duct orthogonal blocking structure and the ir regular tetra mesh in the center of the duct transition region 2 Change the Display to do manual quality improvement a Dismiss the Cut Plane Pre Mesh
31. 180 195 21 111 210 211 21 89 210 89 65 228 65 136 245 Figure 150 Complete 2D blocking Extrude a 2D Planar Grid to Create 3D Blocking The Complete 2D grid will be positioned in a single plane at the boundary of the geometry and then extruded in the Z direction through the extent of the geometry In the Display tree disable the display of Points for this sequence 1 Move all vertices to one plane at the bottom of the geometry Blocking gt Move Vertex F gt Set Location 4x12 a Under Set ensure that only Modify Z is checked ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 193 Bottom Up Hexa Mesh Strategy for a Grid Fin b Enter 5 for Z c For Vertices to Set click R Select vert s d Select all vertices i Use a box selection ii Click the middle mouse button to apply Alternatively click 0 Select all appropriate visible objects e Click Apply The complete topology is moved to Z 5 plane 2 Extrude to create 3D blocking Z Blocking gt Create Block gZ gt 2D to 3D a From the Method drop down list select Translate b For Z Distance enter 5 c Click Apply The 3D blocking after extrusion is shown in Figure 151 Initial 3D Blocking after Extrusion p 195 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains p
32. Adjust the O Grid Edge Length to Improve Quality Figure 119 Vertices Projected to the Cylinder T TF A i OOZ 2a oe ae aa re eal AN f i gt lt f lt i pA d 5 N ii atin ka pr h N A paa P Improve the placement of the vertices on the cylinder 9 Blocking gt Move Vertex gt Set Location 4x12 Move Vertices Move Vertices PHAN Z I O N Method Set Position ha Reference From Vertex C Screen Ref Vertex K 105 R API Set Coordinate system Cartesian gt I Modyx x Eem M Mody Y tempy l Modwz Z fteme I ModifyNomal Mors f T Vertices to Set K 115 114 10 AN aoe apply OK _ Dismiss ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 153 Hexa Mesh Generation for an Elbow Part Ensure that Set Position is selected in the Method drop down list Ensure that Vertex is selected in the Reference From group box Click 3 Select vert s next to Ref Vertex and select one of the higher vertices as shown in Fig ure 120 Moving the Vertices on the Cylinder p 155 as a reference to which the other vertices will be moved Ensure that the Coordinate system is set to Cartesian Enable Modify Y Selecting Modify Y will allow you to move the vertices in the Y direction Click s Select vert s ne
33. DEZ b In the Display tree enable Edges and Vertices then right click Vertices and choose Numbers c Zoom in to one of the triangular transition regions in the center of the duct ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 315 Multizone Mesh in HVAC Square to circle Transistion Duct Figure 237 Transition Region Blocking 3 Check Mesh Quality and find lowest quality blocks Blocking gt Pre Mesh Quality Histograms Q a Accept all defaults and click Apply Notice the quality is all above 0 4 The model would be acceptable as it is but you will improve it further with interactive adjustments to the blocking This flexibility is one of the advantages of the Multizone method b On the Quality histogram click to select the three lowest bars below 0 6 The bars change color and the corresponding elements are highlighted ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 316 formation of ANSYS Inc and its subsidiaries and affiliates Checking the Mesh Saving and Exiting Figure 238 Location of Lower Q elements The inner edges blue will be adjusted to improve the quality 44 Blocking gt Move Vertex gt Align Vertices in line a For Reference Direction click s Select vert s b Select the two vertices as shown in F
34. DEZ d Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 239 Tetra Mesh in a Piston Valve Assembly Figure 186 Region between PORT and STEM for Thin cut Figure 186 Region between PORT and STEM for Thin cut p 240 shows a close up view of the region between the PORT and STEM parts where the Thin cut will be applied respecting the two surfaces 3 Specify Surface Mesh parameters Mesh gt Surface Mesh Setup a Click a Select surface s b With the mouse in the display area press a to select all surfaces c For Maximum Size enter a value of 16 Note Setting the maximum size on the surfaces will not affect Curvature Proximity Based Refinement set in an earlier step d Click Apply 4 Save the project File gt Save Project Mesh parameters will be saved along with the geometry in the tetin file ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 240 formation of ANSYS Inc and its subsidiaries and affiliates Generating the Mesh Generating the Mesh 1 Create the Tetrahedral Mesh Mesh gt Compute Mesh a Ensure Mesh Type is Tetra Mixed and Mesh Method is Robust Octree b Click Compute Allow the mesh generation process to complete Look for Finished Compute Mesh in the Message Window 2 In the
35. Figure 205 Aorta Parts p 268 Click the middle mouse button to accept the selection Tip Use the Toggle dynamics hotkey F9 option to toggle between selection mode and dynamic mode to better orient the geometry for easier selection of entities You can also hold down the CTRL key to toggle between selection mode and dy namic mode c Click Apply Note You could also create a unique part for each output surface for easier display selec tion in the solver Figure 205 Aorta Parts OUTLETS 4 Rename the part comprising the arterial wall to AORTA_WALL Rue gt jAORTA MESH PART 1 me Rename Enter AORTA_WALL in the New name dialog and click Done ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 268 formation of ANSYS Inc and its subsidiaries and affiliates Step 1 Creating Parts Extract the feature curve from the inlet and outlet surfaces Geometry gt Create Modify Curve X gt Extract Curves from Surfaces a Create Modify Curve ea set GEOM O S06 ys GL b7 Surfaces AORTA MESH PART 1 0 1 B sees Surface Type BSpline Faceted Extract Edges Check Topology Create New z Apply Dismiss a Expand the Parts section of the tree and deselect AORTA_WALL Parts AORTA_WALL The graphics display shows only the inlet and outlet surfaces b Click 8 Select surface s and then Sele
36. ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 210 formation of ANSYS Inc and its subsidiaries and affiliates Check the Mesh Quality The Complete Initial Mesh Figure 166 ty Check the Mesh Qual Check the mesh quality 1 istograms ty H Blocking gt Pre Mesh Qual t 3x3x3 inan select Determ down list drop Criterion In the a tons istogram Opt Retain the default settings for H b Click Apply C There may be negative determinants as a result of the order of vertex selection when creating blocks to finish the 2D grid Change the direction of inverted blocks 2 Blocking gt Block Checks 2 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 211 formation of ANSYS Inc and its subsidiaries and affiliates Bottom Up Hexa Mesh Strategy for a Grid Fin a From the Method drop down list select Fix Inverted Blocks b Click Apply Allow re compute when prompted Figure 167 Determinant Histogram after Fix Inverted Blocks Determinant 3x3x3 Max 0 999 Reduce the Blocks in a Multiblock Mesh Typically many splits are required to block a complicated geometry thereby producing many unnecessary blocks A large number of blocks increases the analysis computation time for multiblock solvers When writing a multiblock mesh output for some solvers it is be
37. Mesh dialog to compute the initial mesh 6 Disable Vertices and Edges Blocking De vertices ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 19 Hexa Mesh Generation for a 2D Pipe Junction Blocking De Edges The initial mesh is shown in Figure 13 Initial Mesh p 20 Figure 13 Initial Mesh SIRPETTESETORT ELT ESE 5 IFEF Le SEPTELISOLESEL IES SR ECPSTET SETS E Lif LORE it PAAIE LUI Z272 Le cnet SL ESEI rT es Sees gt ne 5 ee ees I ee Cates a KA oN WKS ee Ren oe 4 28o tas Ses oe a s eer os BK aA SRR MULUCUUERETESESSONG Se AREERLURRDRRCERS CS ENEAS MUSUERERRERERESE Note The number of elements in the initial mesh is sensitive to exact vertex placement longest edge length in an index divided by the maximum size found along that index Hence your mesh may differ slightly from the mesh shown in Figure 13 Initial Mesh p 20 Step 6 Adjust the Edge Distribution and Refine the Mesh In this step you will employ advanced edge meshing features to redistribute grid points to resolve the salient features of the flow 1 Disable Pre Mesh Blocking LB gt pre Mesh 2 Redisplay Curves and Edges 3 See the distribution of
38. Octree mesh with the Delaunay mesh because it has a smoother volume transition 1 Set the volume mesh parameters Mesh gt Global Mesh Setup Kol gt Volume Meshing Parameters amp ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 279 Tetra Prism Mesh Generation for an Aorta Global Mesh Setup 2 Global Mesh Parameters a BOOMS Volume Meshing Parameters Mesh Type Tetra Mixed v Tetra Mixed Meshing Mesh Method lo uick Delaunay v Delaunay Scheme Select C Standard TGlib M Use AF Memory scaling factor ir CS Spacing Scaling Factor ir CSC t S F Fill holes in volume mesh F Mesh internal domains F Flood fill after completion I Verbose output a f EEE Dismiss a Select Quick Delaunay from the Mesh Method drop down list b Retain the other settings and click Apply 2 Compute the mesh Mesh gt Compute Mesh gt Volume Mesh M ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 280 formation of ANSYS Inc and its subsidiaries and affiliates Step 4 Generating the Delaunay Mesh Compute Mesh P Compute AZ Volume Mesh Mesh Type Tetra Mixed ist Tetra Mixed Mesh Mesh Method Quick Delaunay x F Create Prism Layers F Create Hexa Core Volume Part Name
39. Save the project using a new name for example Hexa_Fin This preserves the original tetra prism mesh in one project the hexa core mesh in another File gt Save Project As Repeat the Checking and Smoothing steps completed earlier Edit Mesh gt Check Mesh Edit Mesh gt Smooth Mesh Globally amp amp 230 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Save and Exit Figure 180 Quality histogram for Hexa Core mesh 0 0 1 0 2 0 3 0 4 0 5 0 6 07 0 8 0 9 1 4 Find data for mesh comparison Info gt Mesh Info Scroll through the message window to find the number of elements in the FLUID part this part now includes the hexa elements as well as tetra and prism This time you should see a number less than 200 000 Save and Exit 1 Save the mesh File gt Save Project 2 Close the project File gt Close Project 3 Exit the program File gt Exit ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 231 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 232 formation of ANSYS Inc and its subsidiaries and affiliates Tetra Mesh in a Piston Valve Assembly In this tutorial example you will generate and smooth a
40. Screen select is chosen from the Split Method drop down list c Create splits as shown in Figure 107 Split Block p 143 by selecting any edge in the Y or X direction through which you want to run the perpendicular split Select the edge and hold down the left mouse button while moving the mouse Adjust the position such that the split is near the extent of the circular curve of the geometry Click the middle mouse button to accept the split position Figure 107 Split Block locations X 3 Delete the corner block Blocking gt Delete Block Pad a Select the block highlighted in Figure 108 Deleting the Block p 144 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 143 Hexa Mesh Generation for an Elbow Part Figure 108 Deleting the Block block to be deleted b Ensure that Delete permanently is disabled and click Apply Note Deleting a block without Delete permanently enabled will just change the mater ial to VORFN which is sufficient in most cases Use Delete permanently only in rare situations where you specifically want to break up blocking topology Step 3 Fitting the Blocking to the Geometry In this step you will associate the blocking edges to geometry curves and move vertices onto the geometry 1 Disable Surfaces so that the rest of the entities are clearly v
41. Select entities c Enable Toggle selection of curves 8 in the Select geometry toolbar d Disable Toggle selection of surfaces 8 in the Select geometry toolbar e Click select all appropriate objects or type a to select all the curves You need not click the middle mouse button when using the Select all appropriate objects or the Select all appropriate visible objects option ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 66 formation of ANSYS Inc and its subsidiaries and affiliates Step 2 Creating a Material Point f Click Apply in the Create Part DEZ 5 Create a new part comprising all the points in the geometry a Enter POINTS for Part in the Create Part DEZ b Retain the selection of Nx Create Part by Selection and click S Select entities c Enable Toggle selection of points 8 in the Select geometry toolbar x d Disable Toggle selection of curves in the Select geometry toolbar e Click x Select all appropriate objects or type a to select all the points f Click Apply in the Create Part DEZ Note The selection logic is flexible and there are many ways to select entities This step illus trated an example of selection logic Step 2 Creating a Material Point yai Geometry gt Create Body g gt Material Point Create Body P Part FLUID x ee ae latPi i Material Point Location Cen
42. Step 1 Block the Geometry Figure 7 Blocks to be Deleted 13 Click the middle mouse button or Apply to accept See Figure 8 Blocking Topology After Deleting Blocks p 10 Click Apply to remove the selected blocks Note With Delete Permanent disabled default the deleted blocks are actually put into the VORFN part a default dead zone that is usually deactivated The geometry and blocking of the model now resembles Figure 8 Blocking Topology After Deleting Blocks p 10 You may need to enable Blocks under Blocking in the Model Tree ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 9 Hexa Mesh Generation for a 2D Pipe Junction Figure 8 Blocking Topology After Deleting Blocks Step 2 Associate Entities to the Geometry You will associate the edges of the blocking to the curves of the CAD geometry in this step First select the edges and then the curves to which you want to associate them Note If two or more curves are selected per operation those curves will automatically be grouped concatenated For reference enable Show Curve Names see Figure 9 Display Showing Vertex Numbers and Curve Names p 11 Geometry Rue gt curves me show Curve Names This is not required for edge to curve association but helps to illustrate the fact th
43. T 177 Initiate 2D BlOCKING ii aeeiio ron Wawa Soncieediendaadey EEEE EO a E 177 Associate Initial Blocking to a Minor Geometry sssesssssessssssesssssressssressserersssreessssreessstessseressssrressssree 179 Create an O grid and Place Vertices eesssssesssesessssseessssressssseessseresssereesssreessssreesssetesssereessereessssreessee 184 Rotate and Copy to Resolve Other Geometries csssesceseesenceesesseeeescesseceeseeseneessesseeeeesesseseeseesenees 187 Complete the 2D Grid by Vertex Placement cssescccsesseccessesseseesesseneeeeessescescesseneeseesenseeserseaeesoesgs 189 Extrude a 2D Planar Grid to Create 3D Blocking ssssessssssssssssrssssseesssseessssressssreessseressssreesssreesssseeessseres 193 Refine the Blocking with Further Splits and Associations sssessessessessessssssessssseesssrressssressssresssssresssee 195 Resolve Zero Thickness Walls ss ic sssecavaaaiunps tevesanhovhad pravdbieadivs ius kages sewusdssounnaysapesaadysous bases abuse sansnrbaaponnteaetboans 203 Define Periodicity Faye tenens vennnteavuctirg olevsultoaiytasuncnsedeiya spine paderaulion i AEE A E NE AE E Eaa 207 G erate th M Shirsineri eneore a a A E un aa TE N E E acta anunacro E E RERE 209 Check the Mesh Qual e aeaa dahon aa a A AOT a EE r e EE Dae E AE EA ESE eA Oaia 211 Reduce the Blocks in a Multiblock Mesh essssscccessescesesseeceesesseneescesseseeseesenseesenseseeesesseseeseesenees 212 Save the Mesh radien
44. and solve for transient laminar flow Further Setup You can solve this example for transient laminar flow using ANSYS FLUENT A basic setup could include the following e Material properties Density 1060 kg m Viscosity 0 0035 kg m s e Solver setup transient laminar flow Boundary conditions ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 286 formation of ANSYS Inc and its subsidiaries and affiliates Further Setup The transient velocity profile one cycle is available with the tutorial example file AorticIn flowWave form prof The profile assumes a cardiac output of 6 8 I min and 75 beats per minute Note Run at least 1 5 cycles to remove the effects of the initial condition Assume zero pressure at the outlets e Post processing The periodic solution can be visualized by plotting the inlet pressure for 3 cycles Other results of interest include wall shear static pressure on the wall and velocities along the length A more advanced setup could include two way FSI which can be done using ANSYS ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 287 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 288 formation of ANSYS Inc and its subsidiaries and af
45. and then Dismiss Create Automatic Surface Blocking A 2D Surface Blocking will be created The Blocking will be forced to respect the curves identified in the Build Diagnostic Topology step 1 Initiate the 2D blocking Hees Blocking gt Create Block Z gt Initialize Blocks g 2 In the Type drop down list select 2D Surface Blocking 3 Under Surface Blocking in the Method drop down list select Mostly mapped 4 In the Free Face Mesh Type drop down list select Quad Dominant 5 Under Merge blocks across curves in the Method drop down list select None 6 Leave all other default settings Note By not selecting any surfaces explicitly all surfaces will be meshed ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 308 formation of ANSYS Inc and its subsidiaries and affiliates Create Automatic Surface Blocking Create Block Part V Inherit Part Name Create Block w m Initialize Blocks Type 20 Surface Blocking Surfaces X ee Surface Blocking Method Mostly mapped z Free Face Mesh Type Quad Dominant Ms Free Face Mesh Method ICEM CFD Quad vi Merge blocks across curves Method None b Ignore size foo IV Initialize with settings 7 Click Apply The curves turn multicolored because this is more useful in the blocking phase of meshing In the Display tree Curve display settings switch from Color by Count
46. curves to which they are associated If you skip performing the curve associations the boundary line elements will not be created This will make it im possible to apply boundary conditions to that edge such as inlet or wall Hence most CFD solvers give errors if any of the perimeter edges are not associated with perimeter curves ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 15 Hexa Mesh Generation for a 2D Pipe Junction 2 3 Move the remaining vertices to their appropriate positions on the geometry Try to make the blocks as orthogonal good internal angles as possible Figure 12 Vertices Moved to Positions Associate the vertices to the points This is an optional step a Select Show Point Names Geometry e points Show Point Names Make sure Point is selected for Entity in the Associate Vertex DEZ Blocking gt Associate amp gt Associate Vertex eo Associate the following vertices and points Ver Point 13 POINTS 2 21 POINTS 5 41 POINTS 1 42 POINTS 10 33 POINTS 9 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 4 Apply Mesh Parameters 37 POINTS 8 43 POINTS 11 Click the middle mouse button to c
47. direction See Figure 32 Edge and Vertex Selection p 46 The program assumes the alignment to be in the Y direction vertical of the active coordinate system so only the X and Z in this case Z is undefined coordinates will be adjusted b Click Select vert s and then select any of the top four vertices for example 5 2 1 as shown All vertices with J 2 will be fixed and all other visible vertices will be moved into alignment Observe that XZ under Move in plane is automatically toggled on Figure 32 Edge and Vertex Selection p21 21 21 11 11 S814 11 Select Vertex Select Edge c Click Apply The bottom vertices are adjusted to line up with those at the top See Figure 33 Aligned Bottom Ver tices p 47 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 46 formation of ANSYS Inc and its subsidiaries and affiliates Align the Vertices Figure 33 Aligned Bottom Vertices Click Reset in the Index control panel to display all blocks In the Display Tree enable the display of Numbers for the Vertices Blocking Vertices Numbers Set the location for a moved vertex Blocking gt Move Vertex gt Set Location 4x12 Vertex positions can also be adjusted by setting coordinates In this case the new coordinates will be extracted from a reference vertex a For Ref Vertex click Select vert s and then select Vertex 92 near
48. edges MV Uncovered faces IV Triangle boxes vi iaie internal I 2 single edges aces ae ee Single roultiple Periodic problems R ie z Stand alone Volume orientations T eames V Surface orientations V Single edges Hanging elements l Delaunay violation Penetrating r Overlapping elements elements Disconnected bar Non manifold x elements Vv vertices Unconnected M vertices Set defauts 2 Apply ox Dismiss a Retain the default set of checks b Click Apply to check for errors and possible problems in the mesh Make sure no errors problems are reported during the check Step 4 Generating the Delaunay Mesh In this step you will replace the Octree mesh with the Delaunay mesh because it fills the volume more effi ciently and has smoother volume transition 1 Set the volume mesh parameters Mesh gt Global Mesh Setup Kol gt Volume Meshing Parameters amp ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 259 Tetra Prism Mesh Generation for a Helicopter Global Mesh Setup Q Global Mesh Parameters a BO Ow Volume Meshing Parameters Mesh Type Tetra Mixed h Tetra Mixed Meshing Mesh Method Quick Delaunay yi Delaunay Scheme Select C Standard TGlib M Use AF Memory scaling factor fi Spacing Scaling Factor fi2 xl Apply Eoi Dismiss a Select Quick
49. elements are five sided elements with six nodes such as prism ele ments These elements are usually ideal but may be damaged by the smoother as it adjusts to optimize the adjacent tetra nodes Freezing these prism elements PENTA_6 protects them If you smooth some prism elements use a subset or re duce the number of smoothing iterations and the Up to value down to 0 01 so that only the worst elements are adjusted e Click Apply The quality histogram will be updated as shown in Figure 202 Updated Quality Histo gram p 263 Figure 202 Updated Quality Histogram 24 2 Smooth the interior elements including the prisms a Enter 2 for Smoothing iterations b Enter 0 01 for Up to value c Select Smooth for PENTA_6 d Click Apply Step 6 Saving the Project 1 Save the project file helicopter final prj File gt Save Project As 2 Save the output file for ANSYS FLUENT ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 263 Tetra Prism Mesh Generation for a Helicopter Output gt Select solver gt a Select ANSYS Fluent from the Output Solver drop down list b Click Apply 3 Set the appropriate boundary conditions Output gt Boundary conditions ae e Click Accept to set the boundary conditions 4 Write the input file for ANSYS FLUENT Output
50. enable Point Click Select vert s and then select vertex 33 Click Select point s and then select the point POINTS 18 Click Apply to complete the association The vertex moves immediately to the associated point Similarly associate vertex 35 to point POINTS 14 Move middle O grid vertex a Display the front view View gt Front Fix the direction of the vertex Blocking gt Move Vertex gt Move Vertex P i Under Movement Constraints enable Fix direction ii For Vector click Select edge s and then select edge 13 34 vertical edge Move the middle vertex i In the Move Vertex DEZ click Select vert s ii Click and drag vertex 34 towards vertex 13 iii Click the middle mouse button to accept The blocking after vertex placement is shown in Figure 145 Blocking after Vertices are Moved p 187 186 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Rotate and Copy to Resolve Other Geometries Figure 145 Blocking after Vertices are Moved POINTS 26 BBINTS 14 POINTS 2 OINTS 25 Rotate and Copy to Resolve Other Geometries Copy Rotate will be used to resolve other triangular portions of the blocking grid However since it also copies existing associations all blocking must first be disassociated from the geometry In effect associations were
51. fin o atPi z Geometry gt Create Body G gt Material Point a For the Part name enter FLUID b Click on amp Select location s c Select two locations such that their midpoint is within the region inside the box For example choose one on the fin tip and one at a box corner d Click the middle mouse button to accept e Click Apply Setup Mesh Parameters Maximum mesh sizes on various surfaces and volumes are defined First the Global Mesh parameters are defined then further refinement is applied individually to surfaces and a Density region 1 Set Global Mesh Size Mesh gt Global Mesh Setup Kol gt Global Mesh Size B a For Max element enter a value of 32 b For Scale factor enter a value of 1 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 221 Tetra Prism Mesh in a Fin Configuration This parameter is referred to by other mesh parameters The Scale factor allows you to globally control the mesh size instead of changing the mesh size on each and every entity For more inform ation refer to Global Mesh Size in the Help document Click Apply Set Surface Mesh parameters on the external surfaces Mesh gt Surface Mesh Setup 6 Click B Select surface s and then click the six surfaces that form the external box structure Click the middle mouse button to accept
52. grid points along the edges Figure 14 Initial Bunching p 21 Blocking Rue Edges e bunching ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 20 formation of ANSYS Inc and its subsidiaries and affiliates Step 6 Adjust the Edge Distribution and Refine the Mesh Figure 14 Initial Bunching Display the vertex numbers Blocking PE Vertices 2 Numbers Reduce the number of nodes along the length of the large pipe Blocking gt Pre Mesh Params 9 gt Edge Params I ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 21 Hexa Mesh Generation for a 2D Pipe Junction Pre Mesh Params E Meshing Parameters a T o3 ER A I I I Edge EEEN EN atte Length 38 2322 Nodes zo g Mesh law BiGeometric v Spacing 1 booo 1 47047 I Spt Linked lt Reverse Roi f Spacing 2 booo 1 47047 7 Sp2Linked Seic Beverse Raio2 2 OS Max Space ae 1 47047 l Spacing Relative P Nodes Locked Parameters Locked Copy Parameters r Co Linked bunching x Apply ERA Dismiss a Select edge 13 34 b Enter 27 for Nodes and click Apply c Similarly click a Select edge s select edge 21 38 enter 27 for Nodes and click Apply Note This is a structured grid When the number of nodes is changed on one edge all paralle
53. gt Write input my a Select the appropriate uns file The ANSYS Fluent dialog will appear ANSYS Fluent Please edit the following ANSYS Fluent options Grid dimension 3D C 2D Scaling Yes No Write binary file C Yes No Ignore couplings Yes No Boco file helicopter final be Output file p S users Project fluent Done Cancel b Enter fluent for Output file c Click Done 5 Exit the current session File gt Exit ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 264 formation of ANSYS Inc and its subsidiaries and affiliates Tetra Prism Mesh Generation for an Aorta This tutorial demonstrates the generation of a tetra prism mesh for an aorta starting from STL data The aorta geometry used in this tutorial is courtesy of Marc Horner an ANSYS Inc engineer and Mater ialise Inc who extracted the geometry from the MRI scan images Figure 203 Aorta Geometry This tutorial demonstrates how to do the following Import STL data into ANSYS ICEM CFD Set up global and part parameters for meshing Generate the mesh using the Octree approach Generate the mesh using the Delaunay approach Examine the mesh using cut planes Smooth the mesh to improve the mesh quality Preparation Step 1 Creating Parts Step 2 Creating the Material Point Step 3 Generating the Octree Mesh Step 4 Generating th
54. iai anri AE E E E E LEA E a aa a a a 215 Tetra Prism Mesh in a Fin Configuration eee ee eseecccesssnceceessceeeeesnaceecesssaeeceessaeeeeesssaeeeeestneeees 217 Prepare the GEOMethy ryn arra a E EEEE EAE EEEE EEEE AE REEE AE 217 Create Surface and Material Parts sisccsusresaarsesnddchesosasedvnavinvssaesenuitessduanansaueananrcenandaasdnnenadbepiadsadeiuens 219 Setup Mesh Parameters anrora at ye R in a A E EEI AA E aE E EAEE AEA RR 221 Generate the Tetra Prism Mesh ssssssssssessssssesssssessseseessssressssseessseteessereesssseesssereesssetesssereesseeessssressseeees 225 Check and Smooth the Tetra Prism Mesh s sssssessessessssssessssseessssressssressssttessssreessstresssereesssreessssresssseeesse 227 Build the Hexa Core meshsssiiessiiiiioeesni iieii aK EE E E EEE AKEE EE a i aioe 229 Save aNd EKE sasha e eara N EEEE Eaa E AERA ae E EE E Eaa 231 Tetra Mesh in a Piston Valve Assembly 0000 eeeesccceesssneeceessneeeceessaceccessaeeecessnaeeecessaaeeeeessaeeesesenaeeeees 233 Starting the PiOjSel Aicpevaniscacedeaa sens eysetnereacnwedony el iedets HG ennai Meunayot dear Olena ageara E aE 234 Defining the PANES sti ises capes sevens uchussosaisauys tous depen naveeanaatiunpesgintsdvune Capes mvesnesnas ua pa ey away oawedasnRoRanaS 235 Setting Mesit PabaIinete rs v ssivnestansveysayonleinvuingutesaiamearnusanesasanynuet aa aa A a a Ea a a rie 238 SHSM SEIN th Meshsi ssdri riges ieioea eae vacancies ata cma send ah nod hedhtnet
55. laws warranties disclaimers limitations of liability and remedies and other provisions The software products and documentation may be used disclosed transferred or copied only in accordance with the terms and conditions of that software license agreement ANSYS Inc is certified to ISO 9001 2008 U S Government Rights For U S Government users except as specifically granted by the ANSYS Inc software license agreement the use duplication or disclosure by the United States Government is subject to restrictions stated in the ANSYS Inc software license agreement and FAR 12 212 for non DOD licenses Third Party Software See the legal information in the product help files for the complete Legal Notice for ANSYS proprietary software and third party software If you are unable to access the Legal Notice please contact ANSYS Inc Published in the U S A Table of Contents Hexa Mesh Generation for a 2D Pipe Junction ec ccceesseecceceeceesessneeeeeeceesseesnaaeeceeeeeeseeesnaeeeeeeeeens 1 Preparations Seanoinn eee cis wuea sa Deas cid cava cove seddec gs uv Sunvoudetee dunes vevsccce dou suyesevscedes sedans cov E E AESA 2 Blocking Strategy roino EEE E EEA E E EEE E E vente E EEE E a E 2 Step 1 Block the GEometry nrcisvicnsancssssvassvnnsrtadivansidivoesnduiessaveulvnnadeussnerauurinens Ears E a E iik 3 Step 2 Associate Entities to the Geometry ssssessssssesssssesssssessssreesssstessseteessseessssrees
56. of surfaces curves and points then the mesh will contain a mixture of element types and the part will be located in the Mixed unknown branch of the tree If you apply wall properties these are applied to the shells in that part only 5 Write the input file for ANSYS FLUENT Output gt Write input my a Select the appropriate uns file ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 172 formation of ANSYS Inc and its subsidiaries and affiliates Step 9 Saving the Project The ANSYS Fluent dialog will appear ANSYS Fluent Please edit the following ANSYS Fluent options Grid dimension 3D C 2D Scaling Yes No Write binary file C Yes No Ignore couplings Yes No Boco file project fbe Output file elbow Done Cancel b Enter elbow for Output file c Click Done You can read this mesh file and proceed to setup and solve in ANSYS FLUENT ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 173 174 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Bottom Up Hexa Mesh Strategy for a Grid Fin In this tutorial you will generate a hexa mesh for a Grid Fin This could be done with top d
