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Mesh Generator

1. Figure 1 5 The blunt body with boundaries in place 1 3 3 Creating the Mesh With the boundaries defined you are now ready to create the mesh To do this perform the fol lowing steps Chapter 1 Getting Started 1 Use the Mesh menu to select the create Algebraic Elliptic Structured The Mesh menu is shown in Figure 1 6 The Algebraic Elliptic Structured dialog offers three methods for Hesh Generator E File Boundary Create Algebraic E lipti Structured Create Hyperbolic Structured Mesh Gene Create Unstructured Bg 2D Eqit selected Mest Delete Selected Mesh Close Help Figure 1 6 The Mesh menu inserting boundaries into the four mesh boundary zone fields The information can be entered manually by clicking Add From List and selecting the appropriate boundary line from the menu or by using the Tecplot Selector tool to select a boundary line and then clicking Add Selected Ensure that no zones are selected in the current Tecplot frame by clickin
2. 7 The Unstructured mesh around the airfoils 5 Accept all other defaults if desired add an appropriate label then click Create The Work ing dialog will appear while the mesh is generated The resulting mesh is shown in Figure 7 7 showing the area 9 Figure 7 Select the mesh by clicking on a node using the Tecplot Selector tool Then choose Edit number of cells used If the mesh has not met the internal optimization requirement within the Selected Mesh from the Mesh menu specified number of cells you will get a message stating the optimal structured mesh requires more than the Maximum Cells specified You can either accept the mesh as generated or edit it Unstructured mesh creation in Mesh Generator uses an internal mesh optimization scheme If the optimal mesh is reached before the value you have set for Maximum Cells is reached you will get a message stating that the optimal unstructured mesh has been created it will list the 7 3 6 Editing the Unstructured Mesh To edit it perform the following steps 1 110 7 4 Three Element Airfoil Example with a Modified C Mesh 2 For our example the optimization factor is met with a Maximum Cells value of 40000 On the Unstructured dialog set Maximum Cells to 40000 then click Replace The Working dialog will appear while the mes
3. 5 0 5 X Figure 3 4 The Hyperbolic Structured mesh The working dialog features a Cancel button Clicking Cancel stops the mesh generation at the last iteration but does not delete the new mesh zone Note During the recording of a macro or project file a Cancel request is not recorded If a project file is saved at this point however only the number of layers actually generated will be saved in the file 54 3 3 Editing and Deleting Structured Meshes 3 3 Editing and Deleting Structured Meshes To edit a mesh you may Select it in the current Tecplot frame and then choose Edit Selected Mesh from the Mesh menu Depending upon the type of mesh you have selected either the Algebraic Elliptic Structured or Hyperbolic Structured dialog will be called up Edit Selected Mesh is only active when the mesh you have selected was created by Mesh Generator To edit the Hyperbolic Structured mesh you have created perform the following steps 1 Select the hyperbolicy mesh in your current Tecplot frame with the Selector tool then choose Edit Selected Mesh from the Mesh menu 2 In the Mesh Control area of the Hyperbolic Structured dialog set Total Distance to 3 and use the Min drop down to set the value as X Constant Set Max Smoothing Passes to 0 3 Finally use the Mesh Label text field to name the new mesh hyperbolicx Click Replace The Working dialog will appear while the mesh is regenerate
4. The first word within the character string SBPATCH indicates that this is a boundary patch on a structured mesh The integer which follows this 3 indicates that this patch is on the third mesh within the file that is the third mesh of those you chose to output The next word Wall is a label by which the patch is identified This is the label of the corresponding boundary and commonly represents a boundary condition which the analysis software will apply to this boundary region Following the patch label are three additional integers The first 2 indicates that this region resides on the J face of the mesh The second 1 indicates that this region begins at the first node of this face and the final integer 6 indicates that the sixth node of the face is the final node of the region Note The number 1 indicates the face 2 indicates J 4 indicates Max and 5 indi cates J JMax In three dimensional meshes generated by other programs 3 and 6 would be used for the K and K KMax faces of the mesh 5 1 1 3 DBPATCH The DBPATCH USERREC is used to identify a region on the boundary of an unstructured mesh Like the SBPATCH It contains the zone number of the mesh and a label Following these it contains the number of cell edges which make up the region and pairs of node numbers which form each cell edge Since many node numbers may be required follow on USERRECs may be used to contain them This is illustrated below