57. plane for Refer ence vertex see Figure 121 Aligning Vertices p 156 c Ensure that XZ is selected in the Move in plane group box d Click Apply Figure 121 Aligning Vertices Pd Se es Pal we a p Fa f x Pa 2 j Hp Sa r fa LA f Fil d p es Pa f f Fi f P Fd f ra iil FLUIY D i E reference i edge pe A me Z S N Ra N X pi x lt reference S Y gt S N KR vertex x a 7 Before Aligning Vertices After Aligning Vertices ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 156 formation of ANSYS Inc and its subsidiaries and affiliates Step 5 Adjust the O Grid Edge Length to Improve Quality 5 Realign the vertices on the geometry After aligning the edges you may notice that some vertices have moved off the geometry a little bit Figure 122 Vertices Moved Off the Geometry p 157 You will now use Snap Project Vertices to realign them Figure 122 Vertices Moved Off the Geometry vertices moved off the geometry 4 FLUID OLID wor Blocking gt Associate gt Snap Project Vertices ae Repeat the steps for aligning to the base plane and snap vertices until you get the geometry right Figure 123 Vertex Positions After the Final Alignment p 157 Figure 123 Vertex Positions After the Final Alignment vertices moved Before Using Snap After Using Snap Project Vertices Project Vertices 6
58. selecting curves for parts could become tedious ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 93 Hexa Mesh Generation for a Sohere Cube Geometry Step 2 Creating a Material Point yeli Geometry gt Create Body g gt Material Point 1 Enter FLUID for Part 2 Ensure that Points is enabled in the display control tree 3 Click amp Select location s and select two locations such that the midpoint lies within the volume Figure 67 Selection of Locations for Creating Material Point p 94 Click the middle mouse button to accept the selection of the locations Figure 67 Selection of Locations for Creating Material Point 4 Click Apply so that FLUID appears under Parts in the display control tree Rotate the model to confirm that the new material point is within the volume and does not just appear so from one perspective Note The use of a material point is not actually required However creating one will fix the volume part name within the tetin file This will avoid any problems caused by the volume name in the block file not being recognized by the tetin geometry file in future sessions 5 Save the geometry file sphere cube new tin File gt Geometry gt Save Geometry As ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and conf
59. tetrahedral mesh for a piston valve configuration The complete geometry is shown in Figure 181 Piston Valve Geometry p 233 In the process you will use features of ANSYS ICEM CFD designed to improve your efficacy when working with certain types of geometries The first tool is Build Diagnostic Topology This tool creates curves and points from surface edges and corners depending on their proximity It will also remove curves or points when surfaces or curves meet below a specified shallow angle See the Help Document for more detail on Build Topology Also you will be required to define a thin cut in the Geometry to mark a region where ANSYS ICEM CFD Tetra will respect two surfaces that meet at a shallow angle See Meshing Inside Small Angles in the User Manual for more information Similarly Curvature Proximity Based Refinement is used to resolve geometries with small radius of curvature or in close proximity to one another See the Help menu Global Mesh Size for more information on Curvature Proximity Based Refinement Figure 181 Piston Valve Geometry This tutorial demonstrates how to do the following ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 233 Tetra Mesh in a Piston Valve Assembly Starting the Project Defining the Parts Setting Mesh Parameters Generating the Mesh Checking the mesh and Clean
60. will be used to provide a more uniformly spaced mesh Finally the Hexa Core utility will be used to reduce the element count in the main volume This tutorial demonstrates how to do the following Prepare the Geometry Create Surface and Material Parts Setup Mesh Parameters Generate the Tetra Prism Mesh Check and Smooth the Tetra Prism Mesh Build the Hexa Core mesh Save and Exit Prepare the Geometry 1 Copy the input geometry file geomet ry tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files FinConfig to the working directory 2 Start ANSYS ICEM CFD and create a new project in your working directory Use an appropriate name for example Tetra_Fin File gt New Project 3 Open the geometry file geomet ry tin File gt Geometry gt Open Geometry 4 Repair the geometry Geometry gt Repair Geometry Ss gt Build Diagnostic Topology A a Accept all default parameters b Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 217 Tetra Prism Mesh in a Fin Configuration Figure 170 Fin Configuration Geometry with Build Topology zZ Note Display of Surfaces has been enabled in the Display tree Curve colors Red indicates a curve at the intersection of two surfaces Blue indicates a curve at the intersection of more than two surfaces Not
61. 0 Cut Plane in X Direction for the Octree Mesh p 277 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 276 formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Generating the Octree Mesh Figure 210 Cut Plane in X Direction for the Octree Mesh g Disable Show Cut Plane in the Manage Cut Plane DEZ Smooth the mesh The smoothing approach involves initial smoothing of the interior elements without adjusting the prisms After initial smoothing you will smooth the prisms as well Edit Mesh gt Smooth Mesh Globally The quality histogram appears in the right hand corner ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 277 Tetra Prism Mesh Generation for an Aorta Smooth Elements Globally Quality a Smoothing iterations 20 a Up to value 0 20 Criterion Quality x Smooth Mesh Type Smooth Freeze Float Smooth Parts Subsets Method AII parts Refresh Histogram Apply Dismiss a Enter 20 for Smoothing iterations and 0 2 for Up to value b Retain the selection of Quality in the Criterion drop down list c Select Freeze for PENTA_6 d Retain the other settings and click Apply The quality histogram will be updated e Enter 5 for Smoothing iterations and 0 01 for Up to value f Select Smooth for PEN
62. 1 f Similarly create a horizontal split through PNTS 4 g Change the Index range to I 2 5 and J 3 4 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 39 Hexa Mesh Generation for a 2D Car Figure 25 Additional Vertical and Horizonal Splits SPNTS h Create two more vertical splits through points PNTS 8 and PNTS 2 i Click Reset in the Index Control panel j Disable the display of Points See Figure 26 Fully Split p 40 Figure 26 Fully Split Delete unnecessary blocks Blocking gt Delete Block Pad Currently all of the blocks are in the FLUID volume part For flow analysis only the blocks outside of the car should be retained Therefore blocks representing the interior of the car are reassigned to a different volume part a Enable the display of Blocks Blocking Blocks This will show the blocks by their numbers b Click Select block s and then select the block to be deleted as shown in Figure 27 Blocks to Delete p 41 The blocks selected for deletion are 17 28 26 36 30 31 and 33 Your block numbers may differ 40 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Create and Split the Blocking to Resemble the Geometry Figure 27 Bl
63. 3 Enter 1 for Maximum size Note Maximum size determines the length of the edge segments on the curve or surface for 3D Height determines the length of the edge of the first layer normal to the curve Height ratio determines the normal heights of the subsequent layers ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 18 formation of ANSYS Inc and its subsidiaries and affiliates Step 5 Generate the Initial Mesh In this case height and ratio are determined by the perpendicular curves whose maximum size will override any height or ratio settings 4 Retain the default settings for all other parameters and click Apply Step 5 Generate the Initial Mesh Blocking gt Pre Mesh Params Update Sizes y Pre Mesh Params D Meshing Parameters a CA Ne Recalculate Sizes Method Update All Keep Distributions Keep Counts Curve gt Edge bunching MV Run Check Fix Blocks z Apply oe Dismiss 1 Retain the selection of Update All in the Method list Note This will automatically determine the number of nodes on the edges from the mesh sizes set on the curves 2 Select Run Check Fix Blocks to check for mesh problems automatically and repair them if possible 3 Click Apply 4 Enable Pre Mesh Blocking De pre mesh The Mesh dialog will appear asking if you want to recompute the mesh 5 Click Yes in the
64. 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 38 formation of ANSYS Inc and its subsidiaries and affiliates Create and Split the Blocking to Resemble the Geometry Asta hid ki 4 Select comers fo 4 l 5 4 Reset J fo telf t l K jo 4l fi 4 l Query Edge Index Sets Done xi Note This Index Control panel has two columns Min and Max All block edges and vertices are assigned index values J and K For example the first edge perpendicular to the x axis of the global coordinate system has an index of 1 while the first edge per pendicular to the y axis has an index of J 1 For 2D cases such as this the K index is undefined To change the range toggle the arrows or enter an integer value in the appropriate field Only the blocks within this range are displayed e Click Reset to select all of the block indices b Change the Index range to l 2 3 and J 1 3 to display only the blocks containing the vehicle and those underneath the vehicle Note As stated this manages the visible propagation of splits Implied splits are still propagated behind the scenes in order to maintain structured block continuity You can expose these implied splits using Extend Splits c Select any horizontal edge and create a vertical split through PNTS 7 d Similarly create a vertical split through PNTS 4 e Select any vertical edge and create a horizontal split through PNTS
65. 59 Elements with Worst Quality p 80 Most of the bad elements with the worst angles are on the block corners This is due to the H grid nature of the mesh within a curved geometry ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Hexa Mesh Generation for a 3D Pipe Junction Figure 59 Elements with Worst Quality d i _ a 6 Right click in the histogram window and select Done Step 8 Creating an O Grid in the Blocking In this step you will create an internal O Grid to improve the angles in the block corners This is the best method for fixing bad angles in block corners within cylindrical geometry ANSYS ICEM CFD has a specific O Grid tool to make it easy to accomplish even on complicated geometry Before proceeding to this step make sure that your surface vertices are aligned as you want them and internal edges are straight The O Grid tool offsets the boundary faces orthogonally and you may end up with twice as many vertices It is convenient to adjust your surface blocking to ideal locations before O Grid than after 1 Enable Surfaces Geometry Surfaces 2 Create the O Grid Blocking gt Split Block gt gt Ogrid Block CA ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 80 formation of ANSYS Inc and its subsidiaries and affil
66. A y vay V VV P OX 1 A Vi y d yh j LA j Yy A j 4 j V j _ y WN LX Lg i INTERFACE1 INTERFACE2 The steps to complete this tutorial are listed Starting the Project Setting the Mesh Parameters Generating the Tetra Mesh in CYL1 Generating the Tetra Mesh in CYL2 Merging the Tetra Mesh between CYL1 and CYL2 Generating the Hexa Mesh in CYL3 Merging the Tetra Mesh with Hexa Mesh at Interface2 Cleaning up and Saving the Project ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 289 Merged Tetra Hexa Mesh in a Hybrid Tube Starting the Project 1 Copy the input geometry file geomet ry tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files HybridTube to the working directory Start ANSYS ICEM CFD and create a new project in your working directory Use an appropriate name for example HybridTube File gt New Project Open the geometry file geometry tin File gt Geometry gt Open Geometry Note If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Throughout this and other tuto
67. ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 70 formation of ANSYS Inc and its subsidiaries and affiliates Step 4 Projecting the Edges to the Curves Figure 52 Block to be Deleted block to be deleted Step 4 Projecting the Edges to the Curves Blocking gt Associate amp gt Associate Edge to Curve So Blocking Associations Edit Associations a DOTTO ADX Associate Edge gt Curve Edgels 25730 73 74011 AE Curve s GEOM 24 GEOM 28 GI R oo Project vertices 7 Project to surface intersection Project ends to curve intersection zi Apply OK Dismiss 1 Disable Surfaces ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 71 Hexa Mesh Generation for a 3D Pipe Junction Geometry Surfaces When associating edges to curves you need to display only curves and edges Hence you can disable unwanted entities to avoid confusion Associate the three edges at the top A with the three curves forming the small semicircle A See Figure 53 Edges Associated to Curves p 72 Figure 53 Edges Associated to Curves a Click a Select edge s and select the edges denoted by A Click the middle mouse button to accept the selection b Click amp Select compcurve s and select the curves deno
68. Display Tree under Mesh expand Shells and ensure Triangles is enabled Right click on Shells and then enable Solid amp Wire display for the surface mesh Zoom in on the region between PORT and STEM where the thin cut was defined the mesh should resemble Figure 187 Initial Mesh at PORT STEM Intersection p 241 The surfaces of the PORT and STEM are respected and the mesh elements are made smaller to resolve the short radius of curvature of the STEM Figure 187 Initial Mesh at PORT STEM Intersection 3 Display the tetrahedral volume mesh a In the Display tree enable Volumes and disable Shells b Right click on Volumes and then select Solid amp Wire c Right click on Mesh mouse over Cut Plane and then select Manage Cut Plane d In the Fraction Value box enter a value of 0 415 This will place the cut plane at approximately the middle of the valve stem ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 241 Tetra Mesh in a Piston Valve Assembly Figure 188 Tetra Volume Mesh around Valve 4 Create the Prism Mesh Prism layers on the surfaces allows for efficient capture of shear or boundary layer physics a Inthe Part Mesh Setup dialog box enable Prism for all surface parts except the SHROUD Mesh gt Part Mesh Setup a ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains
69. EOM 12 _BEOM 13 EOM 11 ea BEOM 14 _BEOM 15 we Enable the display of Surfaces zbe Surfaces Create surface part assignments RMB gt parts E Create Part Create Part Q Part PART Create Part HAS Create Part by Selection Entities M P Adjust Geometry Names z Apply ILo Dismiss a Follow this sequence to assign the region enclosed by GEOM 4 GEOM 7 to the part OUTLET i Type the name OUTLET in the Part field ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 111 Hexa Mesh Generation for a Pipe with Embedded Blade vi Ensure iis Create Part by Selection is selected Click x Select entities The Select Geometry toolbar appears Select geometry DAZK n x S EFA A amie D x Ensure Toggle selection of points is off Similarly toggle off x Toggle selection of curves and ba Toggle selection of bodies Leave only Toggle selection of curves 8 enabled Select the surface defined by the points GEOM 4 GEOM 7 Click the middle mouse button to accept Click Apply The surface geometry changes color and your new part name appears in the Display tree b Similarly reassign the region that is enclosed by points GEOM 0 GEOM 3 to the part INLET Also assign the surface defining the cylindrical pipe to a part named CYL Final
70. ET part ii Click the middle mouse button after selecting the faces c Click Apply to create the O Grid Figure 127 The Second O Grid p 161 Figure 127 The Second O Grid EZ A o Tir L T ir A X mT v x is j 3 Set the edge length to improve quality Blocking gt Move Vertex gt Set Edge Length e a Click Ss Select edge s and select one of the edges shown in Figure 128 Resizing Edges First Pair p 162 Click the middle mouse button You can see that the length is approximately 15 You will reduce this to improve the quality b Select the two edges shown in Figure 128 Resizing Edges First Pair p 162 c Enter 5 for Length and click Apply Figure 128 Resizing Edges First Pair p 162 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 161 Hexa Mesh Generation for an Elbow Part Figure 128 Resizing Edges First Pair edges to be resized d Similarly rescale the edges shown in Figure 129 Resizing Edges Second Pair p 162 to a value of 8 Figure 129 Resizing Edges Second Pair resized 4 Recompute the pre mesh a Disable SOLID E Parts LM SOLID b Enable Pre Mesh and click Yes to recompute Blocking Pre Mesh c Update the pre mesh parameters Since the edges were computed before they did
71. Ensure that Toggle between all and partial enclosure is selected as shown in Figure 159 Select Block face toolbar with Toggle All enabled p 204 c Click zal and then select the area as shown in Figure 160 Selection polygon for Association to PLATE1 p 205 204 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Resolve Zero Thickness Walls Figure 160 Selection polygon for Association to PLATE1 When using the polygon selection method draw the polygon by clicking corner points around the perimeter of the selection area Click the middle mouse button to finish the polygon d Click middle mouse button to accept the polygon selection e Click Select parts s The Select parts window opens f Select PLATE1 and click Accept g Click Apply 4 Similarly associate the face identified in Figure 161 Selection polygon for Association to PLATE2 p 205 with the part PLATE2 Figure 161 Selection polygon for Association to PLATE2 5 Similarly associate the four faces with the part SHELL ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 205 Bottom Up Hexa Mesh Strategy for a Grid Fin Ensure to select the regions one by one The Part must be SHELL for each of them Figure 162 Fou
72. M CFD provides a projection based mesh generation environment All block faces between different materials are projected to the closest CAD surfaces Block faces within the same material may also be associated to specific CAD surfaces to allow for the definition of internal walls In general there is no need to perform any individual face associations to underlying CAD geometry which reduces the time for mesh generation 1 Create an initial block Lp ana Blocking gt Create Block gZ gt Initialize Blocks g ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 68 formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Blocking the Geometry Create Block 9 Part FLUID pe J Inherit Part Name Create Block Initialize Blocks Type 3p Bounding Box v Entities aa Project vertices F Orient with geometry l 2D Blocking V Initialize with settings al Apply Dismiss a Ensure that Part is set to the correct material FLUID b Retain the selection of 3D Bounding Box in the Type drop down list You need not select entities when creating a bounding box around the entire geometry c Click Apply 2 Split the initial block into sub blocks Blocking gt Split Block B gt Split Block a Enable Curves and Surfaces Geometry Curves Geometry Surfaces b Display the left view for better visualization mi The L shaped topo
73. RATE KEE OT NEEE EERE 266 STEP 1 Creating Parts rasoio i ra aa dhde A E E dos a ends ia ES a A E A AR E A a a N 267 Step 2 Creating the Material Point eesssssssssssessssseessssresssssesssseressseressssttessssreessstresssereessereessssreessseresse 270 Step 3 Generating the Octree Mesh sesssessesssseessssressssseessseressssrresssstessssreessssresssereesssetesssetesessseesssene 271 Step 4 Generating the Delaunay Mesh ssssssssssssssssssesssssesssssressseressseteesssressssstesssetessseeesssressssreessee 279 Step 5 Saving the Projectes raii a a E a EE E E E N 283 F rther Set pasenes enairat EAEE EEA REA EEEE EE E ET AE OE EES 286 Merged Tetra Hexa Mesh in a Hybrid Tube 00 eee eee eeeeceesseeeeeessneeeceesnaeeecessaeeceessaceecessnaeeseesnaneeees 289 Starting the Pr jetts isserrat 290 Setting th Mesh Par amelel sic ca adadessnsadecinedasliarsaiss asada ei een EEE E E dnyswsasacvupindicpratesuvudadeens 290 Generating the Tetra Mesh in CYL1 essssessssssesssssessseseessssressssseessseresssereesssseessseseesssetessseteesssseessssreessee 291 Generating the Tetra Mesh in CYL2 e ssssessssssesssesessseseessssressssstesssetesssereesssstessssseesssetesssereesssreessssreessee 293 Merging the Tetra Mesh between CYL1 and CYL2 essssssesssssesssssessssseessssressssreessseressssreesssreessssreessseres 295 Generating the Hexa Mesh in CYL3 essssessssssessseseesssseessssressssreessseresssereessssressssseesssetessseeessss
74. SYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 9 Viewing the Scan Planes Figure 77 Initial Mesh Step 9 Viewing the Scan Planes Viewing the volume mesh can provide another good visual diagnostic Within blocking this is done by means of a scan plane where an I J K or radial O Grid index plane is scrolled through the volume 1 Display the Edges and Curves Blocking Edges Geometry Curves 2 Disable Pre Mesh Blocking Pre Mesh 3 Select Scan Planes Blocking Pre Mesh Scan planes The scan plane control window appears in the lower right hand corner of the screen The scan plane is not planar For instance enabling 0 displays all the nodes of constant index not constant X coordin ates You need to click the up down arrows for either Block Index or Grid Index to move the scan plane Block Index increments one block at a time whereas Grid Index increments one node at a time ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 105 Hexa Mesh Generation for a Sohere Cube Geometry On Block Index Grid Index Color wef 41 sip t Select main Abl 4 Solid ra2fo Asl tll Dore rap AA NA a Enable On for the index plane 0 0 1 2 represent J K respectively
75. SYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 299 Merged Tetra Hexa Mesh in a Hybrid Tube Figure 223 Set Parameters for Longitudinal Edge c Leave all other values unchanged and click Apply 8 Display the Hexa mesh a In the Display tree under Blocking enable Pre Mesh b When prompted click Yes to recompute the mesh Figure 224 Hexa Mesh in CYL3 region LIVE Y Z ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 300 formation of ANSYS Inc and its subsidiaries and affiliates Merging the Tetra Mesh with Hexa Mesh at Interface2 In the Display tree Edges Vertices Curves and Surfaces are disabled Pre Mesh is displayed as Solid amp Wire Save the blocking information file File gt Save Blocking As 10 In the Display tree disable Blocking and enable Mesh Surfaces and Curves Merging the Tetra Mesh with Hexa Mesh at Interface2 The hexa mesh will now be merged with the existing tetra mesh at INTERFACE2 The two meshes are made conformal by the addition of a pyramid layer at the surface 1 Open the hexa mesh File gt Mesh gt Load from Blocking The Mesh Exists dialog box opens Choose Merge In the Display tree turn OFF all parts except INTERFACE2 and then reorient the model for an end view Make the two meshes confor
76. SYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 61 62 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Hexa Mesh Generation for a 3D Pipe Junction In this tutorial you will generate a mesh for a three dimensional pipe junction After checking the quality of the initial mesh you will create an O Grid in the blocking to improve mesh quality Figure 48 3D Pipe Geometry This tutorial demonstrates how to do the following Create parts for the geometry Create the material point e Block the geometry Project edges to the curves e Move the vertices Generate the initial mesh Check the mesh quality Create an O Grid in the blocking e Verify and save the mesh Preparation Step 1 Creating Parts ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 63 Hexa Mesh Generation for a 3D Pipe Junction Step 2 Creating a Material Point Step 3 Blocking the Geometry Step 4 Projecting the Edges to the Curves Step 5 Moving the Vertices Step 6 Generating the Mesh Step 7 Checking the Mesh Quality Step 8 Creating an O Grid in the Blocking Step 9 Verifyin
77. Select 4 Select items in a part in the Select blocking face toolbar that appears or type Shift P on the keyboard This will open the Select Blocking parts dialog box and will allow you to select the faces c Retain the default settings and click Apply in the Ogrid Block DEZ In Figure 61 Blocking with the O Grid Structure p 83 the O Grid passes through the selected faces The radial blocks are adjacent to the cylinder surfaces ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 82 formation of ANSYS Inc and its subsidiaries and affiliates Step 8 Creating an O Grid in the Blocking Figure 61 Blocking with the O Grid Structure 3 Modify the O Grid Blocking gt Edit Block amp gt Modify Ogrid Fz Edit Block Edit Block Seid ye Sa Ne Modify OGrid Method Rescale Ogrid i Rescale Ogrid Block Select AllVisible C Selected Edge 123 30 A I Absolute distance Offset fos Apply Dismiss a Retain the selection of Rescale Ogrid in the Method drop down list b Retain the selection of All Visible for Block Select ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 83 Hexa Mesh Generation for a 3D Pipe Junction c Click Select edge s and select the radial edge shown in Figure 62 Edge Selected for Modify
78. Surfaces Geometry Surfaces Wire Frame Set the part parameters Mesh gt Part Mesh Setup a Part Mesh Setup 17 Show sme params using scale tector F Apply inflation parameters to curves I Remove inflation parameters trom curves a Enter 0 5 for max size for CUBE b Enter 1 for max size for both SPHERE and SYMM c Enter 0 01 and 0 02 for height for CUBE and SPHERE respectively Enter 1 2 for height ratio for both CUBE and SPHERE m Click Apply and then Dismiss in the Part Mesh Setup dialog box View the sizes set Figure 76 Hexa Mesh Sizes p 104 Geometry Surfaces Hexa Sizes ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 103 Hexa Mesh Generation for a Sohere Cube Geometry Figure 76 Hexa Mesh Sizes Update the mesh Blocking gt Pre Mesh Params Update Sizes a Retain the selection of Update All in the Method list b Click Apply c Enable Pre Mesh Blocking Pre Mesh The Mesh dialog box will appear asking if you want to recompute the mesh Click Yes d Disable Edges under Blocking Surfaces and other entity types under Geometry in the display control tree Blocking Edges Geometry Surfaces e Select Solid amp Wire for the Pre Mesh display Blocking Pre Mesh Solid amp Wire The initial mesh is shown in Figure 77 Initial Mesh p 105 104 AN
79. TA_6 g Click Apply The quality histogram will be updated accordingly Figure 211 Histogram Quality After Smooth ing p 278 Figure 211 Histogram dQuality After Smoothing 138024 103518 69012 34506 0 I I 1 1 1 1 1 1 1 D o tie se ich Hon Ueo Te Uh ea 9 Check the mesh for any errors that may cause problems during the analysis ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 278 formation of ANSYS Inc and its subsidiaries and affiliates Step 4 Generating the Delaunay Mesh Edit Mesh gt Check Mesh Check Mesh P Check Mesh Error Possible Problems M Duplicate element MV Multiple edges MV Uncovered faces V Triangle boxes JV Missing internal faces 2 single edges Periodic problems I Single multiple edges IV Volume orientations Stand alone surface mesh MV Surface orientations V Single edges V Hanging elements Delaunay violation Penetrating elements Overlapping elements Disconnected bar MV Non manifold vertices elements V Unconnected vertices Set defaults Elements to check Al Active parts Check mode Create subsets Check fix each a Retain the default set of checks b Click Apply to check for errors and possible problems in the mesh Make sure no errors problems are reported during the check Step 4 Generating the Delaunay Mesh In this step you will replace the
80. Walls Figure 158 Blocking after Internal and External Edge Association o y N V LNU AAV E A a a ZN WF af A IA ANA A LY x ZN KZ WA AS VN V Y M Z AA i Lh CFSE a PS ZO VAAN AA yo NV 4 A AY i In Figure 158 Blocking after Internal and External Edge Association p 203 Internal Edges and Curves have been disabled to reduce screen clutter to better see where edges have been associated to curves Resolve Zero Thickness Walls In this sequence blocking faces are associated with geometry surfaces representing the parts Shell Plate and Plate2 By making these associations the mesh will respect these internal surfaces boundaries 1 To reduce screen clutter set the values of index control as shown in the following table ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 203 Bottom Up Hexa Mesh Strategy for a Grid Fin Display the front view View gt Front Associate the faces to part PLATE1 Blocking gt Associate amp gt Associate Face to Surface a In the Method list ensure Part is selected b Click amp Select face s The Select Blocking face toolbar will appear Figure 159 Select Block face toolbar with Toggle All enabled SERRE a
81. ack sections in this model then attempt a swept mesh in the unstructured regions fails in the model and finally fills the remaining volume with the default unstructured fill Tetra in the this example Create Block Part FLUID ba T Inherit Part Name Create Block ggwa SVVBiew 2D to 3D Method Multone Fill V Create Ogrid around faces Surface Parts DUCT amp Bese Offset distance fo 86688 Fill Type Method Advanced 6 Click Apply The completed 3D Mesh is shown ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 311 Multizone Mesh in HVAC Square to circle Transistion Duct Figure 233 Completed 3D Blocking for HVAC Transition Duct In the Display tree under Geometry disable Curves and Surfaces under Blocking disable Edges and right click Pre Mesh and choose Solid amp Wire Zoom in to the curved end of the duct to observe the inflation layers on the duct surface and the O grid structure of the blocking ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 312 formation of ANSYS Inc and its subsidiaries and affiliates Checking the Mesh Saving and Exiting Figure 234 O Grid structure and Boundary Layer Detail Checking the Mesh Saving and Exiting The 3D volume mesh is examined and modified before finishing up
82. affiliates Build the Hexa Core mesh Figure 178 Quality Histogram for Tetra Prism Mesh after Smoothing 0 1 I l l I l 1 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 Find data for Mesh comparison Info gt Mesh Info Scroll through the message window to find the number of elements in the FLUID part the tetra and prism volume elements belong to this part You should see a number greater than 700 000 Save the Project File gt Save Project Build the Hexa Core mesh In this sequence tetra mesh elements that are not close to any geometry features are replaced with hexa elements reducing the total number of elements 1 Enable Hexa Core meshing Mesh gt Compute Mesh gt Volume Mesh W a For Mesh Type select Tetra Mixed from the drop down list b For Mesh Method select Quick Delauney from the drop down list c Enable Create Hexa Core Disable Create Prism Layer d Under Input select Existing Mesh from the drop down list e Enable Load mesh after completion f Click Compute This will replace the core volume elements with Hexa elements of a size 4 0 as set earlier See Figure 179 Cut Plane View of Hexa Core Mesh p 230 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 229 Tetra Prism Mesh in a Fin Configuration Figure 179 Cut Plane View of Hexa Core Mesh
83. and 21 indicate association to a fixed point With Curves enabled Create an O grid and Place Vertices In this sequence you will split the block into an orthogonal grid and then move the vertices into position for better quality mesh generation 1 Create the O grid Blocking gt Split Block gt Ogrid Block a Click S amp S Select Block s and then select the only block b Click the middle mouse button to accept the selection Click AN d Click the middle mouse button to accept the selection Select Edge s and then select the edges 11 19 and 19 21 See Figure 143 Selection of Block and Edges for O grid creation p 185 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 184 formation of ANSYS Inc and its subsidiaries and affiliates Create an O grid and Place Vertices Figure 143 Selection of Block and Edges for O grid creation e Click Apply The blocking after O Grid creation is shown in Figure 144 Blocking after O grid creation p 185 Figure 144 Blocking after O grid creation ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 185 Bottom Up Hexa Mesh Strategy for a Grid Fin 2 Associate mid edge vertices Blocking gt Associate amp gt Associate Vertex oe a In the Entity selection box
84. are already defined in the geometry tin file Then the periodic relationship is applied to block faces and ensures that a node on the first boundary has identical R and Z coordinates to the corresponding node on the second boundary The user is prompted to select corresponding vertices on the two faces in sequence When all vertices on both flow boundaries have been selected a full periodic relationship between the boundaries has been generated ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 207 Bottom Up Hexa Mesh Strategy for a Grid Fin 1 Check define the periodic parameters Mesh gt Global Mesh setup Kia gt Set up Periodicity Figure 164 Periodicity Set Up DEZ Global Mesh Setup Global Mesh Parameters BELLY Set up Periodicity V Define periodicity Periodicity Type Rotational periodic Translational periodic Rotational axis Method User defined by angle Base 000 Axis foot Angle 20 Base is a point through which the axis of rotation passes in this case it is the origin Axis is a vector that defines the axis of rotation in this case parallel to the z axis Angle defines the extent of the computational domain around the axis of rotation 360 represents on full rotation In this example Angle should be 20 degrees 2 In the Display tree enable the di
85. at each blocking edge is associated to the named curve s ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 10 formation of ANSYS Inc and its subsidiaries and affiliates Step 2 Associate Entities to the Geometry Figure 9 Display Showing Vertex Numbers and Curve Names URVES 6 Blocking gt Associate amp gt Associate Edge to Curve CS Blocking Associations Ea Edit Associations a BOSC KDX Associate Edge gt Curve Edges Kaio OS amp Ses Curve s cURVESA amp ees Project vertices Project to surface intersection Project ends to curve intersection a Apply E Dismiss 1 Associate the inlet the left most end of the large pipe a Ensure that Project Vertices is disabled b Click Select edge s and select edge 13 41 Click the middle mouse button to accept the se lection ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 11 Hexa Mesh Generation for a 2D Pipe Junction c Click amp Select compcurve s and select CURVES 1 Click the middle mouse button to accept the selection d Click Apply The associated edge will be colored green Note If Auto Pick Mode is enabled this operation will run in continuation mode allow ing you to select the next set of edges an
86. ate a density box of size 32 Mesh gt Create Mesh Density P Create Density Q Name density Sehj2 o Roo oo wda oo Density Location gS e e f C Points Entity bounds Apply __OK Dismiss a Disable FF and BIGSYM in the display control tree b Enter 32 for Size c Select Entity bounds for Density Location ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 253 Tetra Prism Mesh Generation for a Helicopter d Click Select geometry and then Select all appropriate visible objects in the selection toolbar e Click Apply in the Create Density DEZ A density box will be created around the fuselage Figure 194 Density Box Around the Fusel age p 254 Figure 194 Density Box Around the Fuselage mEn amaii 4 Move the density box to the rear end of the fuselage Geometry gt Transform Geometry gt Translate Geometry r Transformation Tools 9 Select density density 0 us Translate Rotate Mirror Scale Bo gia A Translate l Copy L as Translation Method Explicit x Offset fian Y Offset fo Z Offset fo Apply foe Dismiss a Select P Measure Distance from the utilities and measure the length of the aircraft The length of the aircraft is around 2422 b Click Select geometry and select the density box in the g
87. ber of nodes to 20 Ensure Copy Parameters is enabled and To All Parallel Edges is selected in the Method list Recompute the mesh Check the quality of the mesh Blocking gt Pre Mesh Quality Histogram vi vii Ensure that Determinant 2x2x2 is selected in the Criterion drop down list Retain 0 for Min X value and 1 for Max X value Retain 0 for Max Y height and 20 for Number of bars Ensure that Only visible index range is disabled Enable Active parts only Click Apply Select the lower value bars to see the skewed cells Figure 138 Worst Cells After Adding Cells p 170 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 169 Hexa Mesh Generation for an Elbow Part Figure 138 Worst Cells After Adding Cells BDetermin l 1 1 M Mi ceertoe nh Maree Laser D ks Ocoee LLG 1 Qo The element quality has improved and there are fewer elements in the lower bars of the his togram The cells which now remain appear to have poor internal angles and could be im proved by adjusting the blocking to improve these angles Adjusting the blocking too far could result in other cells on the other side of the moved vertex worsening You could tweak to further improve this mesh but it is more than high enough to give good results in any com mercial solver You will always have worst elements but if the
88. bled 90 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 1 Creating Parts 4 5 e Select the four symmetry surfaces at the bottom of the geometry and click the middle mouse button to accept the selection f Click Apply in the Create Part DEZ The new part SYMM will be added to the display control tree Similarly create new parts for the sphere SPHERE and the cube CUBE as shown in Figure 66 Sphere Cube Parts p 91 Figure 66 Sphere Cube Parts SPHERE Delete the curves Geometry gt Delete Curves X a Click amp Select curve s and then x Select all appropriate objects in the Select geometry toolbar to select all the curves b Ensure that Delete Permanently is disabled Note When Delete Permanently is disabled the deleted curves become dormant In a later step when you use Build Topology these original curves will be used as opposed to surface extracted curves c Click Apply Delete the points ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 91 Hexa Mesh Generation for a Sphere Cube Geometry Geometry gt Delete Points X a Click x Select point s and then x Select all appropriate objects in the Select geometry toolbar
89. ck You can remove the central block because the mesh will only be generated in the volume between the SPHERE and CUBE Very often when multiple blocks are displayed it is difficult to select the icon repres enting the block s An alternative method is to select the block by selecting a pair of diagonally opposing corners Blocking gt Delete Block Pad The Select Blocking block toolbar will appear a Select Toggle select diagonal corner vertices In the Select Blocking block toolbar Alternatively you can type Shift D on the keyboard b Select the two corner vertices as shown in Figure 75 Deleting the Block p 102 and click the middle mouse button to accept the selection Figure 75 Deleting the Block Note You can also simply select the central block from the screen This option is used here mainly for demonstration purposes as it may be useful in situations where many blocks exist and individual selection could be difficult c Ensure that Delete permanently is disabled d Click Apply to delete the block ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 102 formation of ANSYS Inc and its subsidiaries and affiliates Step 8 Generating the Mesh Step 8 Generating the Mesh 1 Disable the display of blocking edges and vertices Blocking Edges Blocking Vertices Enable the display of surfaces and select Wire Frame display Geometry
90. ck Apply e Enable Pre Mesh Blocking 18 gt pre Mesh The Mesh dialog box will appear asking if you want to recompute the mesh Click Yes 2 Match the edge spacing automatically Pre Mesh Params Meshing Parameters sa GON N Match Edge spacing Method Automatic vertices 3337 414243487 WR Spacing Minimum v Match Edges Dimension Selected All Ref Edges 1334 1 4234 AQ z Apply Dismiss a Select Automatic from the Method drop down list b Ensure that the Spacing is set to Minimum c Click Select vert s and then Select all appropriate visible objects from the Select Blocking vertex toolbar Alternatively with the mouse in the display window you can enter v for all visible vertices or drag a box to select all vertices d Click a Select edge s for Ref Edges select the edges 13 34 and 34 42 and click the middle mouse button to accept the selection This selection chooses the i and j index at each vertex for matching e Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 26 formation of ANSYS Inc and its subsidiaries and affiliates Step 7 Match the Edges f Disable and then enable Pre Mesh to recompute the mesh Blocking me pre Mesh The Mesh dialog box will appear asking if you want to recompute the mesh Click Yes Figure 17 Mesh Before Matching Edges p 27 an
91. ck mode is enabled selecting Move Vertex from the function tabs will prompt you to select from the screen It is usually not necessary to select Move Vertex from the DEZ unless another option was previously selected Click Select vert s and move the vertices of the inlets and the outlet as shown in Fig ure 11 Moving Vertices of the Inlets and Outlet p 15 Select the vertex and keeping the left mouse button pressed drag the vertex along the curve ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Move the Vertices Figure 11 Moving Vertices of the Inlets and Outlet Note Due to the associations made between the edges and curves many of these vertices will snap to the correct position Vertices may however be moved along the curve by dragging the mouse To capture the ends of the curves a Select the vertex and drag it with the left mouse button depressed until the vertex can be moved no further b Position the cursor beyond the end of the curve to ensure that the end is captured You may also prefer to associate the vertex with the points at the ends of the curves as described later Note The ends of the pipe are straight and it is possible to block this example without using the curve associations However the curve associations also create line ele ments on the
92. cks and then enable Solid block display and disable Whole blocks display Blocking me Blocks Blocking Blocks Solid Blocking Blocks Whole blocks 4 Set the Index control values as shown in the following table ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 198 formation of ANSYS Inc and its subsidiaries and affiliates Refine the Blocking with Further Splits and Associations 5 Figure 155 Blocks after Split around the Hub Part Delete the two blocks for the Hub part Blocking gt Delete Block 2 a Ensure that Delete permanently is disabled Click Q Select block s and then select the two middle blocks Click the middle mouse button to accept Click Apply Deleting blocks with Delete permanently disabled simply moves blocks to the reserved part VORFN These blocks can later be retrieved by enabling VORFN part and moving to a different part name The nodes count on edges will remain linked across the deleted block Deleting blocks with Delete permanently enabled will disconnect blocks in the VORFN region allowing different nodes count to be set on edges across this deleted block But it will also cause VORFN to be rebuilt and a recalculation of the indices on all vertices This can create a complicated index scheme which may cause problems further along in the blocking process It is also used to fix index problems that alrea
93. created only as a means to position the vertices precisely Note To identify the location of the Shell part enable Surfaces in the Display tree and then dis able enable Shell under Part 1 Disassociate from the geometry Blocking gt Associate amp gt Disassociate From Geometry D a Click Select vert s and then select all vertices Use a selection box or click Select all appropriate visible objects or press v b Click a Select edge s and then select all edges c Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 187 Bottom Up Hexa Mesh Strategy for a Grid Fin In the Display tree temporarily disable the display of Curves and Points to confirm that the color of edges and vertices has changed to blue indicating they are no longer associated with any geometry entities Rotate Copy the blocking BH Blocking gt Transform Block av gt Rotate Block a b Enable Copy Set the Number of copies to 3 For Rotation select Z from the Axis drop down list Ensure that the Angle is 90 For Center of Rotation select User s Point from the Center Point drop down list Click amp Select location s and then select POINTS 17 the center point of the grid Click the middle mouse button to accept your location selection Click R Select block s an
94. ct all appropriate visible objects in the Select geometry toolbar All the inlet and outlet surfaces will be selected c Select Create New in the Extract Edges list a Click Apply Enable AORTA_WALL in the Parts section of the tree Parts AORTA_WALL mi Select WireFrame Simple Display to restore the wireframe display ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 269 Tetra Prism Mesh Generation for an Aorta Step 2 Creating the Material Point Geometry gt Create Body F Create Body 9 Part FLUID gt g Material Point Location Centroid of 2 points C At specified point 2 screen locations E 85 88587369407 1 EN setts Apply Ee Dismiss 1 Enter FLUID for Part 2 Retain the selection of Centroid of 2 points for Location 3 Click amp Select location s and select two locations such that the midpoint lies within the volume see Figure 206 Selection of Points for Creating Material Point p 270 Click the middle mouse button to accept the selection of the points Figure 206 Selection of Points for Creating Material Point locations selected for creating the material point 4 Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 270 formation of ANSYS Inc and its subsidiarie
95. ction is simplified by enabling only curves points in the Display tree and then using Select all appropriate visible objects 4 Define a Material Point ted fatPi Geometry gt Create Body gt Material Point a For the Part name enter LIVE b Click amp Select location s and then select two locations on the PORT such that their midpoint is inside the PORT ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 237 Tetra Mesh in a Piston Valve Assembly c Click the middle mouse button d Click Apply Dynamically rotate the model to confirm that LIVE is located within the geometry and not outside the geometry Figure 185 Piston Valve Geometry with all Parts Named Setting Mesh Parameters In this sequence you will establish mesh parameters based on geometry types paying special attention to regions where small radius of curvature or thin cuts may cause problems when generating the mesh 1 Create Global Mesh parameters Mesh gt Global Mesh Setup Ka gt Global Mesh Size 6 a For the Scale factor enter a value of 0 6 b For the Max element enter a value of 128 c Enable Curvature Proximity Based Refinement ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 238 formation of ANSYS Inc and its subsidiaries and affiliate
96. d Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 261 Tetra Prism Mesh Generation for a Helicopter Figure 201 Zoomed in Cut Plane in Wake Region for Delaunay Mesh 4 Check the mesh for any errors that may cause problems during the analysis Edit Mesh gt Check Mesh Step 5 Smoothing the Mesh In this step you will smooth the mesh to improve the quality The smoothing approach involves initial smoothing of the interior elements without adjusting the prisms After initial smoothing you will smooth the prisms as well Edit Mesh gt Smooth Mesh Globally Smooth Elements Globally Q E Ce ee EEEE EE ga Smoothing iterations 5 al Up to value fos Criterion Quality 7 Smooth Mesh Type Smooth Freeze Float TETRA 4 g a TRI_3 O g 5 PENTA 6 co C QUAD 4 r C Smooth Parts Subsets Method All parts X Refresh Histogram oo apply OK Dismiss The quality histogram appears in the right hand corner ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 262 formation of ANSYS Inc and its subsidiaries and affiliates Step 6 Saving the Project 1 Smooth the interior elements without adjusting the prisms a Enter 25 for Smoothing iterations b Enter 0 5 for Up to value c Retain the selection of Quality for Criterion d Select Freeze for PENTA_6 Note The PENTA_6
97. d Figure 18 Mesh After Matching Edges p 27 show the mesh before and after matching the edges respectively Figure 17 Mesh Before Matching Edges 4 4 lt ES eC SS a oo Figure 18 Mesh After Matching Edges SS 4 ne SE SSS SEES SEER lt ORS Nat 3 Check the quality of the mesh Blocking gt Pre Mesh Quality Histograms Q ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 27 Hexa Mesh Generation for a 2D Pipe Junction Pre Mesh Quality Q Criterion Determinant 3x3x3 gt Min overview Histogram Options Minx value fo Max value f Max V height fo F Only visible index range Active parts only a Retain the default settings and click Apply b Select the worst two bars from the histogram The selected bars will be highlighted in pink Figure 19 Pre Mesh Quality Histogram p 28 Figure 19 Pre Mesh Quality Histogram Determinant 3x33 The worst quality elements in the mesh will be highlighted Figure 20 Elements With Worst Qual ity p 29 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 28 formation of ANSYS Inc and its subsidiaries and affiliates Step 8 Verify and Save the Mesh and Blocking Figure 20 Elements With Worst Quality
98. d confidential in 178 formation of ANSYS Inc and its subsidiaries and affiliates Associate Initial Blocking to a Minor Geometry Figure 140 Initial 2D Blocking Note By design 2D blocking is created only in the XY plane If the 2D part of your geometry is not parallel to the XY plane it is recommended to reorient the geometry to make it so Later in the process vertex movement and z direction extrusion may be difficult without this orientation Associate Initial Blocking to a Minor Geometry The initial blocking surrounds the extents of the geometry Here in keeping with the bottom up approach it is collapsed to fit a small portion of the geometry that resides in the x y plane 1 In the Display tree Enable display of Vertices by Number and Enable display of Points by Name Blocking me vertices Blocking Rue gt vertices DEH Numbers Geometry e points Geometry Re points Show Point Names 2 Associate Vertex 21 to point POINTS 3 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 179 Bottom Up Hexa Mesh Strategy for a Grid Fin Blocking gt Associate amp gt Associate Vertex oe Blocking Associations e Edit Associations z BOET RORY F C Self Point C Curve Surface Vertex 21 oe Point POINTS 3 Pee I Apply OK Dismiss a Ensure t
99. d contain only shell elements and the Edges branch should contain only curve elements and so on However if a part has a mixture of surfaces curves and points then the mesh will contain a mixture of element types and the part will be located in the Mixed unknown branch of the tree If you apply wall properties these are applied to the shells in that part only 4 Write the input file for ANSYS FLUENT Output gt Write input mi a Select the appropriate uns file The ANSYS Fluent dialog will appear ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 285 Tetra Prism Mesh Generation for an Aorta ANSYS Fluent Please edit the following ANSYS Fluent options Grid dimension 3D C 2D Scaling Yes No x scaling factor 0 001 y scaling factor fo 001 z scaling factor o oo Write binary file C Yes No Ignore couplings Yes No Boco file aorta foc Output file aorta Done Cancel b Select Yes for Scaling and enter 0 001 for x scaling factor y scaling factor and z scaling factor respectively The mesh was created in units of millimeters mm and hence needs to be scaled to meters c Retain the default settings for other parameters d Enter aorta for Output file e Click Done Note You can read the saved mesh file in ANSYS FLUENT and proceed to setup
100. d curves without re invoking the function Clicking the middle mouse button when no entities are selected or clicking Dismiss will cancel the function Similarly associate the following edge curve combinations to make the T fit the geometry Entity Edges Outlet top horizontal end of large pipe 21 44 Small pipe 33 42 33 37 37 43 Sides of large pipe 13 34 34 38 38 CURVES 2 CURVES 5 21 CURVES 6 41 42 43 44 CURVES 3 CURVES 4 CURVES 8 Note When entities are overlapped with other entities disabling certain entity types in the Model tree will help to identify the right entity For example disable Vertices and Edges to verify the curve names Enable the Edges to proceed with the selection Note For the edges defining the sides of the pipe select all the edges first before clicking the middle mouse button to confirm the selection Next select the curves and then click the middle mouse button again The curves will automatically be grouped as one logical composite entity Verify that the correct associations have been set see Figure 10 Association of Edges to Curves p 13 m Blocking Rue gt Edges e show association ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Move the Vertices Figure 10 Association of Edge
101. d then select all blocks Click Apply The blocking after the Rotate Copy transformation is shown in Figure 146 Blocking after Rotate and Copy p 189 188 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Complete the 2D Grid by Vertex Placement Figure 146 Blocking after Rotate and Copy Complete the 2D Grid by Vertex Placement In this sequence you will manually create blocks to extend the blocking from the central Shell part to the limits of the geometry The extents of a new block are defined by selecting four corner points starting with existing vertices and ending with points on the boundary of the geometry In the Display tree enable Edges and Vertices under Blocking and Curves under Geometry Disable Points 1 Create the first block Blocking gt Create Block Z gt From Vertices Faces w Retain the default settings Ensure that Part name is set to LIVE default a Click Select vert s and then select the vertices 11 and 13 in that order b Click middle mouse button to accept the selection As the two more positions need to be selected it remains in geometry selection mode c Select two locations in the same order shown by 0 and 1 in Figure 147 Vertices and Points selected for First Block p 190 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains pro
102. dges in the Display tree See Figure 85 Edge to Curve Associations for the Pipe p 118 Blocking Edges Show Association ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 117 Hexa Mesh Generation for a Pipe with Embedded Blade Figure 85 Edge to Curve Associations for the Pipe Note If the edges lie on the geometry as is the case with longitudinal edges the projection arrows are not shown By default all external edges are surface associated to the nearest active surface and appear as white black if a light background Should any Edge to Curve association mistakes occur the association can be set to using Blocking gt Associate amp gt Associate Edge to Surface E 5 Group curves optional Note Curves are automatically group when multiple curves are selected for making an associ ation This step may be used to manually group curves Blocking gt Associate gt Group Ungroup curves a a Click R Select curve s or compcurve s and then select the curves to be grouped For example the four curves that define the OUTLET b Click Apply to group them All curves will be the same color ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 118 formation of ANSYS Inc and its subsidiaries and affiliates Splitting and Collapsi
103. dle mouse button to accept the selection See Figure 171 Part names for External Surfaces p 220 f Click Apply to complete the part creation ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 219 Tetra Prism Mesh in a Fin Configuration Figure 171 Part names for External Surfaces SYMM OUTLET INLET Note Surface colors are assigned when the part name is applied g Similarly create parts for OUTLET SYMM and BOX 3 Create Surface parts for the Fin geometry Create parts for LEAD PRESS the lower surface of the fin SUCT the upper surface TIP and TRAIL as shown in Figure 172 Part names for Fin Surfaces p 221 Tip You may find it useful to disable the display of curves and previously created surface parts when creating these surface parts on the fin geometry ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 220 formation of ANSYS Inc and its subsidiaries and affiliates Setup Mesh Parameters Figure 172 Part names for Fin Surfaces Note Curves and Points will remain in the GEOM part which is simplest for this tutorial In practice you may want to add the curves and points into parts along with the surfaces Create a Material point for the volume region that lies within the BOX surrounding the
104. dy exist since it forces a recalculation of indices ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 199 Bottom Up Hexa Mesh Strategy for a Grid Fin Figure 156 Hub Blocks Deleted 6 In the Index Control panel click Reset and then click Done 7 Inthe Display tree disable Blocks and Points and enable Show Curve Names 8 Associate edges around the Hub To resolve the HUB accurately you need to associate the edges lying on the top of the curves Blocking gt Associate amp gt Associate Edge to Curve CG a Click amp Select compcurve s and then select the curve CURVES 31 See Figure 157 Four curves for Association around the Hub p 201 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 200 formation of ANSYS Inc and its subsidiaries and affiliates Refine the Blocking with Further Splits and Associations Figure 157 Four curves for Association around the Hub b Click the middle mouse button to accept You may find it useful to disable Curves while selecting Edges and vice versa c Click Select edge s and then select the edge that lies on top of CURVES 31 d Click the middle mouse button to accept e Click Apply to complete the association When an edge becomes associated with a curve it is colored green You should confi
105. e If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Throughout this and other tutorials Parts Points Curves and Surfaces may be made visible or turned off as necessary to assist in describing the steps of the tutorial Typically the default settings for visibility are sufficient for most work and such steps are used only to isolate spe cific parts for specific tasks ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 218 formation of ANSYS Inc and its subsidiaries and affiliates Create Surface and Material Parts Create Surface and Material Parts In this sequence you will create Parts and a Material point assigning geometry surfaces and a volume region to them 1 In the Display tree under Geometry under Curves disable the display of Show Wide 2 Create Surface parts for the extents of the geometry Parts Create Parts For the Part name enter INLET bo Ensure Nw Create Part by Selection is selected a c Click Select entities d In the Select geometry toolbar toggle OFF Selection of Points x Curves K and Bodies dl e Click to select the surface for the INLET part and then click the mid
106. e CAR Vehicle geometry GROUND Lower limit of the wind tunnel INLET Where flow enters the wind tunnel In this example it is the left side limit of the geometry OUTLET Where flow exits the wind tunnel PNTS Prescribed points associated with the Car TOP Upper limit of the wind tunnel Note This geometry contains only curves and points Surfaces are helpful but not necessary for 2D meshing Activate the Replay Control function A Replay file will be created and then used on the modified geometry car_mod tin The same part and entity names are used in both the base and modified geometries which allows the Replay file to be run without editing on the modified geometry File gt Replay Scripts gt Replay Control 32 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Start a New Project and Initiate Replay Control r Replay control iS E 2s Operations in script J wie V Record after current All commands Do one Do all Load Do range Save Edit Insert Delete one Delete all Delete range Renumber Always update Ignore errors Done Note The replay function allows you to record the steps necessary to complete the mesh The Replay Control window may be moved aside or minimized while recording but the window should be kept act
107. e Delaunay Mesh Step 5 Saving the Project Further Setup ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 265 Tetra Prism Mesh Generation for an Aorta Preparation 1 Copy the input geometry file Aorta st1 from the ANSYS installation directory under v145 icem cfd Samples CFD_Tutorial_Files Aorta to the working directory Start ANSYS ICEM CFD and import the geometry Aorta st1 File gt Import Geometry gt STL a Select the STL file Aorta st1 in the Open dialog box and click Open The STL import options dialog will appear STL import options STL file options Part names Generate From file Done Cancel Retain the selection of Generate for Part names and click Done The imported geometry will be displayed in the graphics window Select Solid Full Display from the Solidframe Display Options menu Figure 204 The Aorta Geometry Note If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail 266 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS
108. e objects Note In this example it may be easier to select the symmetry plane surface using a single left button click For complex models which have more surfaces it will be easier to use Select all appropriate visible objects or Select items in a part or even the box selection c Click Apply Step 2 Creating a Material Point Geometry gt Create Body F 250 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 2 Creating a Material Point Create Body Q Part FLUID yi Material Point Location Centroid of 2 points At specified point 2 screen locations 262 81 8738822 R apply OK Dismiss 1 Enter FLUID for Part 2 Ensure that Points is enabled in the display control tree 3 Retain the selection of Centroid of 2 points for Location 4 Click amp Select location s and select two locations such that the midpoint lies within the volume one on the symmetry surface and other on the far field surface see Figure 193 Selection of Points for Creating Material Point p 251 Click the middle mouse button to accept the selection of the points Figure 193 Selection of Points for Creating Material Point ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and aff
109. e the mesh quality within the main elbow pipe and also provide a boundary layer Blocking gt Split Block gt Ogrid Block 1 Ensure that both SOLID and FLUID are enabled in the display tree You enabled SOLID at the end of the previous step Unless both SOLID and FLUID are enabled the O Grid will also wrap the valve stem small cylinder which is also valid but may require additional mesh editing to get good quality Create the O Grid a b Click Select Block s and select all the blocks by box selecting over the entire model Add the faces on the inlet and outlet i Click Select Faces and select all the faces on the INLET and OUTLET as shown in Fig ure 126 Blocks and Faces Selected for the O Grid p 160 Figure 126 Blocks and Faces Selected for the O Grid There are five faces on the OUTLET part and one face on the INLET part If you select the wrong face deselect it by clicking again using the right mouse button You can also select 2 the faces by clicking the amp icon in the Select Blockingface toolbar This toolbar appears 160 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 7 Creating the Second O Grid when you click the Select Faces icon Select INLET and OUTLET in the Select Blocking parts dialog box In addition select the center face on the OUTL