5. 6 On the Circular Arc dialog use the Line Label text field to name this circle then click Create Close the dialog 7 4 6 Creating the Unstructured Mesh We are now ready to create the unstructured mesh To create this mesh perform the following Steps 1 Select Create Unstructured from the Mesh menu Unstructured mesh boundaries must be entered as closed loops For this example there will be a total of four closed loop bound aries This means there will be four entries in the Closed Loop Boundary list On the Unstructured dialog click New Boundary This will enter Incomplete into the Closed Loop Boundary list Now click Add From List In the list presented highlight sa sb sc and sd the outer boundaries on the slat then click OK In the Closed Loop Boundaries list Incomplete will have changed to Int Boundary followed by the four zone numbers of the boundary Click New Boundary and repeat the process adding wa wb wc and wd the outer bound aries on the wing to your new boundary Repeat the process once more for the outer bound aries on the flap fa fb fc and fd Click New Boundary and this time use Add From List to add circle Click Reverse Direc tion Notice that Int Boundary changes to Ext Boundary Accept all other defaults and add the appropriate mesh label Click Create The Working dialog will appear while the mesh is generated The resulting mesh is shown in Figure 7 9 Compare t
6. then click Create 10 Now change the Distribution for b1 and b2 to Even Spacing and set Number Of Nodes equal to 30 The resulting boundaries are shown in Figure 2 6 2 4 Importing Boundary Files For situations where the boundary definition exists as a file containing X and Y coordinates or an IGES NURB definition created by CAD software you can import data to create bound aries within Mesh Generator 2 4 1 Loading Tecplot Data Files If the boundary is defined by pairs of X and Y coordinates in a file that can be read by Tecplot you can load the file using Load Data File s This is found under the File menu on Tecplot s menu bar The data can be lines I ordered zones or meshes IJ ordered zones These exist as Tecplot zones and may be used to create boundaries for new meshes which will be discussed in later sections The imported files can also be used directly as boundaries provided their node distributions are sufficient 29 Chapter 2 Creating Boundaries S YN O A A O Figure 2 6 Modified blunt body with elliptic outer boundary 2 4 2 Importing NURB Files This utility allows you to read a curve from a NASA IGES NURB ONLY file To call up the Read IGES File dialog click File on the Mesh Generator menu then select Import NURB File from the list The Read IGES File dialog will appear as shown in Figure 2 7 This is a standard file in
7. The resulting Laplace mesh is shown in Figure 1 10 LLII LLZ L LL LLIT F TZ LLLI LLLI AILA I LEER Yee 77 LZ LL X ERIS TTL O_O F FEES a r me A A A AL A A A A A A A AL Al A AL AA O sn tn nt rn nr nr nn on S i R R 1 O R 1 O S 1 S S i O R i O S i 1 S i E Figure 1 10 The modified Laplace mesh 1 4 3 Converting Meshes Mesh Generator can convert structured meshes to unstructured meshes quickly through its mesh conversion capabilities To do this select the File menu then select the Write Mesh File This will call up the Mesh Output dialog Here you have the option of selecting either Single 14 1 5 Saving Your Work Triangular or Single Quadrilateral Zone conversion which may be performed on selected meshes in your current Tecplot data set The Mesh Output dialog is shown in Figure 1 11 Hesh Output Ed Format Tecplot ASCII Binary Mesh Conversion f Mone Single Triangular Zone Single Quadrilateral Zone 8 Unstructured surface 8 OK Cancel Help Figure 1 11 The Mesh Output dialog Note Mesh conversion can be performed for PLOT3D files however PLOT3D files do not contain any boundary information Also PLOT3D files may contain either structured or unstructured zones not both 1 5 Saving Your Work There are four options on Mesh Generator s File menu which are associated with input output These are e Import NURB file 15 Chapter 1 Getting St