110. ect file Open the modified geometry car_mod tin a ANSYS ICEM CFD users i Initiate a new ANSYS ICEM CFD session ii File gt Geometry gt Open Geometry b ANSYS Workbench users i Close the Mesh Blocking and Geometry File gt Mesh gt Close Mesh File gt Blocking gt Close Blocking File gt Geometry gt Close Geometry ii Open the modified geometry File gt Geometry gt Open Geometry Note ANSYS Workbench users All files associated with your project are saved together in a folder with the same name as your Workbench project By closing the Mesh Blocking and Geometry without exiting the ICEM CFD environment you will more easily locate and use the replay file However by opening a new Geometry the Blocking and Mesh files will be recreated overwriting the previous ones Alternatively to preserve the base Geometry Blocking and Mesh within your project you may create a second ICEM CFD component in your Workbench Project schematic and then open the modified geometry there Since the replay script is associated with the first ICEM CFD component you will need to navigate your OS folder hierarchy to find it 58 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Save the Replay File and Use it for Design Iteration In car_mod tin the trunk or deck lid is extended rearward t
111. ect files File gt Save Project Close the project File gt Close Project Exit the program File gt Exit ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 245 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 246 formation of ANSYS Inc and its subsidiaries and affiliates Tetra Prism Mesh Generation for a Helicopter This tutorial demonstrates the generation of the Tetra Prism mesh for a helicopter The far field used in the tutorial is smaller than normal to reduce the runtime Figure 191 Helicopter Geometry This tutorial demonstrates how to do the following Extract feature curves from the symmetry plane Create the material point Generate the Octree mesh e Manipulate the mesh display using cut planes Generate the Delaunay mesh e Smooth the mesh ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 247 Tetra Prism Mesh Generation for a Helicopter e Verify and save the mesh Preparation Step 1 Preparing the Geometry Step 2 Creating a Material Point Step 3 Generating the Octree Mesh Step 4 Generating the Delaunay Mesh Step 5 Smoothing the Mesh Step 6 Saving the P
112. eed to be considered It is always good to ensure the surface mesh is setup as well as possible before increasing complexity with further splits or O Grids Blocking gt Move Vertex gt Move Vertex S a Orient the model as shown in Figure 112 Moving the Vertices p 148 so that the cylinder edges overlap b Move the vertices to their new positions as indicated in Figure 112 Moving the Vertices p 148 Click on the vertex using the left mouse button and hold the button while you slide the vertex along the surface The vertices are moved to position the edge away from the cylinder curve ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 147 Hexa Mesh Generation for an Elbow Part Figure 112 Moving the Vertices es NI M ee A Before Moving Vertices B After Moving Vertices Figure 113 Moved Vertices lsometric View p 148 shows the blocking isometric view after the vertices have been moved Figure 113 Moved Vertices Isometric View Step 4 Creating the First O Grid This tutorial focuses on the flow outside of the internal pipe Thus in generating the first O Grid you will essentially partition the volume around the small internal pipe so that part of the blocking may be removed 1 Create the first O Grid Blocking gt Split Block gt Ogrid Block ANSYS ICEM CFD 14 5
113. egrees apart 180 half circle 3 edges 60 per edge 3 Save the blocking 3D pipe geometry b1k File gt Blocking gt Save Blocking As The blocking file can be reloaded at a later time using the File gt Blocking gt Open Blocking menu item Step 6 Generating the Mesh For this model you will set the sizes on the parts rather than on individual surfaces or curves 1 Set the sizes on the parts to generate the mesh Mesh gt Part Mesh Setup re ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 75 Hexa Mesh Generation for a 3D Pipe Junction Part Mesh Setup TS an E e ee Se ee eee fa fd 3 f E r i 9 e f seer 5 TT lest oe Show sze pases vang scale Lactor F Agoly nilson parameters to curves T Remora nilson parameters hom caves a Click the max size header The MAX SIZE dialog box will open MAX SIZE max size fio Accept Cancel b Enter 10 for max size and click Accept c Decrease max size for CYL2 to 5 d Enter 1 for height for CYL1 and CYL2 Enter 1 2 for height ratio for CYL1 and CYL2 mh Click Apply and then Dismiss in the Part Mesh Setup dialog box View the sizes set Geometry Surfaces Hexa Sizes In Figure 56 Hexa Mesh Sizes p 77 the quad along the surface represents the max size the thickness represents
114. element zones OGrid The remainder of the complex volume is filled by a variety of methods including mapped hexa blocks swept blocks or unstructured mesh zones which can be filled with a variety of unstructured methods available Where possible the MultiZone tool automatically subdivides the volume and can handle multi source amp target and multi direction sweeping based on the robust ICEM CFD Hexa blocking framework In addition ICEM CFD Hexa blocking tools Adjust Mesh distribution Move vertices Align verts Check quality Smooth etc are available to interactively improve the mesh as necessary This tutorial demonstrates how to do the following Prepare the Geometry Set up Global and Part Parameters Create Automatic Surface Blocking Convert the Surface Blocking to 3D Blocking Checking the Mesh Saving and Exiting Prepare the Geometry 1 Copy the input geometry file Duct Transition_Long tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files DuctTransition to the working dir ectory 2 Start ANSYS ICEM CFD and create a new project in your working directory Use an appropriate name for example Multizone_Hvac File gt New Project 3 Open the geometry file Duct Transition_Long tin File gt Geometry gt Open Geometry ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 305
115. ensity P a b Size 0 0625 Ratio 0 and Width 4 For the Density Location From choose Points Click amp Select location s and then select two points from the screen that define the surface LEAD Select one point at the base of the fin centered on the leading edge and one point at the tip of the fin also centered on the leading edge See Figure 173 Two Points on LEAD sur face p 223 Figure 173 Two Points on LEAD surface Click middle mouse button to complete the selection Click Apply Similarly create a Mesh Density region at the trailing surface of the fin ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 223 Tetra Prism Mesh in a Fin Configuration Figure 174 Fin with Density Regions added to Leading and Trailing Edges Note The density region is created as a cylindrical volume of radius Width x Size To control the growth ratio away from the density region set a value for Ratio Setting Ratio to o uses a default of 1 2 6 Set meshing parameters by Parts Mesh gt Part Mesh Setup ro In the Part Mesh Setup dialog box a Enable prism for the fin parts LEAD PRESS SUCT TIP and TRAIL b Enable hexa core for the material part FLUID c Set max size to 4 for the part FLUID d Select Apply and then Dismiss ANSYS ICEM CFD 14 5 SAS IP Inc A
116. eometry This tutorial demonstrates how to do the following Start a New Project and Initiate Replay Control Create and Split the Blocking to Resemble the Geometry Associate and Fit the Blocking to the Geometry Align the Vertices Set Mesh Parameters and Generate the Initial Mesh Create an O grid Refine the Mesh using Edge Parameters Save the Replay File and Use it for Design Iteration Create Output Data for a Solver Start a New Project and Initiate Replay Control 1 Copy the input geometry files car_base tin and car_mod tin from the ANSYS installation dir ectory under v145 icemcfd Samples CFD_Tutorial_Files 2DCar to the working directory 2 Initialize your project a ANSYS ICEM CFD stand alone users i Start ANSYS ICEM CFD ii Create a new project in your working directory Use an appropriate name for example 2D_Car_base File gt New Project b ANSYS Workbench users ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 31 Hexa Mesh Generation for a 2D Car i Create an ICEM CFD Component in your Project Schematic ii Double click the Model cell to open ICEM CFD Open the original unmodified geometry file car_base tin File gt Geometry gt Open Geometry The following Parts have been defined in the geometry Ensure that all the names of the listed Parts are available in the Display Tre
117. erify that the correct associations have been set Figure 70 Projection of Edges to the Associated Curves p 98 a Enable the display of surfaces and select the Solid display ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 97 Hexa Mesh Generation for a Sohere Cube Geometry Geometry Surfaces Geometry Surfaces Solid b Select Show association Figure 70 Projection of Edges to the Associated Curves p 98 Blocking Edges Show association Figure 70 Projection of Edges to the Associated Curves 6 Step 6 Moving the Vertices GA Blocking gt Associate gt Snap Project Vertices x 1 Disable Surfaces to better view the new vertex position Geometry Surfaces 2 Retain the selection of All Visible for Vertex Select 3 Click Apply Figure 71 Moving the Vertices p 99 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 98 formation of ANSYS Inc and its subsidiaries and affiliates Step 7 Creating the O Grid Figure 71 Moving the Vertices Step 7 Creating the O Grid In this step you will create an O Grid to capture the cube as well as radially propagate the mesh onto the sphere 1 Create the half O Grid Blocking gt Split Block gt Ogrid Block Z a Click R Select face s and select the bottom face of the block C
118. ersa Click Select edge s and then select any horizontal edge top or bottom edge Click x Select point s and then select PNTS 10 at the rear of the car Note At any point in time while in selection mode you can toggle to dynamic mode by pressing F9 or clicking C Toggle dynamics This may be necessary in order to zoom in to get a closer view of the points Pressing F9 again will toggle back to selection mode Click Apply The new edge will be created as shown in Figure 23 First Split p 38 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 37 Hexa Mesh Generation for a 2D Car Figure 23 First Split _ e lt a S 7 PTS 8 puss f pens 2 NPaiS 20 PNTS 15 IPuTS 14 NTS 11 ta iv Similarly make one more vertical split at the front of the car through point PNTS 1 d Also make two horizontal splits at the bottom and top of the vehicle PNTS 12 and PNTS 5 as in shown in Figure 24 First Block Splits at Car Extents p 38 Figure 24 First Block Splits at Car Extents 4 Split selected blocks using Index control By default splits propagate only through the displayed blocks By blanking blocks using Index control values the propogation of visible splits can be managed a Select Index Control Blocking EME index Control ANSYS ICEM CFD 14
119. ersection Apply Dismiss d Click Apply to complete the association e Similarly associate the remaining edges 13 21 21 19 and 19 11 to the curves TOP 1 OUTLET 1 and GROUND 1 f Disable the display of Curves in the Display Tree Ensure that all edges have turned green indicating a valid association g In the Display Tree re enable Curves disable Show Curve Names and disable Vertices Split the Initial Block using Prescribed Point method Blocking gt Split Block gt Split Block 36 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Create and Split the Blocking to Resemble the Geometry Set display parameters Ensure Curves and Edges are enabled default in the display tree showing the initial block Enable the display of Points and Show Point Names Geometry Ee points Geometry e points me show Point Names The name of the Points will appear on the screen I Zoom in to the rear bumper Change Split Method to Prescribed point in the Split Block DEZ This method is based on the location of a specific point and is more parametric than the default Screen select which is based on a percentage of the edge length Split the block vertically Splits are propagated perpendicular to a selected edge That is select a horizontal edge to make a vertical split and vice v
120. es ae ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 73 Hexa Mesh Generation for a 3D Pipe Junction Blocking Associations Edit Associations a woe er KVR S Snap Project Vertices Vertex Select AllVisible C Selected fe WS Move 0 Grid nodes a Apply ae Dismiss a Retain the selection of All Visible for Vertex Select b Click Apply 2 Manually move the vertices Blocking gt Move Vertex gt Move Vertex rad a Click Select vert s and select one of the vertices in green on the smaller cylinder b Move the vertex along the associated curve such that the edges along the smaller cylinder are nearly equidistant Drag the vertex along the curve keeping the left mouse button pressed c Similarly move the other vertices to appropriate locations on the geometry Figure 55 Moved Vertices p 75 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 74 formation of ANSYS Inc and its subsidiaries and affiliates Step 6 Generating the Mesh Figure 55 Moved Vertices Z Note To optimize mesh quality the vertices should be spaced to minimize the average deviation of the edges from the curve To achieve the most even distribution with this half cylinder case place the vertices approximately 60 d
121. esh Generation for a Pipe with Embedded Blade Figure 83 Vertex to Point Associations for the Pipe Note When possible and to achieve the best quality mesh Block vertices on any circular geometry should be placed so that edges are equal in length and the internal angles between edges are 90 degrees 4 Associate the block edges to curves on the geometry Blocking gt Associate amp gt Associate Edge to Curve e a In the Display tree disable the display of Points and Surfaces and enable the display of Curves Click Select edge s and then select the four edges of the blocking at the OUTLET end of the pipe Click the middle mouse button to accept Click amp Select compcurve s and then select the four curves around the OUTLET end of the pipe 116 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Initial Blocking and Associations Figure 84 Select Edges and Curves Select these edges Select these curves Click Apply to complete the association The edges turn green confirming their association Also notice the four curves become one color indicating that they have been grouped into a single curve Similarly associate the four edges at the INLET end of the pipe to the corresponding four curves To see a confirmation of the associations enable Show Association under E
122. essssreessseresssereesseeessssreesssresse 107 Hexa Mesh Generation for a Pipe with Embedded Blade 0 ccsessscccceceeesessnneeeceeecesseessnneeeeeeeens 109 Starting the Projecte a on erra erir ani aa a eE aen E o i eadar aa Te ana Ae aR Eei ien ta Oaa N ara 110 Creating Parts in the Mesh Editor sssessseseesssssessseseessssressssseesssetessssreesssstessssreesssetessseresssereessssreessseee 110 Initial Blocking and Associations nersini eiia a e k aaki aae 114 Splitting and Collapsing Blocks around the Blade ssssssssessesseesssssessssresssssressssressssrressseresssereessssressseee 119 Fit the Blocking to the Blade geometry sssssssssssesssssesssssressssreessseresssereesssreessssresssseressesressseteesssseeessene 123 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates iii Tutorials Generating the OGM xi csserastnenessane sweats i a a eaa a a a a a a a a a 126 Defining Surface Parameters for the Mesh essssccseessescesesseeceesesseeeeseesseceeseesenseesenseseessesseeeesensonse 128 Defining Edge Parameters to Adjust the MeSH js wicsiissscnsnasesiceunadesinstaversnannsasaieausanesererencnasntadsaeasnureuenantes 130 Checking and Improving Mesh Quality ics icariscicraicavecn aime aaa ania ein am anu ceadas 133 SAVING aveidarrind Aniide fend Aa e Sa E ESO EA ae E ed aan Bidders 136 Hexa Mesh Ge
123. ext and select Edit filter This shows the list of those commands that can be cleaned Note The replay file can contain all steps taken during the entire session some of which may be redundant or needed only during recording For example commands beginning with ic_undo are added by ICEM CFD while recording but do not contribute directly to the mesh creation process However they may be important in using the replay file if you had to backtrack during your session You may use the Clean gt Renumber sequence to remove extraneous commands and then number the commands properly but this is recommended only if you are certain that it will not cause replay problems Typically it is safer to save the longer replay file 3 Right click again to go back to the replay script 4 Disable Record after current ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 57 Hexa Mesh Generation for a 2D Car 5 6 Click Save and enter an appropriate filename For example 2DCar_Hexa_Ogrid_replay rpl Note The replay file may be used to build the block topology on a similar geometry or design iteration Instead of manually repeating the sequence of commands run the replay file ANSYS Workbench users All files associated with your project are saved together in a folder with the same name as your Workbench proj
124. filiates Merged Tetra Hexa Mesh in a Hybrid Tube In this tutorial you will generate a mesh for a Hybrid Tube This tube consists of three regions CYL1 CYL2 and CYL3 separated by two interfaces INTERFACE1 and INTERFACE2 The geometry is shown in Figure 214 Hybrid Tube Geometry showing Three Sections and Part Names p 289 The process will generate tetrahedral domains in CYL1 and CYL2 and a hexahedral domain in CYL3 The three domains will then be made conformal at the two interfaces The following are requirements for a successful merge You may select multiple surface mesh parts to merge The interfaces on both sides of the merge do not need to be in the same part although often that is easier to organize The merge function can handle many interfaces between two or more meshes including curved in terfaces However all the elements in the selected parts must be involved in the merge The perimeters of all the interface parts must be associated to curves that are aligned or even on the same curve on both sides of the interface e When two meshes are merged at least one must be tetra tri mesh Please see Merge Meshes in the Help document for more information Figure 214 Hybrid Tube Geometry showing Three Sections and Part Names cYLi ia oa a 7 sts A A f A f A AX A Ti X IX A IMA YA A A y OUTLET LY y A A h x A Tr INLET A V i A VI VA LA V
125. g and Saving the Mesh Preparation 1 Copy the input geometry file geomet ry tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files 3DPipeJunct to the working directory 2 Start ANSYS ICEM CFD and open the geometry geometry tin File gt Geometry gt Open Geometry Note If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Step 1 Creating Parts The geometry used in this tutorial is contained in a single part You will put the geometry into different parts to define different boundary regions 1 Enable Surfaces under Geometry in the display control tree 2 Create a new part for the largest semi cylinder Rue parts De create Part Create Part 9 Part CYL1 a be Create Part B2 Create Part by Selection Entities suface GEOM10 o F Adjust Geometry Names z Apply lai 3 Dismiss a Enter CYL1 for Part in the Create Part DEZ ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 64 formation of ANSYS Inc and its subsidiaries and affiliates Step 1 Creating Parts b Retain the selection of Nx Create Part by Selection and click R Select entities
126. g with a bottom up approach Since the Grid Fin geometry is primarily an extruded model in the Z direction we can then extrude the 2D blocking in the Z direction to create the 3D blocking More typically a top down approach in which you first capture the outer geometry and then split the blocks to capture the minor geometry is used However the flexibility of ICEM CFD Hexa to use either approach or a combination of both is very powerful and this tutorial will give you some insight The bottom up approach to blocking starts with a simple 2D Planar block In subsequent procedures it will be copied split and extruded to capture the full geometry 1 In the Display tree under Geometry ensure the display of Curves is enabled and Surfaces is disabled 2 Initialize the 2D Planar block Blocking gt Create Block Z gt Initialize Blocks ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 177 Bottom Up Hexa Mesh Strategy for a Grid Fin 6 Create Block Part LIVE T Inherit Part Name Create Block EKA ew Initialize Blocks Type Typa 2D Pons o Planar A Initialize with settings S Apply Lo Dismiss a Enter LIVE in the Part field b Change the Type to 2D Planar c Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary an
127. ges and Curves for Association b Click the middle mouse button to accept c Click amp Select compcurve s and then select the single curve closest to your selected edges d Click the middle mouse button to accept e Click Apply The edges turn green to indicate a successful association Similarly create Edge to Curve associations for the top and bottom of the blade on both sides Also associate the leading and trailing edges of the blade to the two curves added at the beginning of this tutorial In the Display tree enable Show Associations See Figure 91 Edges Associated to Curves on Blade p 125 Blocking Edges Show Association 124 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Fit the Blocking to the Blade geometry Figure 91 Edges Associated to Curves on Blade 5 Move all associated vertices to the geometry do Blocking gt Snap Project Vertices a a Ensure that All Visible is selected for Vertex Select b Click Apply All vertices move to the geometry In the Display tree disable the display of Vertices and Points enable the display of Curves Your blocking should appear as in Figure 92 Fully Split and Associated Blocking p 126 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its sub
128. ght over base EE Prism height limit factor Po Ratiomutipier SSS Prism element part controls New volume part N Side part A Top part 7 Extrude into orphan region Smoothing Options Number of surface smoothing steps 5 4 Triangle quality type yl Number of volume smoothing steps fo 4 Apply Lox Dismiss a Enter 0 25 for Ortho weight b Set the Number of volume smoothing steps to 0 c Retain the default settings for the other parameters and click Apply 5 Compute the mesh Mesh gt Compute Mesh gt Volume Mesh M ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 273 Tetra Prism Mesh Generation for an Aorta Compute Mesh Compute 995 Volume Mesh Mesh Type Tetra Mixed X Tetra Mixed Mesh Mesh Method Robust Octree v IV Create Prism Layers F Create Hexa Core Input Select Geometry All ki F Use Existing Mesh Parts Select o N sake a Ensure that the Mesh Method is set to Robust Octree b Enable Create Prism Layers c Click Compute The progress will be reported in the message window 6 Examine the mesh Figure 208 Octree Mesh for the Aorta p 275 a Disable the display of surfaces Geometry Surfaces b Select Solid amp Wire Mesh Shells Solid amp Wire ANSYS ICEM CFD 14 5 SAS IP Inc All right
129. gl Apply E Dismiss a Enter FLUID in the Part field b Select 2D Planar in the Type drop down list c Click Apply d Enable Vertices under Blocking ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 3 Hexa Mesh Generation for a 2D Pipe Junction Blocking e vertices e Select Numbers under Vertices Blocking Rue vertices ME Numbers Figure 3 Initial Block p 4 shows the initial block enclosing the geometry You will use the initial block to create the topology of the model I Figure 3 Initial Block The curves are now colored separately instead of by part This allows you to distinguish the indi vidual curve entities from each other which is necessary for some of the blocking operations You can enable or disable the color coding by selecting deselecting Show Composite Geometry e gt curves me snow Composite 2 Split the initial block into sub blocks In this case you will split the initial block using two vertical splits and one horizontal split Blocking gt Split Block gt Split Block ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 4 formation of ANSYS Inc and its subsidiaries and affiliates Step 1 Block the Geometry Split Block TTEN CSS 5 Split Block EEE EERE REPEL EEE Block Select Vis
130. gure 221 Blocking Constrained to CYL3 a j x N j curves 1 J en 4 Z x Note This is necessary to meet the Merge Meshes condition that the nodes on both sides of the merge interface be projected to the perimeter curves 5 Create longitudinal O grid Blocking gt Split Block gt gt OGrid Block Z a Click Q Select block s and then click on the only block b Click the middle mouse button to accept c Click Select face s and then select the faces at the two ends of the block corresponding to surfaces INTERFACE2 and OUTLET d Click the middle mouse button to accept ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 298 formation of ANSYS Inc and its subsidiaries and affiliates Generating the Hexa Mesh in CYL3 Figure 222 Block and Faces selected for Ogrid Split x e Click Apply Set edge parameters for blocking Blocking gt Pre mesh Params Update Sizes 9 Note In Settings gt Meshing Options gt Hexa Meshing menu ensure Multigrid level is set to 0 a Ensure Update All is enabled b Click Apply This will have the effect of setting mesh size based on surface mesh parameters specified earlier Refine edge parameters longitudinally Blocking gt Pre mesh Params 9 gt Edge Params Ta a Click Ss Select edge s and then select edge 25 41 b For the number of Nodes enter 17 AN
131. hat Point is enabled in the Entity box default b Click Select vert s and then select vertex 21 top right corner of the block c Click x Select point s and then select the point POINTS 3 See Figure 141 POINTS 3 POINTS 17 and POINTS 1 Location p 181 Note At any point in time while in selection mode you can toggle to dynamic mode by pressing F9 This may be necessary in order to zoom in to get a closer view of the curves Pressing F9 again will toggle back to selection mode You may also enable and disable the display of geometry or blocking entities while selecting a different type of entity For example you may want to disable curves while selecting points d Click Apply to complete the association The vertex moves immediately to the associated point ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 180 formation of ANSYS Inc and its subsidiaries and affiliates Associate Initial Blocking to a Minor Geometry Figure 141 POINTS 3 POINTS 17 and POINTS 1 Location POINTS 18 POINTS 5 POINTS 6 POINTS 4 x x Similarly associate vertex 19 to point POINTS 17 and vertex 11 to point POINTS 1 Note When selecting a vertex you may choose SN Select by numbers from the Select Blocking Vertex toolbar A window pops up Enter the vertex number Click Done and then click the middle mouse button to accept Simi
132. he Geometry Step 4 Creating Composite Curves Step 5 Projecting Edges to the Curves Step 6 Moving the Vertices Step 7 Creating the O Grid Step 8 Generating the Mesh Step 9 Viewing the Scan Planes Step 10 Verifying and Saving the Mesh Preparation 1 Copy the input geometry file geomet ry tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files SphereCube to the working directory Start ANSYS ICEM CFD and open the geometry geometry tin File gt Geometry gt Open Geometry Note If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Step 1 Creating Parts 1 2 Enable Surfaces under Geometry in the display control tree Create a new part for the symmetry surface Rue gt parts be create Part a Enter SYMM for Part in the Create Part DEZ Retain the selection of Nx Create Part by Selection and click S Select entities The Select geometry toolbar will appear X Disable Toggle selection of points x Toggle selection of curves and Toggle selection of bodies 8 material region definition to avoid the selection of entities other than surfaces Ensure that Toggle selection of surfaces is ena
133. he geometry Note In the Display Tree you may temporarily disable the display of Points while select ing a Vertex Be sure to re enable before selecting a Point Similarly disable and re enable Vertices while selecting Points c Click x Select Point s and then select the nearest corner point PNTS 6 to that vertex d Click Apply The vertex will immediately move to the selected point e Similarly associate the following Vertices to the Points See Figure 28 Vertex Associations p 43 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 42 formation of ANSYS Inc and its subsidiaries and affiliates Associate and Fit the Blocking to the Geometry Figure 28 Vertex Associations a am S74 I ae ae i mi anes 2 NENTSIS PNTSI4 Make sure you associate the vertices that appear right on top of their respective points 69 gt PNTS 10 60 gt PNTS 13 66 gt PNTS 1 and 75 gt PNTS 4 The vertices will turn red indicating they are fixed to the prescribed point The blocks should now better represent the geometry of the car Figure 29 Blocks Fit to Car p 43 shows the blocking Figure 29 Blocks Fit to Car AESZS pss E A 7 poas lt Se On eee a pie i 7 i siS ATES 10 TST l _ ee ENTLY j n i Disable the display of Points and Internal Edges Geometry Poi
134. he program File gt Exit ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 320 formation of ANSYS Inc and its subsidiaries and affiliates
135. he rear windshield backlight angle is changed and the windshield is moved slightly rearward Figure 46 Modified Geometry Load the replay file that was saved earlier File gt Replay Scripts gt Load script file Note ANSYS Workbench users All files associated with your project are saved together in a folder with the same name as your Workbench project file If you initiated a second ICEM CFD comonent in your Workbench project you will have to manually search for your replay file In the Replay control window click to highlight the command on line number 1 Click Do all If the Always update option is enabled you can see each step Disabling that option will be faster without display delays This is the real power of replay Note The blocking file is parametric and you can load the saved blocking file from the other configuration and update it to get a similar result Enable Pre Mesh and recompute This mesh will be generated using exactly the same parameters as earlier so the differences in solutions may be attributed to the changes in the geometry rather than to any dissimilarity in the grids ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 59 Hexa Mesh Generation for a 2D Car 11 Figure 47 Final Mesh on Modified Geometry LIH ul HMI re i VANE mn LAU A CE LS Hic
136. his tutorial you will generate a mesh for a two dimensional pipe junction comprising two inlets and one outlet After generating an initial mesh you will check the quality of the mesh and refine it for a Navier Stokes solution Figure 1 2D Pipe Geometry This tutorial demonstrates how to do the following Block the geometry Associate entities to the geometry e Move vertices onto the geometry Apply mesh parameters Generate the initial mesh Adjust the edge distribution and refine the mesh e Match the edges e Verify and save the mesh Preparation Blocking Strategy ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Hexa Mesh Generation for a 2D Pipe Junction Step 1 Block the Geometry Step 2 Associate Entities to the Geometry Step 3 Move the Vertices Step 4 Apply Mesh Parameters Step 5 Generate the Initial Mesh Step 6 Adjust the Edge Distribution and Refine the Mesh Step 7 Match the Edges Step 8 Verify and Save the Mesh and Blocking Preparation 1 Copy the input geometry file geometry tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files 2DPipeJunct to the working directory 2 Start ANSYS ICEM CFD and open the geometry geometry tin File gt Geometry gt Open Geometry Note If you want ANSYS ICEM CFD to behave e
137. i lale Refinement 18 Ignore Wall Thickness al Apply Lox Dismiss a Enter 2 for Max element b Select Enabled for Curvature Proximity Based Refinement and enter 0 5 for Min size limit c Set Refinement to 18 d Click Apply Specify the parts for prism creation Mesh gt Part Mesh Setup a Part Mesh Setup F Show tine params using soale factor Apply infistion parameter to ouves F Remove inflation parameters trom cuves a Enable prism for AORTA_WALL b Retain the default settings for other parameters c Click Apply and then Dismiss The prism height is set to zero which allows it to float The prisms will have a variable thickness calculated to reduce the volume change between the last prism and the adjacent tetra 272 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Generating the Octree Mesh 4 Modify the global prism settings Mesh gt Global Mesh Setup Kol gt Prism Meshing Parameters Global Mesh Setup P Global Mesh Parameters a BS AS Global Prism Settings Growth law exponential xi Initial height jo Height ratio f2 Number of layers 3 s Total height jo Compute params Fix marching direction Min prism quality jor t lt S SC Ortho weight bs Filetratio 010 Max prism angle haoo ooo Max hei
138. i 6 nuay a UA HE e FRITH H zeder H EREE Save the project file Use a suitable name for example 2D_Car Mod File gt Save Project As Create Output Data for a Solver 1 Save the unstructured mesh Blocking Pre Mesh Convert to Unstruct Mesh Export the mesh to the solver Output gt Select solver Select Fluent V6 from the Output Solver drop down list Click Apply Set the boundary conditions Output gt Boundary conditions fay Expand Edges 5 b Expand INLET c Select Create New and then select velocity inlet from the dialog box d Click Okay e Similarly select pressure outlet exhaust fan outlet vent as a boundary condition for OUTLET f Also select wall as the boundary condition for TOP and GROUND g Click Accept to set the boundary conditions Write the input file for ANSYS FLUENT 60 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Create Output Data for a Solver Output gt Write input my The Open dialog box appears a Choose the UNS file created earlier for example 2D_Car_mod b Click Open to open your UNS file The Fluent V6 window will appear c Select 2D for Grid dimension d Enter an appropriate name for the Output file for example 2D_Car_mod e Click Done You can use this MESH file in ANSYS FLUENT to set up and solve AN
139. ial in formation of ANSYS Inc and its subsidiaries and affiliates Step 1 Creating a Material Point Figure 106 Elbow Part With Material Points ELBOW 1 1 3 Click Dismiss to close the Create Body DEZ 4 Save the geometry file elbow new tin before proceeding with the rest of the tutorial File gt Geometry gt Save Geometry As 5 Set up mesh sizes Mesh gt Part Mesh Setup a Part Mesh Setup W Show sxe params using scale Lactor I Apol inflation parameters to ouves I Remove inflation parameters hom curves a Click the max size header The MAX SIZE dialog will appear i Enter 5 for max size ii Click Accept b Similarly set height to 1 and height ratio to 1 2 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 141 Hexa Mesh Generation for an Elbow Part c Click Apply and then Dismiss to close the Part Mesh Setup dialog box Note If you enable hexa sizes Geometry Surfaces Hexa Sizes you can see the hexa size icon on each surface The base size indicates the nominal size on each surface the thickness shows the initial height at the wall if set and the number shows the growth ratio at the wall Setting sizes is a quick way to seed the mesh and these hexa size icons are a quick reference to make sure the sizes are set reasonably However precise mesh size di
140. ianthdncd aah wanes 241 Checking the mesh and Cleaning up ani scatayerata diuamineataomrndominniantn umminiitarunyvaiantes 244 Tetra Prism Mesh Generation for a Helicopter ccccccccesssscccecceeseseesnnnececeeecesseeesnaaeeeeeeeeeseesenaaees 247 PreparatlONy ccicvavisce iden avian CREENA tai Guetta tad penetra Niel en pitta ai eek 248 Step 1 Preparing the Geometry vata soth oc sovesutue vad aalhindsoh aa sot tenoew caution sate cacenedan tla talsoned wsldubher suid salpiubguaen fader 248 Step 2 Creatinig a Material POU ciccevguhocssvaanactneare sens anaes eiin ine sant been a a iai ia 250 Step 3 Generating the Octree Mesh 5 cisissossscdsaricassvanrsecgsnbernevonoasnveabsanbasenssuagsceeesannesy entbaaneubavenseecyen 252 Step 4 Generating the Delaunay Mesli sscsevayssssens aasessstvensnnverenorcearacnasgnenee ey dveneaysasansan doen ipaemnandeoden 259 St p 5 Smoothing the MESH svcccd i cece cecascceedceseuese che tedchas cash setuaaddgbavscaeds a iae aea a A ai a ae ea EARE SKa oiea 262 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Tutorials Step Gs Saving the Projectar surae waaay A E ET EE E AE REE ERRE E EE ERa 263 Tetra Prism Mesh Generation for an Aorta eeeeeseeeessssressseressserressstressssreesssrtessssreesssreessssreessseres 265 Preparati rarrrrierisrir iti di ear is k EEKE OEE EREE A
141. iaries and affiliates Generating the O Grid Blocking gt Split Block gt Ogrid Block Z Click Q Select block s and then select all the Blocks of both the FLUID and SOLID regions You may use 60 Select all appropriate visible objects since the O grid will be added in the entire pipe as shown in Figure 93 Blocks and Faces selected for O grid p 127 Figure 93 Blocks and Faces selected for O grid Similarly click Select face s and then select only the two INLET faces and two OUTLET faces as shown Press the middle mouse button to accept Click Apply to create the O grid Save the updated blocking before continuing on in this tutorial File gt Save Project ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 127 Hexa Mesh Generation for a Pipe with Embedded Blade Figure 94 Completed Blocking cae lt hr DT he be ii yi AAAA pss AE L eS OE AE Swe Note The procedures described here make a parametric blocking file in which the vertices and edges are associated with geometric entities This means that you can modify the geometry keeping the same entity names and then reload the saved blocking file to quickly generate a similar result Defining Surface Parameters for the Mesh In this step the user will define node distributio
142. iates Step 8 Creating an O Grid in the Blocking Split Block Split Block Big OOS Gas Ogrid Block Select Block s gs amp Select Facefs Ss Q Select Edgefs AN amp Select Verts amp DN Clear Selected I Around block s Offset fi Absolute 2 Apply E Dismiss a Click R Select block s and then Select all appropriate visible objects from the selection tool bar Alternatively enter v for all visible blocks or drag a box to select all blocks Note The option a indicating all is not available for blocking to avoid selection of VORFN blocks which are not visible but are still in the model b Click Select face s and select the faces representing the planar geometry INL SYM OUT See Figure 60 Blocks and Faces Selected for O Grid Creation p 82 Click the middle mouse button to accept the selection ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 81 Hexa Mesh Generation for a 3D Pipe Junction Figure 60 Blocks and Faces Selected for O Grid Creation You can also select the faces using any of the following Select Toggle select diagonal corner vertices in the Select blocking face toolbar that appears or type Shi ft D on the keyboard This will allow you to select two diagonally opposite corners that make up the face 2 gt
143. ible C Selected Edge 1119 1 a ee r Copy distribution from nearest parallel edge Project vertices Split Method Split Method Screen select 9 z sonb 0K _ Dismiss a Create the vertical splits i Ensure that Curves is enabled under Geometry Geometry me curves ii Retain the selection of Screen select in the Split Method drop down list Note In this case the split may be done by approximation because only the topology of the T shape is essential the exact proportion is not iii Click Select edge s and select the edge defined by vertices 11 and 19 or by vertices 13 and 21 iv Position the new edge as shown in Figure 4 Initial Vertical Split p 6 and click the middle mouse button to accept the position ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Hexa Mesh Generation for a 2D Pipe Junction Figure 4 Initial Vertical Split The edge 33 34 is cyan colored indicating that it is an internal edge v Similarly select the edge defined by vertices 33 and 19 or vertices 34 and 21 Position the new edge see Figure 5 Block After the Vertical Splits p 6 and click the middle mouse button to accept the position Figure 5 Block After the Vertical Splits ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidentia
144. idential in 94 formation of ANSYS Inc and its subsidiaries and affiliates Step 4 Creating Composite Curves Step 3 Blocking the Geometry The blocking strategy for the sphere cube geometry involves creating an O Grid around the cube and then fitting the inside of the O Grid to the cube using the prescribed points of the model In this step you will create the initial block yasi Blocking gt Create Block gZ gt Initialize Blocks g 1 Ensure that Part is set to the correct material FLUID 2 Retain the selection of 3D Bounding Box in the Type drop down list You need not select entities when creating a bounding box around the entire geometry 3 Click Apply Figure 68 Initial Blocking p 95 Figure 68 Initial Blocking Step 4 Creating Composite Curves Even though curves can be automatically grouped while associating edges to curves sometimes it beneficial to group them first One such benefit is the ability to group all curves that tangentially meet smooth transition at the ends of two adjacent curves In this step you will group all the tangential curves Blocking gt Associate gt Group Curve ad ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 95 Hexa Mesh Generation for a Sphere Cube Geometry oc Blocking Associations Edit Associations a GOTT KDX Group Ungr
145. idiaries and affiliates Step 6 Generate the Pre Mesh Figure 125 Skewed Cells Below 0 6 in the Pre Mesh 1 1 1 1 Oa cece Ob A E E 1 1 1 oi 02 03 These cells can be corrected using the O Grid tool Right click in the histogram window and select Done Disable Pre Mesh Blocking Pre Mesh Enable SOLID Parts SOLID Note These elements are skewed because a mapped block is being fit to a curved shape At the mesh corners projection to the curved shape opens up the element s internal angle to approach 180 degrees The finer the mesh the closer the angle to 180 degrees and the worse the quality of the element The O Grid tool re configures the blocking topology by inserting blocks aligned with the wall and moving this H Grid corner inward to avoid the projection issue The O Grid tool is very robust and can be used to improve the quality on simple models like this or form quality boundary layers for much more complex models It is also ideal for better capturing the physics of the boundary layer profile ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 159 Hexa Mesh Generation for an Elbow Part viscous wall At other times it is advantageous to layer elements normal to the curved wall Step 7 Creating the Second O Grid In this step you will create a second O Grid to improv
146. igure 239 Vertices for Alignment Inline p 317 numbers 184 and 185 as shown Figure 239 Vertices for Alignment Inline X A s ke N 3 4 FLUID Reference To Be Moved c For Vertices click Select vert s d Select the vertex in between number 190 the two reference vertices as shown in Figure 239 Vertices for Alignment Inline p 317 e Click the middle mouse button to accept f Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 317 Multizone Mesh in HVAC Square to circle Transistion Duct The middle vertex snaps into alignment with the endpoints Figure 240 Vertices after Alignment a RTTMITN g Repeat for the three other sides shown in Figure 239 Vertices for Alignment Inline p 317 Reference Direction 184 and 186 Move Vertex 192 Reference Direction 186 and 187 Move Vertex 194 Reference Direction 187 and 185 Move Vertex 195 h Repeat for three other transition regions around the duct 5 Recheck the Pre Mesh Quality Use the default settings Figure 241 After Aligning Vertices Fi Now there are no elements with Quality Metric less than 0 55 and the lowest quality elements are in the circular part of the duct 6 Convert the irregular tetra mesh in the center of the duct to hexa core ANSYS ICEM CFD 14 5 SAS IP Inc Al
147. iliates 251 Tetra Prism Mesh Generation for a Helicopter 5 Click Apply so that FLUID appears under Parts in the display control tree Step 3 Generating the Octree Mesh 1 Assign the mesh sizes Mesh gt Global Mesh Setup Ka gt Global Mesh Size B Global Mesh Setup a Global Mesh Parameters PN BCVHB Global Element Scale Factor Scale factor fi l Display Global Element Seed Size Max element 2048 l Display Curvature Proximity Based Refinement Enabled ee EEREN a iT r Apply Dismiss a Retain the value of 1 for Scale factor b Enter 2048 for Max element The value for Max element is chosen to be 2048 because it is a power of two which is important for Octree mesh generation c Click Apply 2 Specify the parts for prism creation Mesh gt Part Mesh Setup a ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 252 formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Generating the Octree Mesh FUSELAGE CADOS FUSELAGE CADOS FUSELAGE CAD10 4j T Show size params unng scale factor I Apply inflation parameters to curves I Remove inflation parameters from curves a Enable prism for the fuselage parts b Ensure that prism height is set to 0 Setting the prism height to zero allows it to float c Retain the default settings for other parameters d Click Apply and then Dismiss Cre
148. ing the O Grid p 84 Figure 62 Edge Selected for Modifying the O Grid edge selected d Ensure that Absolute distance is disabled e Enter 0 5 for Offset f Click Apply in the Modify Ogrid DEZ 4 Update the surface mesh sizes on the blocking Blocking gt Pre Mesh Params 9 Update sizes P a Retain the selections of Update All and Run Check Fix Blocks b Click Apply in the Recalculate Sizes DEZ c Enable Pre Mesh Blocking Pre Mesh d Click Yes in the Mesh dialog box 5 Refine the mesh using edge parameters ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 84 formation of ANSYS Inc and its subsidiaries and affiliates Step 8 Creating an O Grid in the Blocking Blocking gt Pre Mesh Params gt Edge Params Pre Mesh Params Ga Meshing Parameters a GON Edge atta Ct Lenath 3 42584 Nodes 7 4 Mesh law BiGeometric v Spacing 1 b2 CS 0 200034 I Spl Linked Fieverse Ratio fi2 fless Spacing 2 szan 0 876171 7 Sp2Linked Reverse Ratio 2 iz 0 958314 Max Space fo 0 876171 I Spacing Relative Nodes Locked Parameters Locked V Copy Parameters Copy Method To All Parallel Edges x MV Copy absolute Apply Dismiss a Disable Pre Mesh Blocking Pre Mesh b Click Select edge s and select one of the radial edges c Increase Nodes to 7 d Enter 0 2 fo
149. ing up Starting the Project 1 Copy the input geometry file geomet ry tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files PistonValve to the working directory Start ANSYS ICEM CFD and create a new project in your working directory Use an appropriate name for example PistonValve File gt New Project Open the geometry file geometry tin File gt Geometry gt Open Geometry Build Topology Geometry gt Repair Geometry B gt Build Diagnostic Topology A Set the Tolerance to a value of 0 3 Note Note The default build topology tolerance is calculated as 1 1000th of the distance between the min and max coordinates in the model 0 2 in this case However the geometry is poor and there are many gaps greater than 0 2 If you use the default these gaps would be indicated by pairs of yellow single edge unattached curves By increasing this tolerance to 0 3 build diagnostic topology will walk over these gaps A single red curve is placed between the edges of the surfaces indicating topological connectivity between the surfaces The surfaces are not actually repaired As a general rule of thumb set the topology tolerance to smaller than your smallest mesh size Leave all other defaults and click Apply Enable Filter Curves and Filter Points and leave the default angle at 30 degrees Note Filtered curves or points are made dormant if the surfaces or curves on either
150. inherited v mpu Select Existing Mesh x V Load mesh after completion Compute Dismiss a Ensure that Quick Delaunay is selected in the Mesh Method drop down list b Disable Create Prism Layers The Create Prism Layers option can be disabled as the prisms were already generated during the Octree mesh generation c Ensure that Existing Mesh is selected in the Select drop down list d Ensure that Load mesh after completion is enabled e Click Compute The progress will be reported in the message window Examine the mesh using cut planes a Examine the mesh using a cut plane in the Z direction Manipulate the display to obtain the view shown in Figure 212 Cut Plane Z Direction for the Delaunay Mesh p 282 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 281 Tetra Prism Mesh Generation for an Aorta Figure 212 Cut Plane Z Direction for the Delaunay Mesh b Examine the mesh using a cut plane in the X direction Manipulate the display to obtain the view shown in Figure 213 Cut Plane in X Direction for the Delaunay Mesh p 282 Figure 213 Cut Plane in X Direction for the Delaunay Mesh From Figure 212 Cut Plane Z Direction for the Delaunay Mesh p 282 and Figure 213 Cut Plane in X Direction for the Delaunay Mesh p 282 you can see that the mesh transition is now much smoother
151. is tutorial Create an O grid block around the geometry for boundary layer flow modeling These basic steps will be detailed through the next several sections of this tutorial 1 Create the initial block Wk Blocking gt Create Block Z gt Initialize Blocks g Create Block Q Part FLUID pap e Be Create Block Epp ORIG Initialize Blocks Type 2D Planar bd IV Initialize with settings z Apply Dismiss a Inthe Part field enter FLUID b From the Type drop down list choose 2D Planar c Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 34 formation of ANSYS Inc and its subsidiaries and affiliates Create and Split the Blocking to Resemble the Geometry Figure 22 Initial Blocking l ee ee E The curves are now colored separately instead of by part This allows you to distinguish the individual curve entities from each other which is necessary for some of the blocking operations You can enable or disable the color coding by selecting deselecting Show Composite in the Display tree under Geometry gt Curves Geometry e curves EEH show Composite Associate the four edges of the initial block to the four sides of the wind tunnel Blocking gt Associate gt Associate Edge to Curve O Note When using Hexa for 2D boundary line elements are created only if the edges are associated with the b
152. isible 2 Associate the four edges surrounding the INLET surface to the appropriate curve s Blocking gt Associate amp gt Associate Edge to Curve CS a Enable Project vertices b Select the four edges surrounding the INLET part A in Figure 109 Selection of Edges and Curves for Association p 145 and click the middle mouse button to complete the selection ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 144 formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Fitting the Blocking to the Geometry c Select the curve A in Figure 109 Selection of Edges and Curves for Association p 145 and click the middle mouse button to complete the selection Figure 109 Selection of Edges and Curves for Association d Click Apply to associate the edges to the curves Similarly associate the four edges surrounding the OUTLET surface B in Figure 109 Selection of Edges and Curves for Association p 145 to the appropriate curve B in Figure 109 Selection of Edges and Curves for Association p 145 Move the remaining vertices to the nearest active surface CRA Blocking gt Associate gt Snap Project Vertices ae Note With the edges associated to the appropriate curves the other surface associated vertices can be automatically moved onto the geometry to the nearest active surface ANSYS ICEM CFD 14 5 SAS IP Inc All right
153. ive until recording is complete Record after current is enabled by default all commands will be recorded until you select Done The step of loading the geometry is not typically recorded in the replay script Note If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Throughout this and other tutorials Point Names Curve Names Vertex Numbers and other identifying labels are made visible or turned off as necessary to assist in describing the steps of the tutorial Most experienced users prefer to leave these labels disabled to reduce screen clutter ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 33 Hexa Mesh Generation for a 2D Car Create and Split the Blocking to Resemble the Geometry For an external flow model in a wind tunnel the following steps are usually taken when blocking the model to obtain the desired results e Initialize the blocking and then carve a Cartesian set of blocks around the object using the Split Blocks function Move the vertices onto the geometry in order to fit all its features bumpers hood trunk and so on in th
154. k Mode as it improves efficiency See the Selection menu help for more detail Throughout this and other tutorials Point Names Curve Names Vertex Numbers and other identifying labels are made visible or turned off as necessary to assist in describing the steps of the tutorial Most experienced users prefer to leave these labels disabled to reduce screen clutter Creating Parts in the Mesh Editor Initially all surfaces curves and points of the geometry are in the generic part GEOM The different geometries must be assigned to appropriate parts for further processing 1 In the Display tree enable the display of Points and Surfaces and enable Show Point Names LMB Points Points Show Point Names 2 Create curves for the leading and trailing edge of the blade Geometry gt Create Modify Curve X gt From Points p a Check that the Part name is GEOM ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 110 formation of ANSYS Inc and its subsidiaries and affiliates Creating Parts in the Mesh Editor b Click amp Select location s and then select the two points at the leading edge of the blade GEOM 9 and GEOM 11 c Click Apply or the middle mouse button to accept the new geometry d Similarly create a new curve at the trailing edge of the blade using points GEOM 8 and GEOM 10 Figure 80 Curves for Leading and Trailing edges _ GEOM9 on a B
155. l Edge for Selection b Increase Nodes to 7 in the Pre Mesh Params DEZ c Select Geometric2 from the Mesh law drop down list d Enter 1 for Spacing 2 e Enter 1 5 for Ratio 2 This will bunch the elements close to the car f Enable Copy Parameters and ensure Method is set to To All Parallel Edges default g Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 53 Hexa Mesh Generation for a 2D Car 2 3 4 5 This node distribution will be applied throughout the O Grid Click Ss Select edge s and select one of the vertical edges between the car and the ground h i Increase Nodes to 15 j Retain the other default settings k Click Apply Enable Pre Mesh and recompute See Figure 42 Refined O grid Mesh p 54 Figure 42 Refined O grid Mesh PIA Ka N ee Sey Sarees ees eeeeTerere REE EEE EEE EERE HEE EEE EERE REESE AIEEE EEE REE EERE EEE o EEE EEE EEE EEE EE 9 es ahaa nea Sasa Next to avoid large area differences between adjacent cells you will match node distributions along adjoining edges Disable Pre Mesh Set the Index Control values to l 0 9 and J 0 5 Match the edge spacing of a Reference Edge to a connecting Target Edge 54 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS I
156. l defaults and then click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 296 formation of ANSYS Inc and its subsidiaries and affiliates Generating the Hexa Mesh in CYL3 Figure 220 Initial 3D Bounding Block All geometry will be contained in the created block In the Display tree under Blocking enable Vertices enable Vertices gt Numbers Under Geometry enable Curves gt Show Curve Names and disable Surfaces Constrain the blocking to only CYL3 using Edge to Curve associations Blocking gt Associate amp gt Associate Edge to Curve CG a Ensure that Project vertices is enabled Click a Select edge s and then select the four edges surrounding CURVES 4 identified by vertices 37 38 41 and 42 Click the middle mouse button to accept your selection Click amp Select compcurve s and then click on CURVES 4 at the OUTLET end Click the middle mouse button to accept your selection Click Apply The blocking snaps to the interior of the curve and the four edges turn green indicating a valid association Similarly associate the four edges at the other end of the block between vertices 21 22 25 26 to CURVES 3 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 297 Merged Tetra Hexa Mesh in a Hybrid Tube Fi
157. l edges will automatically have the same number of nodes In this case edges 41 42 and 43 44 will have the same number of nodes as 13 34 and 38 21 respect ively ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 22 formation of ANSYS Inc and its subsidiaries and affiliates Step 6 Adjust the Edge Distribution and Refine the Mesh Figure 15 Bunching After Changing the Number of Nodes 44 d Enable Pre Mesh and recompute the mesh Bias the nodes close to the wall boundaries of the large pipe a Select edge 13 41 and enter 0 5 for both Spacing 1 and Spacing 2 Note Spacing 1 refers to the node spacing at the beginning of the edge while Spacing 2 refers to the spacing at the end of the edge The beginning of the edge is shown by the arrow after the edge is selected b Enter 1 2 for both Ratio 1 and Ratio 2 Requested values for spacing and ratio are typed in the first column Actual values are displayed in the second column Note that due to the number of nodes the mesh law and spacing the re quested ratios may not be attained You may increase the number of nodes using the arrows until the ratios are close to the requested value Note The Mesh Law is by default set to BiGeometric This allows the nodes to be biased towards both ends of the edge The expansion rate from the end is a linear progres sion Several other mathematical progression function
158. l in 6 formation of ANSYS Inc and its subsidiaries and affiliates Step 1 Block the Geometry Create the horizontal split using the Relative split method Split Block Q Split Block a OEHOA owe CREM RELOMS SAC One Visible C Selected Edge 1113 1 eo r Copy distribution from nearest parallel edge Project vertices Split Method Split Method Relative Parameter fo 5 apply OK Dismiss i Select Relative in the Split Method drop down list ii Enter 0 5 midpoint of selected edge for Parameter iii Select any one of the vertical edges and click Apply see Figure 6 Block After Three Splits p 8 Figure 6 Block After Three Splits p 8 shows the split block ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 7 Hexa Mesh Generation for a 2D Pipe Junction Figure 6 Block After Three Splits 3 Delete the unnecessary blocks The next step in this top down approach is to remove delete the blocks that are not required Blocking gt Delete Blocks K a Ensure that Delete permanently is disabled b Click Q Select block s and select the blocks shown in Figure 7 Blocks to be Deleted p 9 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 8 formation of ANSYS Inc and its subsidiaries and affiliates
159. l rights reserved Contains proprietary and confidential in 318 formation of ANSYS Inc and its subsidiaries and affiliates Checking the Mesh Saving and Exiting Blocking gt Edit Block Ad gt Convert Block Type r a In the Type drop down list select 3D Free Block Mesh Type b In the Mesh Type drop down list select Hexa Core c Click Q Select block s d Select block 42 in the middle of the duct where the transition from square to circle occurs Tip If you find it difficult to select the internal block you could adjust the index control set O3 to 0 0 in this case or click N Select by numbers enter the block number 42 in this case in the dialog box and then click Done e Click middle mouse button to accept f Click Apply In the Display tree right click on Pre Mesh and then select Recompute Re examine the internal mesh structure as was done earlier ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 319 Multizone Mesh in HVAC Square to circle Transistion Duct Figure 242 Final Mesh after Conversion to Hexa Core 9 Generate an unstructured mesh output file for a Solver Pre Mesh Convert to Unstruct Mesh This will create and load the hex uns file which can be exported in a wide variety of solver formats 10 Close the project File gt Close Project 11 Exit t
160. l rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 139 Hexa Mesh Generation for an Elbow Part Sphere Cube tutorial for similar instructions and Figure 106 Elbow Part With Material Points p 141 Note If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Step 1 Creating a Material Point Geometry gt Create Body F gt Material Point 1 2 9 yalti Create the FLUID material point within the volume a Enter FLUID for Part Click 3 Select location s and select two locations on opposite sides of the elbow such that the midpoint lies within the ELBOW_1_1 part but outside the CYL part Figure 106 Elbow Part With Material Points p 141 Click the middle mouse button to accept the selection of the points Click Apply so that FLUID appears under Parts in the display control tree Rotate the model to confirm that the new material point is appropriate Similarly create the SOLID material point inside the cylinder You can do this by selecting 2 locations on the edge of the cylinder 140 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confident
161. lade Material Fitting the blocking to the Blade geometry Generating the O grid Defining and Refining the Mesh using Surface Parameters and Edge Parameters Checking mesh quality for determinants and angle e Saving before Quitting Starting the Project Creating Parts in the Mesh Editor Initial Blocking and Associations ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 109 Hexa Mesh Generation for a Pipe with Embedded Blade Splitting and Collapsing Blocks around the Blade Fit the Blocking to the Blade geometry Generating the O Grid Defining Surface Parameters for the Mesh Defining Edge Parameters to Adjust the Mesh Checking and Improving Mesh Quality Saving Starting the Project 1 Copy the input geometry file geomet ry tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files PipeBlade to the working directory 2 Start ANSYS ICEM CFD and create a new project in your working directory Use an appropriate name for example Pipe Blade File gt New Project 3 Open the geometry file geometry tin File gt Geometry gt Open Geometry Note e If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pic
162. larly when selecting a point you may follow a similar procedure starting with Select by name from the Select geometry toolbar Associate vertex 13 to curve CURVE 1 Associating the vertex to the curve constrains its movement to the curve The precise position will be set in the next steps a Inthe Blocking Associations DEZ select Curve in the Entity box b Click s Select vert s and then select vertex 13 c Click the middle mouse button to accept ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 181 Bottom Up Hexa Mesh Strategy for a Grid Fin Click amp Select compcurve s and then select the curve CURVES 1 between points POINTS 1 and POINTS 3 e Click the middle mouse button to accept f Click Apply to complete the association The vertex does not move to the curve immediately 5 Position vertex 13 in the middle of the curve a Blocking gt Move Vertex gt Move Vertex rad Move Yertices Move Vertices Move Vertex Method Single v Vertex R Movement Constraints I Fixx T Fiy P Fisz I Fix direction oo apes Fe I Move dependent faa Apply Dismiss i Click R Select vert s ii Click and drag vertex 13 to a point near the middle of the curve iii Click the middle mouse button to accept 9 b Blocking gt Move Vertex
163. lick the middle mouse button to accept the selection Figure 72 Blocks and Faces Selected for O Grid Creation 6 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 99 Hexa Mesh Generation for a Sohere Cube Geometry 2 The block will also be selected When you select the face both blocks on either side get selected The VORFN block beneath the face is not active so a flat icon is shown instead of the block under neath Click Apply in the Ogrid Block DEZ Figure 73 O Grid Created p 100 Figure 73 O Grid Created Fit the O Grid using prescribed points You will use the central block of the O Grid to represent the cube a Enable Points Geometry Points Enable Vertices Blocking Vertices Associate the vertices to the points mn Blocking gt Associate amp gt Associate Vertex eo Ensure that Point is selected for Entity in the Blocking Associations DEZ ii Click R Select vert s and select a corner vertex of the central block iii Click x3 Select point s and select the corner point closest to the selected vertex on the cube geometry iv Click Apply 100 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 7 Creating the O Grid The