8. ATTIC Mesn Generator Version 1 2 User s Manual Copyright 1988 2003 Amtec Engineering Inc All rights reserved worldwide Except for personal use this manual may not be reproduced transmitted transcribed stored in a retrieval system or translated in any form in whole or in part without the express written permission of Amtec Engineering Inc 13920 Southeast Eastgate Way Suite 220 Bellevue Washington 98005 U S A This software and documentation are furnished under license for utilization and duplication only according to the license terms Documentation is provided for information only It is subject to change without notice It should not be interpreted as a commitment by Amtec Engineering Inc Amtec assumes no liability or responsibility for documenta tion errors or inaccuracies SOFTWARE COPYRIGHTS Mesh Generator Tecplot RS Tecplot 1988 2003 Amtec Engineering Inc All rights reserved worldwide ENCSA Hierarchical Data Format HDF Software Library and Utilities 1988 1998 The Board of Trustees of the University of Illinois All rights reserved Contributors include National Center for Supercomputing Applications NCSA at the University of Illinois Fortner Software Windows and Mac Unidata Program Center netCDF The Independent JPEG Group JPEG Jean loup Gailly and Mark Adler gzip Bmptopnm Netpbm 1992 David W Sanderson Dlcompat 2002 Jorge Acereda additions and modifications by P
9. Mesh Generator COMMAND WRITEPROJECTFILE airfoil lay WRITEGRIDFILE Syntax ADDONCOMMAND ADDONID Mesh Generator COMMAND WRITEGRIDFILE lt string gt optional parameters 92 Macro Commands Description Write mesh zones to the file specified by lt string gt Optional Parameters Parameter Syntax Default Notes FORMAT lt gridformatoption gt TECPLOT Format in which to write the mesh file TYPE lt gridtypeoption gt ASCII ASCII or BINARY CONVERSION NONE Options to convert all output mesh zones to lt conversionoption gt a single triangular or quadrilateral mesh zone MULTIZONE lt boolean gt FALSE Only used when writing a single mesh zone to a PLOT3D file Indicates whether multi zone format should be used If FALSE the single zone format will be used ZONELIST lt sef gt All zones The Tecplot zones to write to the file Example 1 Write mesh file airfoil dat in Tecplot ASCII format containing zones 1 3 4 and 5 ADDONCOMMAND ADDONID Mesh Generator COMMAND WRITEGRIDFILE airfoil dat ZONELIST 1 3 5 Example 2 Write mesh file airfoil g in PLOT3D binary format combining zones 1 3 4 and 5 into a single triangular zone ADDONCOMMAND ADDONID Mesh Generator COMMAND WRITEGRIDFILE airfoil g FORMAT PLOT3D TYPE BINARY CONVERSION TRIANGULAR ZONELIST 1 3 5 93 Chapter 6 Extended Macros 6 4
10. Accept all other default values and click OK 5 Use the Line Label text field to name this polyline b6 then click Create 6 Create an additional polyline with a start point coincident with the starting node of b6 at 5 0 and its end point at 10 0 Click Node Distribution and set Distribution to Even Spacing and Number Of Nodes to 30 Accept all other default values and click OK 7 Use the Line Label text field to name this polyline b7 then click Create 27 Chapter 2 Creating Boundaries 8 Create a new polyline b8 with its start point coincident with the end point of b7 at 10 O and 10 6 with 49 evenly spaced nodes 9 Create one more polyline with its start point coincident with the end point of b4 at 5 6 and the end point of b8 at 10 6 Set Distribution to Even Spacing and Number Of Nodes to 30 Use the Line Label text field to name this polyline b9 The new boundaries are shown in Figure 2 5 b9 O NW A OA O NO O Figure 2 5 The modified blunt body Since we want a different outer boundary on the front end of our blunt body we will need to modify two of the existing boundary lines and replace them One way to do this is to simply delete the zone 1 Ifthe mesh named laplace is present use the Tecplot Selector tool to select it then select the Delete Selected Mesh option from the Mesh menu Then using the Tecplot Selector tool select polyline b3 in the current Tecplot frame
11. Mesh Generator allows you to modify your existing boundaries and meshes in a number of ways As an introduction to Mesh Generator s capabilities we will now change the node distri bution and method of mesh generation on the blunt body configuration we have developed in the previous examples 11 Chapter 1 Getting Started 4 2 0 2 A X Figure 1 8 The Algebraic Arclength mesh 1 4 1 Modifying Boundaries First we will change the node distribution on the JMin boundary lines b1 and b2 then the JMax boundary line b5 To make line selection easier you may find it useful to click on the Hide 2D Mesh check box on the Mesh Generator main dialog and then click Redraw on the Tecplot sidebar The existing mesh will no longer be shown Now perform the following steps 1 2 Using the Tecplot Selector tool click on a node on bl On the Boundary menu choose Edit Selected Line This will call up the Circular Arc dia log displaying the information for b1 Click Node Distribution On the Node Distribution dialog change Distribution to Exponen tial and Number Of Nodes to 15 Accept the other values and click OK On the Circular Arc dialog click on Replace then click Close Click on b2 the second line making up the JMin boundary Then select Edit Selected Line from the Boundary menu 12 1 4 Modifying and Converting Boundari