164. ll rights reserved Contains proprietary and confidential in 224 formation of ANSYS Inc and its subsidiaries and affiliates Generate the Tetra Prism Mesh Figure 175 Dialog Box for Part Mesh Setup gt Part Mesh Setup hah mo mn ojo ololcloloic SPOS OT O o o ol o i t I Show see parame using scale factor I Apply inflation parameters to curves I Remove inflation paremeters fom curves Ape Distress Note All sizes on all parts could have been set in this dialog box Most experienced users prefer this for efficiency When set using the Part Mesh Setup dialog box sizes apply to all entity types curves and surfaces within each part 7 Save your project before generating the mesh This will also save changes to geometry tetin file in cluding the mesh parameters setup in this sequence File gt Save Project Generate the Tetra Prism Mesh The initial tetra prism mesh is generated and examined using a cut plane 1 Create the mesh Mesh gt Compute Mesh gt Volume Mesh M a For Mesh Type select Tetra Mixed from the drop down list b For Mesh Method select Robust Octree from the drop down list c Enable Create Prism Layers d Leave all other default values ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 225 Tetra Prism Mesh in a Fin Configu
165. lo curves I Remove inilation psremeters fiom curves ssh c Click Apply and then Dismiss Note Mesh sizes on curves and surfaces may also be setup using Surface Mesh Setup 6 and Curve Mesh Setup a but the Part Mesh Setup dialog box is typically more effi cient when setting multiple parts Save your work File gt Save project Meshing parameters are saved with the geometry file Generating the Tetra Mesh in CYL1 A tetrahedral mesh is generated in the CYL7 region and then saved Later this mesh data file will be opened to complete the merge to another mesh 1 Create a Material point ted atPi Geometry gt Create Body G gt Material Point a Change the Part name to LIVE1 b Click 3 Select location s and then click on two opposite corners of CYL1 Note You may find it useful to disable CYL2 and CYL3 in the display tree while making this selection c Click the middle mouse button to accept the selection ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 291 Merged Tetra Hexa Mesh in a Hybrid Tube d Click Apply to create the Material point Rotate the model to ensure that LIVE1 lies inside the CYL1 section Figure 215 Material Point LIVE1 Created 2 Create mesh in the LIVE1 part Mesh gt Compute Mesh gt Volume Mesh amp a b
166. logy is best seen in a side view View gt Left You can also select the X axis in the display triad in the lower right hand corner to reorient the model as it appears in Figure 51 Geometry Showing Split Locations p 70 c Create a vertical split i Click Select edge s and select one of the horizontal edges ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 69 Hexa Mesh Generation for a 3D Pipe Junction ii Position the new edge near the front end of the small cylinder Figure 51 Geometry Showing Split Locations p 70 and click the middle mouse button to accept the new position d Create a horizontal split i Click Select edge s and select one of the vertical edges ii Position the new edge near the top of the large cylinder Figure 51 Geometry Showing Split Locations p 70 and click the middle mouse button to accept the new position Figure 51 Geometry Showing Split Locations p 70 shows the split block Figure 51 Geometry Showing Split Locations FLUID 3 Delete the unnecessary upper block Blocking gt Delete Block 2 a Click Q Select block s and select the block to be deleted as shown in Figure 52 Block to be Deleted p 71 b Ensure that Delete permanently is disabled c Click the middle mouse button and then Apply in the Delete Block DEZ
167. ly the two surfaces belonging to the solid blade in the middle of the cylinder should be as signed to a part named BLADE Refer to Figure 81 Part Assignments p 113 for the Surface part assignments 112 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Creating Parts in the Mesh Editor Figure 81 Part Assignments For this tutorial leave the curves and points assigned to the initial part GEOM Create fluid and solid Material Points for the interiors of the cylinder and blade respectively The material point that will be created will help us to keep the FLUID region separate from the SOLID region This is not strictly necessary since blocks can simply be created in the FLUID part rather than creating a material point Geometry gt Create Body GB a Enter FLUID in the Part field in the Create Body DEZ yarari b Ensure Material Point is enabled c With the left mouse button select two locations on the opposite sides of the cylinder Click the middle mouse button to accept d Click Apply Note The FLUID material point should not be within the BLADE locations Rotate the model to confirm that FLUID is in an appropriate location e Similarly create a part named SOLID using two locations on the blade surfaces so that the midpoint will be inside the blade ANSYS ICEM CFD 14 5
168. mal Edit Mesh gt Merge Nodes 4 gt Merge Meshes a For Method choose Merge volume meshes b For Merge surface mesh parts click Select part s c In the Select part dialog box choose INTERFACE2 and then click Accept d Click Apply Figure 225 Meshes merged at INTERFACE2 Surface zi A Al Ye B y way Before Merge p7 4 B we 7 g ARRAS AA Pi a 7 7 wf View the pyramids at INTERFACE2 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 301 Merged Tetra Hexa Mesh in a Hybrid Tube a Enable the display of all Parts b Disable the display of Shells c Enable the display of Volumes and then selectively enable and disable the Hexahedra Tetrahedra and Pyramid elements Figure 226 Pyramids at INTERFACE2 5 Reestablish a normal view of all parts and geometries 6 Save the project File gt Save Project Cleaning up and Saving the Project 1 Smooth the Hybrid Mesh Edit mesh gt Smooth Mesh Globally ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 302 formation of ANSYS Inc and its subsidiaries and affiliates Cleaning up and Saving the Project Figure 227 Quality Histogram prior to Smoothing 0 l l l l l I l l l 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 a For Smoothing iterations enter a value of 12 b
169. mesh It will only reduce the number of blocks ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 214 formation of ANSYS Inc and its subsidiaries and affiliates Save the Mesh 1 Save the Mesh pa A A OC ALLAN KCL XS Save the blocking Save the multiblock mesh Figure 169 Complete Blocking after Reducing the Number of Blocks Fa ad ase aa se VY WW PO ra 1 i il gt a Woh Ong r a yO AA T m T File gt Blocking gt Save Blocking As Choose an appropriate filename File gt Blocking gt Save Multiblock Mesh When the Multiblock dialog box appears select the domain type Volume ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 215 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 216 formation of ANSYS Inc and its subsidiaries and affiliates Tetra Prism Mesh in a Fin Configuration In this tutorial example you will generate and smooth a combined tet prism mesh for the volume region surrounding a general fin configuration as well as for the surface of the fin Using a mesh density region allows finer mesh control around the leading and trailing edges of the fin After initial mesh generation Laplace smoothing
170. nc and its subsidiaries and affiliates Refine the Mesh using Edge Parameters Blocking gt Pre Mesh Params gt Match Edges I a Enable Link spacing b Select the Reference Edge as shown in Figure 43 Edges for Matching Parameters p 55 Figure 43 Edges for Matching Parameters Target Edge Reference Edge c Select the Target Edge as shown and then click the middle mouse button to accept d Click Apply to set the edge parameters for the target edge Spacing 2 on the Target Edge is now linked to the end spacing of the reference edge linked 98 42 Changes to the reference edge distribution will automatically affect the edge distribution for this target edge 6 Copy the Edge Spacing to Parallel edges Blocking gt Pre Mesh Params gt Edge Params e a Select the earlier Target edge b Ensure that Copy Parameters is enabled c Select To Visible Parallel Edges from the Method drop down list Copy distribution To All Parallel Edges could include adjusting the distribution at the ceiling of the tunnel As the index control is set to specific value you can limit the copy To Visible Parallel Edges so that only the edges near the car are affected and not the ceiling of the tunnel which is not visible ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 55 Hexa Mesh Generation for a 2D Car d Click Ap
171. nding Box in the Type drop down list You need not select entities when creating a bounding box around the entire geometry c Click Apply 2 Ensure Points are displayed including Show Point Names ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 114 formation of ANSYS Inc and its subsidiaries and affiliates Initial Blocking and Associations In the Display tree enable the display of Vertices and enable vertex Numbers Blocking Vertices Blocking Vertices Numbers Associate the vertices to points on the geometry Blocking gt Associate amp gt Associate Vertex oe a Ensure that Point is selected under Entity b Click Select vert s and then select Vertex 42 upper right corner at the OUTLET end c Click x Select point s and then select Point GEOM 7 nearest to Vertex 42 d Click Apply to create the association as shown in Figure 82 First Vertex to Point Association p 115 Figure 82 First Vertex to Point Association GEOH 4 AN Before Association After Association e Similarly associate the other vertices and points around both INLET and OUTLET When finished your blocking should look like Figure 83 Vertex to Point Associations for the Pipe p 116 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 115 Hexa M
172. neration for an Elbow Part eee ee eesseeccessneeeeeesseeeceesneeeeessaeeecesssaeeeeeesaaeeesesaeeeeeeees 137 Prepatation iirin Terrei aar e EE veecdauea saeebaspobebacvaeaediasiubucausasugeaisy deed auvaadedeasgebudenvaas reac peeebedvuteaaa peeves 138 Step 1 Creating a Material POINT ces ccv csccsedseces scconadsies a Sev E A A Toedd tesdecvdiedss 140 Step 2 BIGCKING the GOOMIGEEY x siscsanaysvvnssiacastincda eae auic dasiendeausvinwl lea taney edule E a E sant E a a 142 Step 3 Fitting the Blocking to the Geometry eee eeeescesersceeessenceeeesseceeseeseeseesesseneeesesseeeeserseeeeseses 144 Step 4 Creating the First O Grid isiansssisvavsierygredraravennes Gucaa wes A a AREE EET E E a A E 148 Step 5 Adjust the O Grid Edge Length to Improve Quality ssssssssssssssesssssesssssressseressssreessssressssreesssee 152 Step 6 Generate the Pre Mesh csscccccccccsseeessneceececceseessnnneeececeesseessneeeeeececeseeessaaeeeeeceeseeeesaaeeeeeess 158 Step 7 Creating the Second O Grid sseessessessssseesseseesssseessssseesssetesssereesssstessssreesssseesssetesssseesssseesssseee 160 Step 8 Generating the M shiiiis micrreriin ira e a nian Oven R A E aE RRE tates 163 Step 9 Saving the Project aoia a aA a E a a a o A a e E E A eai 170 Bottom Up Hexa Mesh Strategy for a Grid Fin eee ee eeeeeecessneeeeeesnneeeeessaeeecesssaeeecessaaeeeeeseaeeeseneas 175 PreparatiON ireeineie inso e aE E E E E E AEE TE EEE
173. ng Blocks around the Blade Splitting and Collapsing Blocks around the Blade In this tutorial the Blade is regarded as a Solid region while the region surrounding the Blade is regarded as a Fluid You will generate a Hexahedral Mesh for both regions but first the Blocking must be Split and then Collapsed around the Blade creating a degenerate Hexahedral mesh in the Blade region Note Before employing the Collapse function for your own applications confirm that the solver accepts degenerated hexas for a structured solver or penta_6 elements prism for an un structured solver The steps instruct the user to split the block in the k direction z direction and i direction x direction around the blade thus creating further blocking topology for the blade For better precision the Prescribed point method is chosen for splitting the blocks in the k direction while the i direction splits will be made by visual judgment 1 In the Display tree disable display of Vertices under Blocking and Surfaces under Geometry Enable the display of Points Click View gt Top and then click BI Fit Window Create z direction splits using Prescribed points Blocking gt Split Block gt Split Block S a Change the Split method to Prescribed point using the drop down list b Click Select edge s and then select one of the vertical z direction edges c Click Select point s and then select Point GEOM 9 bott
174. not have the sizes set ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 8 Generating the Mesh Blocking gt Pre Mesh Params Update Sizes Ensure Update All is selected and click Apply Figure 130 Pre Mesh for the Elbow p 163 Figure 130 Pre Mesh for the Elbow Step 8 Generating the Mesh 1 Adjust the boundary layers by setting the edge parameters Blocking gt Pre Mesh Params amp gt Edge Params i ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 163 Hexa Mesh Generation for an Elbow Part Pre Mesh Params 9 Meshing Parameters a Led oes GO I I Edge 25 127 1 wo Length 16 6982 Nodes f 6 Mesh law BiGeometric x Spacing 1 bs st lt i SCS S 1 00281 F Spl Linked Soicc Beverse Ratio 1 hz 1 11796 Spacing 2 Boo f2 F Sp2 Linked Sci Feverse Ratio 2 eet fi Max Space fs i1211 l Spacing Relative Nodes Locked Parameters Locked MV Copy Parameters Copy Method T o All Parallel Edges yi z apply OK _ Dismiss a Select one of the radial edges as shown in Figure 131 Radial Edge Selected p 164 Figure 131 Radial Edge Selected selected edge b Enter 16 for Nodes c Enter 0 05 for S
175. ns Resolve Zero Thickness Walls Define Periodicity Generate the Mesh Check the Mesh Quality Reduce the Blocks in a Multiblock Mesh Save the Mesh ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 176 formation of ANSYS Inc and its subsidiaries and affiliates Initiate 2D Blocking Preparation 1 Copy the input geometry file geomet ry tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files GridFin to the working directory 2 Start ANSYS ICEM CFD and create a new project in your working directory Use an appropriate name for example Grid_Fin File gt New Project 3 Open the geometry file geometry tin File gt Geometry gt Open Geometry Note If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Throughout this and other tutorials Point Names Curve Names Vertex Numbers and other identifying labels are made visible or turned off as necessary to assist in describing the steps of the tutorial Most experienced users prefer to leave these labels disabled to reduce screen clutter Initiate 2D Blocking Blocking Strategy In this tutorial we will start by creating a 2D blockin
176. ns for the blocking using surface parameters Surfaces should be turned ON in the Display Tree so they can be selected from the screen Mesh gt Surface Mesh Setup 1 Click B Select surface s and then select all surfaces by box selecting the entire model Alternatively press a with the mouse in the graphic window 2 Enter 0 3 for Maximum Size 0 03 for Height and 1 25 for Height Ratio ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 128 formation of ANSYS Inc and its subsidiaries and affiliates Defining Surface Parameters for the Mesh Surface Mesh Setup Suttace s GEOM 16 E eB ee Maximum size o3 Height 0 03 Height ratio 1 25 Num of layers Tetra width Tetra size ratio Minimum size Nill Max deviation Mesh type NONE x Mesh method NONE x Remesh selected surfaces Blank surfaces with params Apply o Dismiss Click Apply to assign the surface parameters Note Display the surface parameters by E Geometry Surfaces Hexa Sizes In Figure 95 Hexa Mesh size on Surface p 129 the quad in the center of the surface represents the max size its thickness represents the height while the number is the height ratio Figure 95 Hexa Mesh size on Surface Disable the display of Hexa Sizes in the Display tree Select Blocking gt Pre Mesh Params 9 Update Sizes Make sure Update All is toggled on default
177. nts Blocking Edges Internal Edges Associate the edges to the curves ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 43 Hexa Mesh Generation for a 2D Car 8 Blocking gt Associate amp gt Associate Edge to Curve O a Click Select Edge s and then select all the edges that lie on the car body by dragging a se lection box with the left mouse button b Click middle mouse button to accept the selection of edges c Click amp Select compcurve s and then select all curves making up the car body individually or by dragging a selection box d Click middle mouse button to accept the selection of curves Click Apply Enable the display of the Internal Edges Blocking Edges Internal Edges Disable the display of Curves to confirm that all the edges around the car body are associated and colored green Geometry Curves Verify that the correct associations have been set Blocking Edges Show Association This display option adds arrows to the middle of each edge or each vertex pointing to the geometry entity if any that the edge vertex is associated with If the edge vertex is already directly on top of the geometry then the arrow is not visible I Enable the display of Curves The association of edges to curves on the front bumper will resemble Figure 30 Edge to Curve Ass
178. ociate the edges denoted D to CURVE D using Figure 118 Edges Projected to the Cylinder Curves p 152 as a guide View the association between edges and curves Blocking Edges Show association Enable the display of Surfaces in the display tree ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 151 Hexa Mesh Generation for an Elbow Part Figure 118 Edges Projected to the Cylinder Curves or ag Step 5 Adjust the O Grid Edge Length to Improve Quality 1 Disable the elbow part surface ELBOW_1_1 in the display tree Parts De eow 1 1 The association arrows point to the outside surfaces of the elbow part Figure 118 Edges Projected to the Cylinder Curves p 152 If you try to snap project vertices now these vertices will move outward to the elbow part surfaces Hence you must disable the ELBOW_1_1 part in the display tree so that the vertices will not move to that part Snap project the vertices to the cylinder Qo Blocking gt Associate gt Snap Project Vertices ae a Ensure that All Visible is enabled b Click Apply The blocking should look like Figure 119 Vertices Projected to the Cylinder p 153 152 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 5
179. ociation at Front Bumper p 45 44 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Align the Vertices Figure 30 Edge to Curve Association at Front Bumper Align the Vertices In this step you will line up vertices on the Cartesian coordinate system to help improve mesh quality Note Similar to the Split Blocks command Align Vertices acts only upon the displayed blocks Therefore it is important to use the Index Control to isolate those blocks 1 Isolate the blocks using index control The index control panel is at the bottom right hand corner a Click Select corners b Select the two diagonally opposite vertices corners below the car as shown in Figure 31 Select Vertices for Index Control p 46 Note This changes the index control values ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 45 Hexa Mesh Generation for a 2D Car Figure 31 Select Vertices for Index Control Corners to be selected 2 Display the corner Indices for the Vertices Blocking Vertices Indices 3 Select Align Vertices rE Blocking gt Move Vertex gt Align Vertices tiik a Click a Select edge s and then select one vertical J edge to define the index align
180. ocks to Delete c Click the middle mouse button or Apply in the Delete Block DEZ to accept your selection d Ensure that Delete permanently is disabled default and then click Apply The parts are not deleted permanently but are put into the VORFN part a holding place for dormant parts This helps maintain connectivity and allows easy retrieval if necessary Note In a different situation where a solid mesh is needed for example Conjugate Heat Transfer CHT a new part SOLID would be created and then these blocks would be assigned to the new part e Save the blocking File gt Blocking gt Save Blocking As Provide a filename for example 2DCar_base_geometry b1k so that the file can be reloaded at a later time using File gt Blocking gt Open Blocking 6 Manage the Replay control recording Bring the Replay control window to the foreground to see the recording of commands You can manually insert or delete commands directly from the Replay control window or click Edit to open the complete list in your default text editor such as Notepad Remove the command used to save your blocking file Highlight the command and then click Delete One This is the one that starts with ic_hex save_blocking The Undo groupings are added by ANSYS ICEM CFD to assist in replay control While they may be removed by clicking the Clean button this is suggested ONLY if you have stepped through your work flow wi
181. oefficients from the Method drop down list ii Enter 0 5 for Bz iii Click Apply Enable the display of volumes in the display control tree Mesh Volumes Select Solid amp Wire Mesh Volumes Solid amp Wire ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 257 Tetra Prism Mesh Generation for a Helicopter The cut plane appears as shown in Figure 198 Cut Plane in Z Direction for Octree Mesh p 258 Figure 198 Cut Plane in Z Direction for Octree Mesh f Enable Surfaces Geometry Surfaces g Zoom in and examine the effect of the density box on the mesh Figure 199 Zoomed in Cut Plane in Wake Region p 258 Figure 199 Zoomed in Cut Plane in Wake Region h Disable the display of volumes and surfaces Mesh Volumes Geometry Surfaces i Disable Show Cut Plane in the Manage Cut Plane DEZ ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 258 formation of ANSYS Inc and its subsidiaries and affiliates Step 4 Generating the Delaunay Mesh 8 Check the mesh for any errors that may cause problems during the analysis Edit Mesh gt Check Mesh Check Mesh P Check Mesh j w Possible Enor Problems NM Duplicate element V Multiple
182. om of blade geometry d Click Apply to create the split e Similarly create two more splits using points GEOM 8 top of blade geometry and GEOM 12 middle of blade geometry Note Make sure that the span of the Edge that is selected includes the Prescribed Point that will be selected See Figure 86 Z direction Splits p 120 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 119 Hexa Mesh Generation for a Pipe with Embedded Blade Figure 86 Z direction Splits 4 Create x direction splits using Screen select a Change the Split method to Screen select using the drop down list Click Select edge s and then select one of the horizontal x direction edges Click and drag the split along your selected edge until it is aligned over one of the points on the side widest part of the blade geometry Note A single click and drag may be used to position the split Alternatively multiple click and drag operations may be performed as necessary prior to clicking the middle mouse button Click the middle mouse button to accept Similarly create another split aligned over the opposite side of the blade geometry See Figure 87 X direction Splits p 121 120 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc
183. omplete the operation d Deselect Show Point Names Geometry kme points Ee show Point Names 4 Save the blocking file 2 dpipe geometry b1k File gt Blocking gt Save Blocking As The saved blocking file can be reloaded at a later time using the File gt Blocking gt Open Blocking menu item Step 4 Apply Mesh Parameters In this step you will set mesh parameters sizes on the geometry curves in this 2D case This is done at the geometry level and can be done before or after the blocking Mesh gt Curve Mesh Setup a ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Hexa Mesh Generation for a 2D Pipe Junction Curve Mesh Setup G Curve Mesh Parameters Method General x Select Curvefs CURVES 5 CURVES R EERE Maximum size i Number of nodes Height Height ratio Num of layers fo Tetra width 0 la Min size limit 0 I Max deviation 0 Advanced Bunching Bunching law o Spacing 1 Ratio 1 P Spacing 2 Ratio 2 Max space V Curve direction Reverse direction r Remesh attached surfaces Blank curves with params Apply ox Dismiss 1 Click R Select curve s The Select geometry toolbar will appear 2 Click Select all appropriate visible objects or enter v for visible in the display window
184. oundary conditions bey a Set the boundary condition for AORTA_WALL to wall i Click Create new under AORTA_WALL Selection Select a BC type fw tt ts mass flow inlet outflow periodic pressure far field pressure inlet inlet vent intake fan pressure outlet exhaust fan outlet vent solid symmetry velocity inlet ii Select wall from the list of Boundary Conditions in the Selection dialog box iii Click Okay iv Enter the required zone ID b Similarly set the boundary conditions for INLET to velocity inlet and OUTLET to pressure outlet exhaust fan outlet vent c Set the boundary conditions for FLUID to fluid ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 284 formation of ANSYS Inc and its subsidiaries and affiliates Step 5 Saving the Project Family boundary conditions fluid FLUID Zone id jo Create new A Paste Delete Copy Boundary Conditions ADRTA WALL Create new Paste Boundary Conditions Create new Paste Boundary Conditions ia VW velocity inlet OUTLET Create new Paste Boundary Conditions y pressure outlet exhaul Accept Cancel d Click Accept after setting the boundary conditions Note Mixed unknown refers to the dimension of the elements in a part If a part contains all volume elements it clearly belongs in the Volumes branch Similarly parts in the Surfaces branch shoul
185. oundary curves and they are required before boundary conditions may be ap plied It is good practice to associate all perimeter edges with perimeter curves before the edges are split Then when the edges are split all segments will retain the necessary association a For reference enable the display of Vertices by Numbers and Show Curve Names Blocking me Vertices Blocking Rue gt vertices me Numbers Geometry Rue gt curves me show Curve Names I ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 35 Hexa Mesh Generation for a 2D Car b Click Select edge s and then select the edge 11 13 endpoints are vertices 11 and 13 Click the middle mouse button to accept the selection Note At any point in time while in selection mode you can toggle to dynamic mode by pressing F9 This may be necessary in order to zoom in or out or otherwise manip ulate the display Pressing F9 again will toggle back to selection mode c Click amp Select compcurve s and then select the curve INLET 1 that lay on top of the edge Click the middle mouse button to accept Edit Associations BOS Cr KDXL Associate Edge gt Curve Egs nnna U TE Curve s NET 00 C i C C C C S R Project vertices Project to surface intersection Project ends to curve int
186. oup curyes Action Group Curves Ungroup Curves Group C Selected All tangential Part by Part SA d Apply ae Dismiss 1 Retain the selection of Group Curves 2 Select All tangential for Group 3 Click Apply in the Group Ungroup curves DEZ Note This feature needs geometry connectivity If you hadn t run build topology you will be prompted to do so now All four base curves forming the circular perimeter of the hemisphere will be grouped as shown in Figure 69 Grouped Tangential Curves p 97 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 96 formation of ANSYS Inc and its subsidiaries and affiliates Step 5 Projecting Edges to the Curves Figure 69 Grouped Tangential Curves Step 5 Projecting Edges to the Curves Blocking gt Associate amp gt Associate Edge to Curve O 1 Click Ss Select edge s and select the four bottom edges using the left mouse button Click the middle mouse button to accept the selection 2 Click amp Select compcurve s and select the grouped circular curve using the left mouse button Click the middle mouse button to accept the selection 3 Click Apply in the Associate Edge gt Curve DEZ The selected edges will turn green 4 Enable Vertices in the display control tree Blocking Vertices 5 Enable the display of vertex numbers Blocking Vertices Numbers 6 V
187. ow Part In this tutorial you will generate a hexa mesh for a three dimensional elbow intersected internally by a cylinder Figure 105 Elbow Geometry This tutorial demonstrates how to do the following Create the material point e Block the geometry e Split the blocks Fit the computational domain to the geometry Create the first O Grid Create the second O Grid Generate the mesh e Verify and save the mesh Preparation Step 1 Creating a Material Point ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 137 Hexa Mesh Generation for an Elbow Part Step 2 Blocking the Geometry Step 3 Fitting the Blocking to the Geometry Step 4 Creating the First O Grid Step 5 Adjust the O Grid Edge Length to Improve Quality Step 6 Generate the Pre Mesh Step 7 Creating the Second O Grid Step 8 Generating the Mesh Step 9 Saving the Project Preparation 1 Copy the input geometry files Elbow agdb and Elbow tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files ElbowPart to the working directory Note These two files are of the same geometry The agdb file is in the native Workbench format while the tin file is in the native ANSYS ICEM CFD geometry format Assuming you have the Workbench Readers proceed to the next steps in this
188. own methods as is done in other tutorials For example the triangles between the fins could be handled with the option to create Y blocks or by creating an Ogrid and then collapsing the corners However the point of this tutorial is to introduce bottom up blocking concepts that will be helpful on very difficult examples Further since the geometry does not change significantly in the Z direction the 3D blocking is created by extruding an initial 2D blocking This is simpler than building a bottom up 3D blocking you don t need to select as many vertex locations but the concept is the same Also the Grid Fin is part of a rotating machine You will minimize the model size by modelling only a section of the rotating machinery and then implementing symmetry with Periodic nodes The geometry is as shown in Figure 139 Grid Fin Geometry p 176 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 175 Bottom Up Hexa Mesh Strategy for a Grid Fin Figure 139 Grid Fin Geometry This tutorial demonstrates how to do the following Preparation Initiate 2D Blocking Associate Initial Blocking to a Minor Geometry Create an O grid and Place Vertices Rotate and Copy to Resolve Other Geometries Complete the 2D Grid by Vertex Placement Extrude a 2D Planar Grid to Create 3D Blocking Refine the Blocking with Further Splits and Associatio
189. pacing1 d Enable Copy Parameters and ensure that To All Parallel Edges is selected in the Method drop down list ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 164 formation of ANSYS Inc and its subsidiaries and affiliates Step 8 Generating the Mesh e Click Apply You have adjusted the boundary layers for all edges f Recompute the pre mesh Blocking Pre Mesh Figure 132 Pre Mesh After Adjusting the Boundary Layer INLET OUTLET In Figure 132 Pre Mesh After Adjusting the Boundary Layer p 165 initially there is uniformity and then the mesh size suddenly increases after a certain point You will manually adjust edge para meters and use match edges to rectify this This will also result in better quality 2 Adjust the uniformity over the edges Blocking gt Pre Mesh Params amp gt Edge Params i a Select any radial edge as shown in Figure 133 Selected Edge p 166 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 165 Hexa Mesh Generation for an Elbow Part Figure 133 Selected Edge selected edge The arrow points inwards b Set Spacing2 to 0 25 In the Meshing Parameters DEZ c Enable Copy Parameters and select To All Parallel Edges in the Method drop down list This setting is thus copied to all the edges d
190. ply 7 Repeat the Match Edges and Copy Parameters steps for the edge behind the car 8 Enable Pre Mesh and recompute the mesh See Figure 44 Full Mesh prior to Smoothing p 56 Figure 44 Full Mesh prior t to Smoothing a nu gg A 9 Smooth the Mesh Blocking gt Pre Mesh Smooth s a From the Method drop down list choose Orthogonality b Accept all other defaults c Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 56 formation of ANSYS Inc and its subsidiaries and affiliates Save the Replay File and Use it for Design Iteration Figure 45 Final Mesh on Base aise ma a 8 An hi ESE Ay F EETA ANN f AA ws I Sri Be Lo mipi a ER i p E pE E EE SIgusedtsdetiaeesataabeattesaeta ERNES STAZESE Hi Hai ST EN a a a FE EEE EFIAFI AEAEE EET Note For simplicity not all possible edge parameter refinement was done in this tutorial For completeness you may wish to set and match edge parameters above the car geometry before smoothing Save the Replay File and Use it for Design Iteration The replay file can contain all steps for outputting the mesh and can be used in batch mode from the com mand line using icemcfd batch script replay file rpl In this tutorial you will use the Replay file interactively 1 Bring the Replay control window to the foreground 2 Right click on the Replay control window near the t
191. ply Figure 101 Angle Quality Histogram before Smoothing Note An angle greater than 18 degrees is acceptable for most commercial solvers To display cells of a particular determinant or angle value click on a histogram bar Cells within that range will be highlighted allowing closer inspection You will have to change the Pre Mesh display to Wire Frame from Solid amp Wire Run the Pre mesh Smoother Blocking gt Pre mesh Smooth 5 In the Method drop down list select Quality Enter Smoothing iterations 3 Up to quality 0 5 and Criterion Angle Under Advanced Options enable Active Parts only Click Apply to smooth mesh 134 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Checking and Improving Mesh Quality Changes in the minimum angle of the mesh can be seen in the histogram as shown Figure 102 Angle Quality Histogram after Smoothing You can examine the mesh in cross section using the Cut Plane Blockin Pre Mesh Cut Plane g In the Display tree disable the display of Pre Mesh a Using the Method drop down list select Middle Z plane See Figure 103 Mid Z Cut Plane p 135 Figure 103 Mid Z Cut Plane 2 ov Z gt Pm Y x FLUID leno v c Use the scroll wheel to mo
192. prietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 189 Bottom Up Hexa Mesh Strategy for a Grid Fin Figure 147 Vertices and Points selected for First Block Location 1 Location 0 E T Si o zal d Click middle mouse button to accept the selection Note The order of selecting vertices locations is important for the block creation You need to select vertex 11 before 13 and location 0 before 1 This is refered to as a Z pattern Also selecting a combination of vertices and locations it is important to start your Z pattern so that the vertices are selected before the locations See Create Blocks From Vertices Faces in the Help documentation for more info e Click Apply See Figure 147 Vertices and Points selected for First Block p 190 The block is drawn and the new vertices are numbered 99 and 100 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 190 formation of ANSYS Inc and its subsidiaries and affiliates Complete the 2D Grid by Vertex Placement 2 Similarly create the second block a Click Select vert s and then select the vertices 13 21 and 100 in that order b Click middle mouse button to accept the selection c Select the location as shown in Figure 148 Vertices and Points selected for Second Block p 191 Figure 148 Vertices and Points selected for Second Block Loca
193. proprietary and confidential in 242 formation of ANSYS Inc and its subsidiaries and affiliates Generating the Mesh VALVE IV Show size params using scale factor I Apply inflation parameters to curves I Remove inflation parameters from curves Apply Dismiss Click Apply and then Dismiss b Re compute the mesh this time with prisms Mesh gt Compute Mesh c Enable the check box beside Compute Prism Layers d Click Compute When reminded that the Mesh Already Exists click Replace 5 Display the Tetra Prism volume mesh using the same sequence as above ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 243 Tetra Mesh in a Piston Valve Assembly Figure 189 Tetra Prism Volume Mesh around Valve Checking the mesh and Cleaning up In this sequence the mesh will be checked for errors and then improved by a Linear to quadratic transform ation 1 Check the mesh Edit Mesh gt Check Mesh a Accept all defaults b Click Apply c If asked to delete unconnected vertices click Yes ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 244 formation of ANSYS Inc and its subsidiaries and affiliates Checking the mesh and Cleaning up Figure 190 Finished Mesh on the Piston Valve Save the mesh and all other associated proj
194. r Spacing 1 e Enable Copy Parameters and select To All Parallel Edges in the Method drop down list f Enable Copy absolute and click Apply in the Meshing Parameters DEZ g Enable Pre Mesh Blocking Pre Mesh h Click Yes in the Mesh dialog box ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 85 Hexa Mesh Generation for a 3D Pipe Junction i Disable Curves and Surfaces under Geometry and Edges under Blocking in the display control tree The final mesh is shown in Figure 63 The Final Mesh p 86 Figure 63 The Final Mesh Step 9 Verifying and Saving the Mesh 1 Check the mesh quality Blocking gt Pre Mesh Quality Histograms a Select Angle in the Criterion drop down list and click Apply You can see the improved mesh quality in the histogram Figure 64 Histogram of Angle p 86 Figure 64 Histogram of Angle b Select Determinant 2x2x2 in the Criterion drop down list and click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 86 formation of ANSYS Inc and its subsidiaries and affiliates Step 9 Verifying and Saving the Mesh Save the mesh in unstructured format Blocking Rue gt pre Mesh Convert to Unstruct Mesh This saves the uns file as the mesh in the working directory and automatically loads it Sa
195. r selection rectangles for Association to SHELL 6 Check the Face to Surface associations a In the Display tree enable the display of Faces b Under Faces enable Face Projection Blocking me faces De face Projection ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 206 formation of ANSYS Inc and its subsidiaries and affiliates Define Periodicity Figure 163 Faces associated to Surfaces on parts PLATE1 PLATE2 and SHELL Note The faces have same color as the part to which they are associated c Disable the display of Faces 7 In the Index Control window click Reset Note The two faces corresponding to the HUB part remain disassociated Define Periodicity Periodic functionality plays a key role in properly analyzing rotating machinery applications for example Typically the user will model only a section of the rotating machinery as well as implement symmetry in order to minimize the model size By specifying a periodic relationship between the inflow and outflow boundaries flow characteristics at the inflow boundary must be identical to the flow characteristics at the outflow the section specification may be extended to the full model Defining periodicity in ANSYS ICEM CFD requires periodic parameters such as axis location axis orientation and angle to be specified Often these parameters are applied to entities that
196. raphics window ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 254 formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Generating the Octree Mesh 5 Enter 1211 for X Offset The X Offset value is chosen approximately half the length of the aircraft Click Apply The density box is translated half the length of the fuselage Figure 195 Density Box Translated to the Wake Region p 255 You will use this to refine the wake region Figure 195 Density Box Translated to the Wake Region Compute the mesh Mesh gt Compute Mesh gt Volume Mesh H Compute Mesh Q Compute PX EAZA Volume Mesh Mesh Type Tetra Mixed X Tetra Mixed Mesh Mesh Method Robust Octree IV Create Prism Layers F Create Hexa Core Input Select Geometry all yj 7 Use Existing Mesh Parts Select oe Compute Ei Dismiss Ensure that the Mesh Method is set to Robust Octree Enable Create Prism Layers Click Compute ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 255 Tetra Prism Mesh Generation for a Helicopter The progress of meshing will be reported in the message window 6 Examine the mesh Figure 196 Octree Mesh for Helicopter p 256 a Disable the display of surfaces Geometry Surfaces
197. ration e Click Compute Note The default prism parameters Mesh Global Mesh Setup Prism Meshing Params indicate 3 prism layers using the local prism thickness based on the surface triangle size as no initial height is specified 2 View a cut plane at the leading surface of the fin Mesh gt Cut Plane gt Show Cut Plane Mesh Volumes Solid amp Wire Also in the Display tree enable Surfaces and then disable INLET OUTLET BOX and SYMM a For Method select Middle X plane from the drop down list b Use the scroll wheel to move the cut plane Zoom pan and rotate using left middle and right mouse buttons ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 226 formation of ANSYS Inc and its subsidiaries and affiliates Check and Smooth the Tetra Prism Mesh Figure 176 Cut Plane View for Initial Tetra Prism Mesh Note In this cutplane view the sides of the prism layers appear as smooth regular four sided figures The Density regions at the leading and trailing edges of the fin increases resolution with a smaller local maximum size on surface and volume elements within the region Check and Smooth the Tetra Prism Mesh In this sequence automated error checking and smoothing are used to improve the mesh before converting to Hexa core 1 Error checking the mesh Edit Mesh gt Check Mesh Z a Accept the default settings If asked
198. reviously created Click Open b The Mesh Exists dialog box opens Choose Merge Figure 218 CYL1 and CYL2 Meshes Open Note At this point the two mesh files are simply concatenated Merging the meshes to form a conformal mesh is a later step 2 In the Display tree turn OFF all parts except INTERFACE1 and then reorient the model for an end view 3 Make the two meshes conformal Edit Mesh gt Merge Nodes 4 gt Merge Meshes ce a For Method choose Merge volume meshes b For Merge surface mesh parts click Select part s ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 295 Merged Tetra Hexa Mesh in a Hybrid Tube c In the Select part dialog box choose INTERFACE1 and then click Accept d Click Apply Figure 219 Meshes merged at INTERFACE1 Surface AISI RAY aT ENG HANNA RORIS FRERES NAY AI RAY 4 Reestablish a normal view of all parts and geometries 5 Save the project File gt Save Project Generating the Hexa Mesh in CYL3 Blocking is required in the CYL3 region before creating the Hexa mesh The cylindrical shape lends itself very well to the creation of an O grid block scheme 1 In the Display Tree disable Mesh to reduce screen clutter 2 Generate initial blocking Blocking gt Create Block amp gt initialize Blocks g Accept al
199. rials Parts Points Curves Surfaces and their identifying labels may be made visible or turned off as necessary to assist in describing the steps of the tutorial Typically to avoid screen clutter the default settings for visibility are sufficient for most work and such steps are used only to isolate specific parts for specific tasks Setting the Mesh Parameters Mesh parameters for the entire model will be set Parameters for individual parts may be set locally at the time the mesh is generated 1 Set maximum element size globally Mesh gt Global Mesh Setup Kol gt Global Mesh Size B a For the Scale factor enter a value of 1 b For the Max element enter a value of 16 c Click Apply Set mesh sizes on surfaces and curves Mesh gt Part Mesh Setup ro The Part Mesh Setup dialog box appears a For parts CURVES CYL1 CYL2 and CYL3 set the max size value to 4 b For parts INLET INTERFACE1 INTERFACE2 and OUTLET set the max size value to 2 290 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Generating the Tetra Mesh in CYL1 _ loi Z a a a a a a e min A CURVES CYL r 0 CrL2 0 CrL3 a E B E E E 0 0 0 INLET 2 0 0 0 0 INTEAFACET gt INTERFACE m OUTLET Imi 4 V Show size params uting scale factor T Apply inflation peremeters
200. rm the asso ciation has occurred by temporarily disabling the display of Curves f Similarly associate the remaining curves defining the hub CURVES 36 CURVES 28 and CURVES 34 with the edges that lie on top of them Associate all internal edges to their respective curves as much as possible Internal edges are colored blue ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 201 Bottom Up Hexa Mesh Strategy for a Grid Fin Disabling and enabling the display of Curves will allow you to identify where a curve is underlying an edge and to confirm that your associations are completed You may find it useful to change the Index Control for dimension K to 2 3 when associating the edges around the Shell part 10 Also associate all external edges to their respective curves 11 Associate all vertices to their nearest geometry points wherever possible As with Curves and Edges it is useful to disable one type of entity while selecting another 12 Move all the vertices onto the geometry aor Blocking gt Associate gt Snap Project Vertices a a Under Vertex Select retain the selection of All Visible b Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 202 formation of ANSYS Inc and its subsidiaries and affiliates Resolve Zero Thickness
201. roject Preparation 1 Copy the input geometry file helicopter tin from the ANSYS installation directory under v145 icemcfd Samples CFD_Tutorial_Files Helicopter to the working directory 2 Start ANSYS ICEM CFD and open the geometry helicopter tin File gt Geometry gt Open Geometry Note If you want ANSYS ICEM CFD to behave exactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Step 1 Preparing the Geometry In most cases you would put the parts comprising the helicopter fuselage into a single part and then build topology to extract feature curves In this tutorial you will retain each surface in its own part to better illustrate the patch independence Also you will skip the build topology step and instead extract the feature curve from the symmetry plane 1 Enable Surfaces under Geometry in the display control tree Geometry Surfaces 2 Zoom in to the helicopter fuselage and examine the geometry The overlapping surfaces and slivers are shown in Figure 192 Overlapped Surfaces and Slivers p 249 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 248 formation of ANSYS Inc and its subsidiaries and affiliates Step 1 Preparing the Geometr
202. roprietary and confidential in 194 formation of ANSYS Inc and its subsidiaries and affiliates Refine the Blocking with Further Splits and Associations Figure 151 Initial 3D Blocking after Extrusion Refine the Blocking with Further Splits and Associations In this sequence of steps you will further split the blocking delete unused portions and associate the final blocking to the geometry In the Display tree under Geometry enable Points and Curves and disable Surfaces Under Blocking enable Edges and disable Vertices 1 Split the blocks to define the length of the Shell and Hub parts Blocking gt Split Block gt Split Block a From the Split Method drop down list select Prescribed point b Click Select edge s and then select any edge in the z direction c Click x Select point s and then select the point POINTS 16 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 195 Bottom Up Hexa Mesh Strategy for a Grid Fin d Click Apply e Similarly split the block again by selecting any edge in the z direction and point POINTS 8 See Figure 152 Blocks after first z direction splits p 196 with display of Points disabled Figure 152 Blocks after first z direction splits y 4 GA N ALLAH V A Pi a A RLN V NM Ai AYA i EVA A AN A J
203. rs Blocking gt Pre Mesh Params Update Sizes a b Check that Method is Update All Click Apply This will automatically determine the number of nodes on the edges from the mesh sizes set on the curves 48 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Set Mesh Parameters and Generate the Initial Mesh Enable Pre mesh Allow recompute when prompted Blocking Pre Mesh Figure 36 Cartesian Grid before Edge Parameters HRES Er annn nn nn i ERERFEEE EEEE EEEF EHEH SEZEZEEEEEEJ seeeaeeees Hi r eeere IEEE toos Realises te ESTEE ii Ag o J PR peN U Mg Loa H HER ataaguipigigigtizipisteteseeaees FAH ians H en ii et HH e n HREH bieeeere This creates a body fitted blocking that is aligned with indices and J This is known as a Cartesian or H Grid type of blocking Set Edge Parameters Blocking gt Pre Mesh Params amp gt Edge Params Pa a In the Display Tree Disable Pre Mesh and Enable Vertices by Number b Click a Select edge s and then select edge 11 37 along the GROUND part in front of the CAR c Set the number of Nodes to 50 d Click Apply e Click s Select edge s and then select edge 48 38 vertical edge above the front of the car f Set the number of Nodes to 50 g Enter 1 2 for Ratio1 and Ratio2
204. ry entities 1 In the Display tree disable Curves 2 Create parts for the surfaces Parts Create Part For the Part name enter SHROUD D Click x Select entities and then click on the curved surface at the top of the geometry ez See Figure 183 SHROUD PORT and CYL Identified p 236 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 235 Tetra Mesh in a Piston Valve Assembly c Click Apply d Similarly create separate parts for PORTand CYL Note Some parts include multiple surface entities Your colors may differ from what is shown here Figure 183 SHROUD PORT and CYL Identified SHROUD e Create separate parts for SEAT STEM and VALVE See Figure 184 SEAT STEM and VALVE Identi fied p 237 Tip In the Display tree you can disable the display of parts already created making it easier to zoom in to name the remaining parts ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 236 formation of ANSYS Inc and its subsidiaries and affiliates Defining the Parts Figure 184 SEAT STEM and VALVE Identified Note If a surface is missed it may be easily added to the part using partname Add to part 3 Optional Create parts for curves CUR and points PTS The curve point sele
205. s Setting Mesh Parameters Ensure the Min Size is set to 1 Note Curvature Proximity Based Refinement allows ANSYS ICEM CFD to determine local tetrahedral or triangle sizes based on the size of the features in the model Paramet ers set here are used to set a local minimum size limit the number of elements between two geometries or the number of segments used to define a curved edge d Click Apply 2 Specify Volume Mesh parameters Mesh gt Global Mesh Setup gt Volume Meshing Parameters e gt a For Mesh Type select Tetra Mixed from the drop down list b For Mesh Method select Robust Octree from the drop down list c Click Define thin cuts The Thin cuts dialog box opens Note A thin cut region is any region between two parts that may be thinner than the tet rahedral mesh element defined on the parts Defining thin cuts ensures the surface mesh respects the two surfaces rather than have surface mesh elements span the nodes between the surfaces For successful implementation the two parts can never touch and in this case they are separated by a curve in a 3rd part Click Select The Select part dialog box opens Click PORT to select the first part Click STEM to select the second part The Select part dialog box closes returning you to the Thin cuts dialog box iv Click Add The two part names will appear in the Thin cuts window v Click Done to return to the Global Mesh Setup
206. s 293 Merged Tetra Hexa Mesh in a Hybrid Tube e Click Apply The Material point should now be located within the CYL2 region Rotate the model to confirm 2 Rename the Material point to LIVE2 Part LIVE1 Rename Change the name and then click Done 3 Create the mesh in the LIVE2 part Mesh gt Compute Mesh gt Volume Mesh amp a For Mesh Type select Tetra Mixed from the drop down list b For Mesh Method select Robust Octree from the drop down list c For Select Geometry select All from the drop down list d Click Compute to generate the mesh Figure 217 Tetra Mesh in CYL2 Region Created A A f P X INI 7S E S f EA Fi KAA O NY r AN rN f PN Fi j j 4 es os Se XN as eee Ae Fi ad PANA z LL ERRON GERRI sA CORA Apr o se el vr a se ae a oe EIE 4 Save the mesh data File gt Mesh gt Save Mesh As Choose an appropriate name for example Cy12_Tetra_Mesh uns Do not close the mesh data file ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 294 formation of ANSYS Inc and its subsidiaries and affiliates Merging the Tetra Mesh between CYL1 and CYL2 Merging the Tetra Mesh between CYL1 and CYL2 The first two volume meshes are made conformal at their common surface INTERFACE 1 Reopen the first mesh File gt Mesh gt Open mesh a In the Open dialog box choose the mesh file p
207. s laws are available ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 23 Hexa Mesh Generation for a 2D Pipe Junction 10 Enable Copy Parameters and retain the selection of To All Parallel Edges in the Method drop down list This will ensure that the parallel edges 34 42 38 43 and 21 44 have the same spacing Click Apply Select edge 21 38 and change Spacing 1 and Spacing 2 to 0 5 This will concentrate grid points toward the outlet and toward the small pipe Ensure that Copy Parameters is enabled and To All Parallel Edges is selected in the Method drop down list These changes will be reflected in edge 43 44 as well Click Apply Copy the same distribution to the other section of the large pipe a Select To Selected Edges Reversed in the Method drop down list in the Copy group box Click Select edge s and select edges 13 34 and 41 42 Click the middle mouse button to accept Click Apply Refine the nodes along the small pipe Select edge 33 42 and enter 9 for Nodes Enter 1 0 for Spacing 1 and 0 5 for Spacing 2 respectively Ensure that Copy Parameters is enabled and select To All Parallel Edges in the Method drop down list Click Apply Select edge 34 38 enter 9 for Nodes and click Apply Disable and then enable Pre Mesh to recompute the mesh Figure 16 Refined Mesh p
208. s and affiliates Step 3 Generating the Octree Mesh The FLUID part appears under Parts in the display control tree Select WireFrame Full Display and rotate the geometry to confirm that the new material point is within the volume and does not just appear so from one perspective 5 Click O Solid Full Display to restore the shaded surface visualization Step 3 Generating the Octree Mesh 1 Measure the smallest diameter on the aorta geometry You will use this value to set the minimum size for the mesh a Zoom in to the smallest diameter in the graphics display b Click P Measure Distance and select a pair of locations to measure the diameter Figure 207 Meas uring the Smallest Diameter p 271 Figure 207 Measuring the Smallest Diameter locations selected for measuring the diameter The distance is reported to be around 1 5 2 Assign the mesh sizes Mesh gt Global Mesh Setup Kia gt Global Mesh Size B ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 271 Tetra Prism Mesh Generation for an Aorta Global Mesh Setup G Global Mesh Parameters a BlCVHS Global Element Scale Factor Scale factor Booo l Display Global Element Seed Size Max element 2 Display Curvature Proximity Based Refinement V Enabled Min size limit fos Display Elements in gap f
209. s for O grid Press the middle mouse button to accept the blocks Click AN Select edge s Select the edges along the ground under the car Press the middle mouse button See Figure 39 Blocks and Edges for O grid p 52 Create an O grid ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 51 Hexa Mesh Generation for a 2D Car Figure 39 Blocks and Edges for O grid g Enable Around block s h Ensure that Offset is set to 1 and click Apply i Disable VOREN in the Display Tree Figure 40 External O grid around the Car p 52 shows the O Grid passing through the floor Figure 40 External O grid around the Car 52 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Refine the Mesh using Edge Parameters Refine the Mesh using Edge Parameters In this step you will manually improve the mesh quality by adjusting the node distribution along critical edges 1 Set the edge meshing parameters Blocking gt Pre Mesh Params amp gt Edge Params ra a Select one of the radial edges of the O Grid as shown in Figure 41 Edges for setting Edge Paramet ers p 53 Figure 41 Edges for setting Edge Parameters Radial Edge in Ogrid for Selection Vertica
210. s reserved Contains proprietary and confidential in 274 formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Generating the Octree Mesh Figure 208 Octree Mesh for the Aorta Note Some solvers may not like the volume transitions in the Octree mesh Step 4 explains how you can replace the Octree volume mesh with a Delaunay volume mesh for smoother volume transition 7 Use cut planes to examine the mesh a Select Wire Frame Mesh Shells Wire Frame b Select Manage Cut Plane Mesh Cut Plane Manage Cut Plane c Set the following parameters Retain the selection of by Coefficients in the Method drop down list ii Set Fraction Value to 0 95 iii Click Apply d Enable the display of volumes in the display control tree Mesh Volumes ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 275 Tetra Prism Mesh Generation for an Aorta e Select Solid amp Wire Mesh Volumes Solid amp Wire Zoom in to view the cut plane Figure 209 Cut Plane in Z Direction for the Octree Mesh p 276 Figure 209 Cut Plane in Z Direction for the Octree Mesh f Examine the mesh using a cut plane in the X direction i Select Middle X Plane in the Method drop down list ii Set Fraction Value to 0 62 iii Click Apply Manipulate the display to obtain the view shown in Figure 21
211. s reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 145 Hexa Mesh Generation for an Elbow Part Blocking Associations 9 Edit Associations a BOGS KDL P m Snap Project Vertices Vertex Select AllVisible C Selected w S Move 0 Grid nodes z a Ensure that All Visible is selected for Vertex Select b Click Apply c Display the right view View gt Right The blocking will be oriented as seen in Figure 110 Vertices Moved Onto the Geometry Right View p 146 Figure 110 Vertices Moved Onto the Geometry Right View d Display the isometric view View gt Isometric You can also display the isometric view by clicking SHIFT I or clicking the cyan ball on the triad ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 146 formation of ANSYS Inc and its subsidiaries and affiliates Step 3 Fitting the Blocking to the Geometry The blocking will be oriented as seen in Figure 111 Vertices Moved Onto the Geometry Isometric View p 147 Figure 111 Vertices Moved Onto the Geometry Isometric View Manually move two of the vertices slightly from their present position Making these changes before creating the O Grids is much easier than doing it after because there are fewer nodes to move and internal node movement orthogonality etc do not yet n
212. s to Curves 4 So ae i K B The green arrows in Figure 10 Association of Edges to Curves p 13 point from an edge to its associated curve Nodes and vertices of these edges will project on to the associated geometry The cyan edges 42 43 34 42 38 43 do not have to be associated They are internal and will interpolate instead of project on to geometry when the mesh is computed Note If the associations do not appear correctly the edges can be reassociated to their proper curves It is not necessary to disassociate and then reassociate Associating the edge to a new curve will overwrite the previous association The steps of operation can also be retraced using the Undo and Redo buttons 4 Disable Show Association after verifying the associations Blocking Rue Edges Ee show association Step 3 Move the Vertices 1 Manually move the vertices of the inlets and outlet ends of large pipe Blocking gt Move Vertex gt Move Vertex rad ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 13 Hexa Mesh Generation for a 2D Pipe Junction Move Vertices 9 Move Vertices A PARN Z Move Vertex Method Single Vertex R Movement Constraints P Fixx Fix D Fiz F Fix direction x R EN F Move dependent Apply ERE Dismiss Note If Auto Pi
213. see only the blocking shown in Figure 116 Visible Blocks After Using Index Control p 150 Figure 116 Visible Blocks After Using Index Control b Select the blocking material parts SOLID Add to Part Select Blocking Material Add Blocks to Part chy Click B Select block s box select the entire model and click the middle mouse button to accept Alternatively click v on the keyboard to select all visible iii Click Apply The selected blocks will then be assigned to the SOLID part ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 150 formation of ANSYS Inc and its subsidiaries and affiliates Step 4 Creating the First O Grid Figure 117 Blocks Assigned to SOLID Part Note When you delete a block material or move it to another part ANSYS ICEM CFD Hexa assumes that there is a surface boundary between the blocks and auto matically applies an association to the nearest active surface for the faces at the block material boundaries You will see that the previously blue edges turn white black to indicate this Associate the O Grid edges to the cylinder curves Figure 118 Edges Projected to the Cylinder Curves p 152 Blocking gt Associate amp gt Associate Edge to Curve Co Ensure that Project vertices is enabled Associate the edges denoted C to CURVE C using Figure 118 Edges Projected to the Cylinder Curves p 152 as a guide Ass
214. sidiaries and affiliates 125 Hexa Mesh Generation for a Pipe with Embedded Blade Figure 92 Fully Split and Associated Blocking Note Vertex Color Distinction Notice that when vertices or edges are associated with geometry entities then the movement of the vertices is restricted to the associated geometry The colors of the vertices indicate their associations and degrees of freedom Vertices associated with Points are red and are fixed at a single place in the coordinate system Vertices associated to a Curve are green and can be moved on the associated curve By default all the vertices not associated with a point or curve but lying on a Surface boundary are white black if a light background and are free to move on that surface Additionally internal surfaces are blue and vertices can be moved along the blue block edges to which they are connected Generating the O Grid If the pre mesh is generated with the existing blocking the result would show badly skewed cells on the four corners of the pipe Converting the existing H Grid blocking topology to an O grid topology inside the pipe will produce a mesh that is low in skewness with orthogonal grid on the pipe walls The following steps will improve the overall mesh quality 1 Open the Split Block gt Ogrid DEZ 126 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsid
215. splay of Vertices and then under Vertices enable Numbers 3 Create the periodic relationship between two vertices Blocking gt Edit Block H gt Periodic Vertices RF a Enable Create in the Edit Block DEZ b Click Select vert s and select the vertex 411 on the periodic plane PERIODIC1 c Select the vertex 383 on the periodic plane PERIODIC2 d Click Apply This will define the periodicity between two vertices ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 208 formation of ANSYS Inc and its subsidiaries and affiliates Generate the Mesh 4 Similarly define the periodicity between all twenty vertex pairs lying on the periodic planes PERIODIC1 and PERIODIC2 5 Check that the periodic relationship has been correctly setup between vertex pairs Blocking Re vertices me periodic Figure 165 Vertex Pairs defined for Periodicity Mille y 3h i i fii P P r ai i Nf 2 n UDD as daw ix B LJAA N a y i A hit 5 78 ee 7 A y E N ES AA e f NAIA 5 3 i ATL ay 7 JA ee NTS fs ed j PAI jz TLI i ei R y j f A Kp Maa il wn cin ws i 4 i FF hs Y pi Generate the Mesh Before generating the mesh meshing parameters must be defined In this example
216. sseressseeessssresssseees 10 Step 3MOVE TNE VErtiCes arseno neii ded eoi an aE 0s E a E aS OERE ta ows EEEE e EERTE EEE EES 13 Step 4 Apply Mesh Parameters cccccccsssssscccececcessessnneeeeeeeceeseessnsaeeeeeceeeseeesnaeeeesececeseessaaeeeeeeeeeeeeenes 17 Step 5 Generate the Initial MOSH ccceessseccccecceseeeessneeeeeceeceseeesenaeeeececesseensnaeeeeeeeeseseeesnnaeeeeeeseneees 19 Step 6 Adjust the Edge Distribution and Refine the Mesh 0 cs eeeessceceesssnceecessneeeceessaeeeeessnaeeseestaeeeees 20 Step 7 Match the Edges santene nn ateas ean bsgdevestaciceancthdemtsigatenen cack de aae a a a eaat 25 Step 8 Verify and Save the Mesh and Blocking essessccsessecceseeseeceesesseecessesseceeseeseneeesesseneeseesseseee 29 Hexa Mesh Generation for a 2D Car 00 0 0 eceesceceeessceeeessnneeceessneeecessaaeeeeesaeeecessaeeseessaeeeeeesaeeseesnaaeee 31 Start a New Project and Initiate Replay Control sssssessessessssssessssseesssseessseessssresssseeessseresssseesssseessseees 31 Create and Split the Blocking to Resemble the Geometry sssssssssssssssssesssssesssssressssrresssrresssereessssreesssrress 34 Associate and Fit the Blocking to the Geometry essssssssssssessssseessssressseressssteessssressssrtessseresssereesssreessssees 42 Align the VerticeS iurarien nenese neie an eats E E E E A E aE AEE AE E aaa 45 Set Mesh Parameters and Generate the Initial Mesh ssssssssssssesssssssssssressssreessssresssseress
217. ssressssreessssreessseee 48 CAL an OOM ICH ai nae ry aea ccnp a A es e a Waa EaR A E E bane A Ua uD a E Aa a o aak 50 Refine the Mesh using Edge Parameters sssssessssseesssssessseresssssressssreesssrressseressssreesssetessseressssreessseeeesee 53 Save the Replay File and Use it for Design Iteration ssssssssssssssssssessssrersrssrtessssresssseressseressssreessssreesssrees 57 Create Output Data for a SOV efraccion n a E a a a E 60 Hexa Mesh Generation for a 3D Pipe Junction cccccccccsssssssececeeceeeeeesseeeeceecesseeesnaaeeeeeeeseseeesenaness 63 Preparati Manes rones aera iaoea Es Aad Sasi EEEE do Ba EAS es a has a ha EE EEES NEEESE NTS 64 Step Creating Partsi ssie TAE A de doses a SeLeu A a is coubvedtesteebedetusdededousy Ste aaah 64 Step 2 Creating ai Material PONE siisiasccsiawiesverseneccastaveuasetenommie Cesena E n nee E E A ET 67 Step 3 Bl cking the Geometry nosni rox os stizy ote a ctse neei wh davucs guide canineen ty tad peneh eynds Hs CaaeR iota ta eee 68 Step 4 Projecting the Edges to the Curves yids cus auadsorenauaeemiseimities mertoreuaeiaam melanie auioaear 71 Step 5 Moving the Verlices isens iinne iE e ea a A ia aai 73 Step 6 Generating the IS Fe ols pac aiao i in pcg ao EAEE A AE E E E a a 75 Step 7 Checking the Mesh Quality sssesssseessssseesssssessssseessssressssseessssreesssetessseressssstessssreessseeesssereesssstesso 79 Step 8 Creating an O Grid in the Blocking ssessssssessessess
218. ssseesssssesssseressssrerssssressssseessseresssereesssseeesssrees 80 Step 9 Verifying and Saving the Mesh sssssessssssssssssesssssesssssressssresssseressseressssseessssreesssresssereessssressssee 86 Hexa Mesh Generation for a Sphere Cube Geometry 000 0 eee ceccecesneeceeessneeecessneeeeeessaeeeeessaeeseesnaeeees 89 Preparato M sreo n 500d ccacet a E asa teen pusetseen Gites pale csvashate don auadess E A A E tenant ANEA 90 Step 1 Creating Parisar secs us sscvevsteess uiesdevevteseysesaesdevevsteess sasddevevdiversecsesieveusesese Uaestevevtesers Saesdeecvtesesse sans 90 Step 2 Creating a Material Point eas sicassssurtetesaavterssntatdalesoranniaareniossaveerrnerviveesasaeadeaomemennnnceaereed 94 St p 3 Blocking th GEOMEtEY eeaeee deat ia aa e aE E E a a i a E Aia 95 Step 4 Creating COMPOSITE CUrVeS sniadania ai a an E A OEE EAA e E AE ao EAE ER 95 Step 5 Projecting Edges to the Curves 0 ccessesssssccccceceeseeesnnececceceeseessnaeeeeeeeeseseessnaeeeeeeeeeseeeesnaaeeeeeess 97 Step 6 Moving the Vertices enii tene ee E EEEa a ARE E ERARE E AASA AEE AEEA E pata 98 Step 7 Greating the O Grid si wversainiaus crite E E AEE OE ea EEA eee E N EAE 99 Step 8 Gen rating the Meshin s areri enea a aeda a a E EE E E T aS iea i E 103 Step 9 Viewing the Scan PANS sisveis ecasttaveaeeuwens ctawedea ecuentoneuit whaineeahacas wie EEE AEE ENE ER E E aE 105 Step 10 Verifying and Saving the Mesh sesssssesssssessssssesssssesssseressseresssset
219. stribution settings should be done at the blocking level using edge parameters Step 2 Blocking the Geometry The blocking strategy for this model involves making two internal O Grids inside of an L shaped blocking e The first O Grid will capture topology specifically to create the internal cylinder hole The second O Grid will improve the mesh quality within the main elbow pipe and provide a boundary layer 1 Create the initial block gri Blocking gt Create Block gZ gt Initialize Blocks g Create Block Part FLUID a Inherit Part Name Create Block Initialize Blocks Type 30 Bounding Box v Entities o Project vertices I Orient with geometry 2D Blocking V Initialize with settings z Apply Dismiss a Ensure that Part is set to the correct material FLUID b Retain the selection of 3D Bounding Box in the Type drop down list ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 142 formation of ANSYS Inc and its subsidiaries and affiliates Step 2 Blocking the Geometry You need not select entities when creating a bounding box around the entire geometry c Ensure that Orient with geometry is disabled d Click Apply to initialize the block around the entire geometry 2 Split the initial block Blocking gt Split Block gt Split Block a Enable Curves in the display control tree b Ensure that
220. t should be collapsed In this case it is the shortest edge of the selected blocks e Click amp Select Block s and then select the blocks in front of and behind the blade as shown in Figure 88 Blocks for Collapse p 122 Figure 88 Blocks for Collapse Select Edge B NN Ca Select Blocks x FLUID f Click Apply After collapsing the model should be as shown in Figure 89 Collapsed Blocks p 123 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 122 formation of ANSYS Inc and its subsidiaries and affiliates Fit the Blocking to the Blade geometry Figure 89 Collapsed Blocks FLUID Fit the Blocking to the Blade geometry Associating edges and vertices ensures the mesh will respect the geometry entities which allows for simpler mesh refinement and more rapid design iterations 1 Associate Edges to Curves on the Blade Blocking gt Associate amp gt Associate Edge to Curve e Make sure Project Vertices is disabled in the Blocking Associations DEZ a Click a Select edge s and then click two adjacent edges on the side of the blade See Fig ure 90 Select Edges and Curves for Association p 124 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 123 Hexa Mesh Generation for a Pipe with Embedded Blade Figure 90 Select Ed
221. te the mesh Check the quality of the mesh Blocking gt Pre Mesh Quality Histogram ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 167 Hexa Mesh Generation for an Elbow Part a Ensure that Determinant 2x2x2 is selected in the Criterion drop down list b Retain 0 for Min X and 1 for Max X c Retain 0 for Max Y height and 20 for Number of bars d Ensure that Only visible index range is disabled e Enable Active parts only f Click Apply g Select the lower value bars to see the skewed cells Figure 136 Worst Cells in the Pre Mesh p 168 Figure 136 Worst Cells in the Pre Mesh 0 0 1 Oe aa OO OBO De oe 1 You can see the improvement in mesh quality The skewed cells are those which have a greater aspect ratio You can reduce this by adjusting the nodes on the corresponding edge 5 Improve the quality by adding elements in the direction of the skewed cells Blocking gt Pre Mesh Params y gt Edge Params ra a Select the edge near the skewed cells see Figure 137 Edge Selected to Improve Quality p 169 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 168 formation of ANSYS Inc and its subsidiaries and affiliates Step 8 Generating the Mesh Figure 137 Edge Selected to Improve Quality selected Increase the num
222. ted by A Click the middle mouse button to accept the selection When selecting multiple curves the first curve selected determines the curve color of the final grouped curve To avoid confusion with green edges experts try to avoid selecting the green curve segments first c Click Apply in the Associate Edge gt Curve DEZ Similarly associate the three edges in the front of the large cylinder B with the three curves forming the large semicircle B Associate the three edges on the Y plane near the cylinder intersections C with the semicircle curve forming the intersection C 72 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 5 Moving the Vertices 5 Associate the side rear edges of the large cylinder D E to the curves forming the rear ends D E respectively 6 Verify that the correct associations have been set Figure 54 Projection of Edges to the Associated Curves p 73 Blocking Edges Show association The display of Surfaces has been enabled in Figure 54 Projection of Edges to the Associated Curves p 73 Figure 54 Projection of Edges to the Associated Curves 7 Disable Show association Blocking Edges Show association Step 5 Moving the Vertices 1 Move all the vertices onto the geometry qo Blocking gt Associate gt Snap Project Vertic
223. tessssseesso 296 Merging the Tetra Mesh with Hexa Mesh at Interface2 ssssseesssssesssssessssserssssressssreessseressseressssrressssees 301 Cleaning up and Saving the Project sssssssessessssseessssressssseesssstesssetessssrtessssressssetesssetessssteesssreesssseessee 302 Multizone Mesh in HVAC Square to circle Transistion Duct ccccccssscccccceeeeesessneceeeeeeeeseeesnneeees 305 PYG Pale the Geometry mesni aiseee seati eeaim Sane aE pane do Lae nani heanbeta ceiangas Glnginctaleaeane 305 Set up Global and Part Parameters cccccccsssssssnccceccesssessnneeeceeceeeseessneaeeeceeeeseeessnaeeeeeeeeeeeeesnnneeeeeees 306 Create Automatic Surface Blocking eesssssesssssesssssesssssressssreesssrtessseressssseessstressssttessseressssreesssreeesseeees 308 Convert the Surface Blocking to 3D Blocking sssscceesserceesessncessessnseeseesonseesenseneeesesseseeseeseeseesense 310 Checking the Mesh Saving and Exiting essssessesseesssssesssssesssssresssereessstessssreessseresssereesssreessseressssseesse 313 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates v vi ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Hexa Mesh Generation for a 2D Pipe Junction In t
224. the front bumper Your vertex number may be different depending on the order in which the splits were applied b Enable Modify Y only c For Vertices to Set click R Select vert s and then select Vertex 74 Click the middle mouse button to accept d Click Apply The second vertex will be moved vertically to line up with the reference vertex as shown in Fig ure 34 Aligned Left Vertices p 47 Figure 34 Aligned Left Vertices ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 47 Hexa Mesh Generation for a 2D Car Set Mesh Parameters and Generate the Initial Mesh 1 2 Apply Mesh Parameters Mesh gt Curve Mesh Setup AL gt Select curve s amp 2 Click 4 Select items in a part in the Select Geometry toolbar that appears You can also type Shift P The Select part dialog box will open Figure 35 Select Part Dialog box m Select part Accept All None Screen Cancel Set the curve mesh size for CAR i Enable CAR and click Accept ii Set Maximum size to 25 in the Curve Mesh Setup DEZ iii Click Apply Set the curve mesh size for the wind tunnel parts i In the Select part dialog box Enable GROUND INLET OUTLET and TOP Disable CAR and click Accept ii Set Maximum size to 500 in the Curve Mesh Setup DEZ iii Click Apply Update the Mesh Paramete
225. the height while the number is the height ratio 76 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 6 Generating the Mesh Figure 56 Hexa Mesh Sizes 3 Update the mesh The hexa blocking file bIk is different from the ANSYS ICEM CFD geometry file tin You can set the entity mesh parameters at any point before or after blocking The Update Sizes command is a quick and easy way to translate the entity parameters from the geometry to the blocking Mesh counts are propagated through a mapped mesh Hence the smallest size across any index is used Blocking gt Pre Mesh Params Update Sizes Pre Mesh Params Ga Meshing Parameters a patie AN gt Qs GIO S Recalculate Sizes Method Update All Keep Distributions Keep Counts Curve gt Edge bunching M Run Check Fix Blocks Apply Dismiss a Retain the selection of Update All and select Run Check Fix Blocks 2 b Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 77 Hexa Mesh Generation for a 3D Pipe Junction c Enable Pre Mesh Blocking Pre Mesh The Mesh dialog box will appear asking if you want to recompute the mesh Click Yes Mesh is currently out of date recompute
226. thout any need to Undo any command You should also click Renumber if you use Clean ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 41 Hexa Mesh Generation for a 2D Car The blocking lines are those start with ic_hex_ For example if you scroll through the window you should see ic_hex_set_edge_projection 11 13 0 1 INLET 1 the command that created the association of edge 11 13 to curve INLET 1 Before proceeding with this tutorial be sure the last line in the Replay Control window is highlighted and Record after current is enabled Associate and Fit the Blocking to the Geometry To ensure proper projection of the blocking edges onto the geometry project block vertices to the prescribed points and block edges to the curves 1 Enable the display of Points and Vertices LMB I Points LMB I Vertices Ensure vertex numbers and point names are enabled displayed 2 Associate the Vertices to the Points Blocking gt Associate amp gt Associate Vertex oe a Ensure that the selected Entity is Point in the Blocking Associations DEZ b Click Ss Select Vert s and then select vertex 55 at the rear of the roof line You may have different vertex numbers depending on the order in which the splits were applied The important goal is to make the blocking more closely follow the shape of t
227. tion of point to complete second block d Click middle mouse button to accept the selection e Click Apply The blocking after creating second block is shown in Figure 149 First Two Blocks ad ded p 192 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 191 Bottom Up Hexa Mesh Strategy for a Grid Fin 3 Figure 149 First Two Blocks added Continue creating blocks all the way around the central Shell part Use the following table and Fig ure 150 Complete 2D blocking p 193 as a guide Note e You may temporarily disable entities in the Display tree to help with locating vertices and points Select Vertices and Points in the order listed Select existing Vertices before clicking the middle mouse button second middle mouse Then select the remaining points to outline the block before the button New vertex numbers are assigned when Apply is clicked and the block is created Select existing Vertices in or Select location in or der der 45 67 122 123 67 65 123 136 99 11 149 150 11 47 150 165 47 45 165 180 192 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Extrude a 2D Planar Grid to Create 3D Blocking 45 122
228. to Show Composite To view the surface mesh enable Pre Mesh under Blocking in the Display tree Allow recalculate when prompted ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 309 Multizone Mesh in HVAC Square to circle Transistion Duct Figure 232 Initial Surface Mesh on HVAC Transition Duct Disable Pre Mesh before proceeding Convert the Surface Blocking to 3D Blocking The surface blocking is inflated to create the 3D blocking in the volume 1 Extrude 2D Blocking Blocking gt Create Block amp gt 2D to 3D 2 In the Method drop down list select MultiZone Fill 3 Enable the Create Ogrid around faces checkbox 4 Click Select Part s In the Select Parts dialog box Duct is checked The default selected parts are set by the Prism settings in the Part Mesh Setup dialog earlier Click Accept The Offset distance is calculated from the Prism settings The display shows the average but the actual offset will be calculated part by part 5 For Fill Type Method choose Advanced from the drop down list ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 310 formation of ANSYS Inc and its subsidiaries and affiliates Convert the Surface Blocking to 3D Blocking Advanced will create mapped blocks wherever possible front and b
229. to delete disconnected vertices click Yes b Click Apply Smooth the mesh ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 227 Tetra Prism Mesh in a Fin Configuration Edit Mesh gt Smooth Mesh Globally amp Figure 177 Initial Quality Histogram for Tetra Prism Mesh 1 I l l 1 l I 1 0 0 1 0 2 0 3 0 4 0 5 0 6 07 0 8 0 9 1 Several elements have a lower quality than the acceptable value of 0 3 a For Smoothing Iterations enter a value of 5 b For Up to Value enter a value of 0 4 c For Criterion select Quality from the drop down list d Inthe Smooth Mesh Type selection box i Select Smooth for TETRA_4 TRI_3 and QUAD 4 ii Select Freeze for PENTA_6 Note By initially freezing the Penta_6 layer you can smooth the rest of the tetra tri mesh without damaging the prism layer which is important to capture the boundary layer physics e Click Apply A new histogram appears showing some changes have occurred 3 Re run the smoothing this time including the PENTA_6 elements a Change the Up to Value to 0 2 to prevent dramatic distortion of the prism layers b Select Smooth for the PENTA_6 type c Click Apply ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 228 formation of ANSYS Inc and its subsidiaries and
230. to select all the points b Ensure that Delete Permanently is disabled c Click Apply 6 Use the Build Diagnostic Topology option to establish connectivity Note This will create the connectivity you will need later for grouping the tangential curves Step 4 Creating Composite Curves p 95 Geometry gt Repair Geometry N gt Build DiagnosticTopology ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 92 formation of ANSYS Inc and its subsidiaries and affiliates Step 1 Creating Parts Repair Geometry neo Ez IV Inherit Part CEEE Eoee Build Topology Tolerance 0 02 m Filter by angle Feature angle 30 IV Filter points IV Filter curves Build Topo Parts Selection Method All parts v Part by part Single curve cleanup ey V Split surface at T connections F Split facets at interior curves Join edge curves MV Delete unattached curves and points Keep dormant as dormant F Use Local Tolerance Apply Dismiss a Ensure that Inherit Part is enabled b Enable Filter points and Filter curves c Retain the other settings and click Apply Note The build topology establishes connectivity and places the curves in an inherited part name This is not as critical here where only a few curves would need to be placed into a part but could be very useful in a really large model where interactively
231. troid of 2 points C At specified point 2 screen locations 43 9961 R EREI Dismiss 1 Enter FLUID for Part 2 Ensure that Points is enabled in the display control tree 3 Click amp Select location s and select two locations such that the midpoint lies within the volume Figure 50 Selection of Points for Creating Material Point p 68 Click the middle mouse button to accept the selection of the points ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 67 Hexa Mesh Generation for a 3D Pipe Junction Figure 50 Selection of Points for Creating Material Point Points selected for creating the material point 4 Click Apply so that FLUID appears under Parts in the display control tree Rotate the model to confirm that the new material point is within the volume and does not just appear so from one perspective Note Parts such as GEOM will be deleted when they no longer contain any entities 5 Save the geometry file 3d pipe geometry tin File gt Geometry gt Save Geometry As Step 3 Blocking the Geometry The blocking strategy for the 3D pipe geometry involves creating two blocks from the initial block one each for each half cylinder forming an L shaped configuration You need to create an O Grid to improve the mesh quality The blocking functionality in ANSYS ICE
232. tter to have the fewest number of blocks possible You can reduce the number of blocks by following these steps ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 212 formation of ANSYS Inc and its subsidiaries and affiliates Reduce the Blocks in a Multiblock Mesh Figure 168 Complete Blocking prior to Reducing the Number of Blocks vu S i S l v 2 gos ps 2 s 2 2 2 6 2 a 7 O CARDA by 3 Q 3 X lc A 7 F Fe g oF WAAAY YY og P28 G C gt a E eo i re A A AN a Z 2 Fe ee eae 7 a w S oe a a SS ark Fa U e 2 gt ESS SS SSS a eae j io T A EAH EES VARAA Z NAANA o G 8 ALK SESS SAV TE E ea v v EA AA oer A D aTi A7 a i S 2 ist Z 7 2 G 5 3 2 tf a s Ww amp Wm N 213 formation of ANSYS Inc and its subsidiaries and affiliates Pre Mesh ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in LMB Disable the display of Vertices Disable Pre Mesh Blocking 3 4 Bottom Up Hexa Mesh Strategy for a Grid Fin Blocking Vertices 5 Merge the unnecessary blocks Blocking gt Edit Block B gt Merge Blocks 7 a Select Automatic for Merge Blocks b Click Apply Note Merging blocks will normally affect the mesh but if done after Initializing output blocks and displaying Output Blocks it will not affect the
233. tutorial If not see the notes at the end of this section 2 Start ANSYS ICEM CFD and open the geometry Elbow agdb File gt Workbench Readers a Select Elbow agdb in the Select Workbench Import File dialog box and click Open ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 138 formation of ANSYS Inc and its subsidiaries and affiliates Preparation Import using Workbench Readers 9 Parts Sizes aj Workbench defaults From tetin file MV Import Geometry aa Geometry Preferences Create Subset s from Named Selection F Create Material Points MV Import Solid Bodies V Import Surface Bodies I Import Line Bodies MV CAD Attribute Transfer CAD Attribute Prefixes E DFEA DDM V Named Selection Processing Named Selection Prefixes IV Enclosure and Symmetry Processing eo Fa be de Convert Units Apply ox Dismiss Ensure that Import Geometry is enabled Retain the other default settings and click Apply The DesignModeler file is now read into ANSYS ICEM CFD Enable Surfaces in the display control tree Geometry Surfaces Note If you don t have Workbench Readers use File gt Geometry gt Open Geometry to open the native ANSYS ICEM CFD file Elbow tin You will also need to create the parts EL BOW_1_1 CYL INLET and OUTLET as well as Delete unattached curves Refer to the ANSYS ICEM CFD 14 5 SAS IP Inc Al
234. ure outlet exhaust fan outlet vent solid symmetry velocity inlet Cancel ii Select wall from the list of Boundary Conditions in the Selection dialog box iii Click Okay iv Enter the zone ID if required ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 171 Hexa Mesh Generation for an Elbow Part b Similarly set the boundary conditions for INLET to velocity inlet and OUTLET to pressure outlet exhaust fan outlet vent c Set the boundary conditions for FLUID to fluid and SOLID to solid Family boundary conditions FLUID af solid Create new Zone id jo Paste one Boundary Conditions Delete Copy bY fluid SOLID Create new Paste Boundary Conditions Vv E Surfaces Zf One sided afi Two sided Mixed unknown INLET Create new Paste Boundary Conditio ona velocity inlet OUTLET Create new Paste Boundary Conditio pressure outlet Create new Paste Boundary Conditions wall Accept Cancel d Click Accept after setting the boundary conditions Note Mixed unknown refers to the dimension of the elements in a part If a part contains all volume elements it clearly belongs in the Volumes branch Similarly parts in the Surfaces branch should contain only shell elements and the Edges branch should contain only curve elements and so on However if a part has a mixture
235. ve the Cut Plane back and forth in the z direction to examine the mesh behavior around the Blade d Change the Method to Middle Y plane See Figure 104 Mid Y Cut Plane p 136 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 135 Hexa Mesh Generation for a Pipe with Embedded Blade Figure 104 Mid Y Cut Plane e Scroll the Cut Plane up and down through the pipe f Click Dismiss when finished examining Cut Planes Re enable Pre Mesh in the Display tree Saving 1 Select File gt Blocking gt Save blocking As and enter a suitable name such as pipe_blade blk Saving the blocking will allow the user to change any meshing parameters yet quickly restore a known state by reloading the blocking onto the geometry Write the mesh in an unstructured or structured format Blocking Pre Mesh Convert to Unstruct Mesh Blockin Pre Mesh Convert to MultiBlock Mesh g This will write the mesh to an output file using the default file name in the working directory and im mediately load the mesh ANSYS ICEM CFD allows you to save your mesh in a format needed for your solver Select File gt Save Project 136 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Hexa Mesh Generation for an Elb
236. ve the project file 3D pipe geometry final prj File gt Save Project As Exit the current session File gt Exit ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 87 88 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Hexa Mesh Generation for a Sphere Cube Geometry In this tutorial you will employ an O Grid to fit the topology of the region between a cube and a sphere The O Grid forms a topological bridge between the dissimilar topologies and provides excellent element quality Figure 65 Sphere Cube Geometry This tutorial demonstrates how to do the following Create parts for the geometry Create the material point e Block the geometry Create composite curves Project edges to the curves e Move the vertices Create the O Grid Fit the O Grid using prescribed points e Generate the mesh ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 89 Hexa Mesh Generation for a Sohere Cube Geometry e View scan planes e Verify and save the mesh Preparation Step 1 Creating Parts Step 2 Creating a Material Point Step 3 Blocking t
237. vertex will immediately snap to the selected point and the point will turn red Red means a fixed vertex which can not be moved unless the association is changed v Similarly capture the remaining corners making the block fit the cube see Figure 74 Inner Block Fit to the Cube p 101 3 Associate the edges of the central block to the underlying curves of the cube geometry Note Without this step the sharp feature nodes will be simply surface projected This will cause problems for the smoother and may also cause boundary condition issues with some solvers Blocking gt Associate amp gt Associate Edge to Curve O a Click Select edge s and select an edge of the central block Click the middle mouse button to accept the selection b Click amp Select compcurve s and select the underlying curve on the cube geometry Click the middle mouse button to accept the selection c Click Apply d Similarly associate the remaining edges to the curves of the cube Figure 74 Inner Block Fit to the Cube p 101 Figure 74 Inner Block Fit to the Cube p 101 shows the inner O Grid block fit to the cube geometry Figure 74 Inner Block Fit to the Cube ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 101 Hexa Mesh Generation for a Sphere Cube Geometry 4 Delete the unnecessary central blo
238. xactly as this tutorial describes you should go to the Settings Menu click Selection and disable Auto Pick Mode in the DEZ Most experienced ICEM CFD users prefer to enable Auto Pick Mode as it improves efficiency See the Selection menu help for more detail Blocking Strategy The blocking strategy for the 2D pipe geometry involves creating a T shaped blocking and fitting it to the geometry The 2D pipe geometry is equivalent to a T shape with the right side of the blocking crossbar bent upward to resemble the geometry You will fit the T shaped blocking to the geometry by creating associations between the edges of the blocks and the curves in the geometry and then moving the vertices of the blocks onto the corners of the geometry This procedure will be described in subsequent steps ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in 2 formation of ANSYS Inc and its subsidiaries and affiliates Step 1 Block the Geometry Figure 2 The Mesh and its Topology Step 1 Block the Geometry The geometry and part information has already been defined for this tutorial You will create the initial block in this step 1 Create the initial block Blocking gt Create Block amp gt Initialize Blocks g Create Block 9 Part FLUID pa pee fE ak Z Initialize Blocks Type 20 Planar X Initialize with settings
239. xt to Vertices to Set and select the other 3 vertices You can select the vertices by block selecting all of them Click Apply All the vertices will be aligned such that they have the same Y value Figure 120 Moving the Vertices on the Cylinder p 155 154 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 5 Adjust the O Grid Edge Length to Improve Quality Figure 120 Moving the Vertices on the Cylinder reference vertex LID 4 FLUID a EEE ae E r a gt me a a ON AT bess LAA 7 4 Align the vertices to the base plane Bea BENE Blocking gt Move Vertex gt Align Vertices tiik ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 155 Hexa Mesh Generation for an Elbow Part Move Vertices D Move Vertices a PAN Z Align Yertices Along edge direction fos 105 1 amp Seas Coordinate system Cartesian v Move in plane CZ amp KX C XY User Defined Apply eon Dismiss a Click a Select edge s and select an edge along the Y direction for Along edge direction see Figure 121 Aligning Vertices p 156 b Click Select vert s and select the vertex at the base of the edge on the base
240. y Figure 192 Overlapped Surfaces and Slivers Create an assembly for all the fuselage surfaces Rue gt parts EEH create Assembly Create Assembly 9 Assembly name FUSELAGE Create Assembly FIE Create Assembly by Part Selection Apply EEI Dismiss a Enter FUSELAGE for Assembly name in the Create Assembly DEZ b Click 3iselect part s The Select parts dialog will appear c Select all the parts except FF and BIGSYM in the Select parts dialog box and click Accept d Click Apply in the Create Assembly DEZ Extract the feature curve from the symmetry plane Geometry gt Create Modify Curve au gt Extract Curves from Surfaces A ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates 249 Tetra Prism Mesh Generation for a Helicopter Create Modify Curve eem o w V Inherit Part aes 5 we HOP KO Surfaces caac ryt piece Surface Type BSpline Faceted Extract Edges Check Topology C Create New i Apply Loi Dismiss a Disable all parts except the symmetry BIGSYM in the display control tree b Click B Select surface s and click Select all appropriate visible objects in the selection toolbar You need not click the middle mouse button when using the Select all appropriate visible objects option You can also type v to select visibl
241. y are above the solver require ments you can proceed Typically exceeding 0 1 for a determinant and 9 to 18 degrees for angle is sufficient Step 9 Saving the Project Save the blocking file File gt Blocking gt Save Blocking As Save the mesh in unstructured format with the default name hex uns to the working directory Blocking Pre Mesh Convert to Unstruct Mesh The mesh will automatically be loaded Write the input file for ANSYS FLUENT 170 ANSYS ICEM CFD 14 5 SAS IP Inc All rights reserved Contains proprietary and confidential in formation of ANSYS Inc and its subsidiaries and affiliates Step 9 Saving the Project Output gt Select solver gt Solver Setup P Output Solver ANSYS Fluent E a Structural Solver NASTRAN P Set As Default Apply ERa Dismiss a Select ANSYS Fluent from the Output Solver drop down list b Retain NASTRAN in the Common Structural Solver drop down list This selection is not important for this tutorial since we are only outputting the mesh to ANSYS FLUENT and not using the structural mechanical setup at all c Click Apply Set the appropriate boundary conditions Output gt Boundary conditions fay a Set the boundary condition for ELBOW_1_1 to wall i Click Create new under ELBOW_1_1 Selection Select a BC type fw tt i st A mass flow inlet outflow periodic pressure far field pressure inlet inlet vent intake fan press

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