12. The lines selected to define boundaries are shown by zone numbers in the text fields labeled IMin Max JMin and JMax corresponding to the four boundaries of the mesh Lines may be selected in one of three ways e Ifa line is selected using the Tecplot Selector tool the button next to the Min Max JMin and JMax text fields reads Add Selected Clicking the appropriate button will add this line segment s zone number to the corresponding text field e If no line is selected the button next to the IMin IMax JMin and JMax text fields reads Add From List Clicking this button invokes the Add From List dialog with a multi selec tion list of line segment zone numbers and names One or more of these items are selected in the usual way click Ctrl click or shift click Clicking OK adds the zone numbers of the selected line segments to the appropriate text field e The zone numbers of the lines may be manually entered directly into the Min IMax JMin or JMax text fields 46 3 1 Creating Algebraic or Elliptic Meshes Algebraic Elliptic Structured Boundaries Enter Mesh Boundary zone Numbers Ihin Add From List max _Add From List win Abdi Fromm List imax O Add From List Mesh Control hethad Algebraic Arclength Orthogonality Relaxation 0 1 Maximum Iterations 100 Elliptic Relaxation besh Label Create Reo ace Close Help Figure 3 1 The Algebraic Elliptic Structured
13. optional parameters RAWDATA lt clusteringrawdata gt Description Create a new mesh line whose nodes are distributed along a circular arc If MULTIPLETANH distribution is used the clustering data must be specified in the RAWDATA section See 6 5 Raw Data on page 95 for a description of lt clusteringrawdata gt 77 Chapter 6 Extended Macros Optional Parameters Parameter Syntax REPLACEZONE lt integer gt LABEL lt string gt HOWSPECIFIED lt circlespec gt COUNTERCLOCKWISE lt boolean gt XORIGIN lt double gt YORIGIN lt double gt XSTART lt double gt YSTART lt double gt XEND lt double gt YEND lt double gt ARCANGLE lt double gt RADIUS lt double gt DISTRIBUTION lt distributionoption gt NUMBEROFNODES lt integer gt REVERSELINEDIRECTION lt boolean gt Default 0 WH SPECIFYORIGIN FALSE EVENS PACING 30 FALSE Notes Zone to replace with the generated line If 0 a new line is created The zone title to apply to the created line Indicates how the circular arc will be defined If SPECIFYORIGIN set the ori gin and starting locations and the arc angle If SPECIFYRADIUS set the starting and ending locations and the radius If TRUE indicates that the arc proceeds in the counter clockwise direction X location of the arc s origin Used only if HOWSPECIFIED is set to SPECIFYORI GIN Y locatio
14. 2 5 3 Creating the Boundary The new boundary will be created and displayed in the current Tecplot frame after you click Create It will be a Tecplot I ordered zone To demonstrate this feature we will continue building on the blunt body example we last changed in Section 2 3 Conic Arcs Now we will create a new boundary line from b5 which will have a parabolic shape and more nodes To do this perform the following steps 1 Using the Tecplot Selector tool select b5 in the current Tecplot frame Now click on the Boundary menu and select Create From Selected Line This will call up the Conic Arc dia log We want to change the shape to a parabola so set Length Ratio to 0 5 Click Node Distribution On the Node Distribution dialog set Number Of Nodes to 59 Accept all other default values and click OK On the Conic Arc dialog use the Line Label text field to name this boundary b10 then click Create Close the dialog Use the Tecplot Selector tool to select b5 in the current Tecplot frame then click on the Boundary menu Select the Delete Selected Line option on the menu This will remove boundary b5 32 2 6 Extracting New Boundaries The new boundary is shown in Figure 2 8 9 8 7 6 5 A gt 3 2 1 0 1 2 3 2 0 2 4 6 8 10 X Figure 2 8 Modified blun
15. 30 and accept all other default values Click OK 3 On the Polyline dialog use the Line Label text field to name this boundary line b3 Click Create The new boundary line will be drawn in your current Tecplot frame 4 From the Tecplot menu bar select the View menu then select the Data Fit option to display all of the newly created boundary line 1 3 2 3 Creating the IMax Boundary To create the IMax boundary according to the boundary orientation rules the highest index of JMin must be coincident with IMax 1 Thus this boundary should be a polyline which begins at 5 1 and which will end at 5 6 Perform the following steps Chapter 1 Getting Started Node Distribution x Mode Distribution Option Distribution Even Spacing Number Of Nodes 2 Reverse Line Direction Go wo Sided orne sidedinitial Initial Spacing 0 004 E one sided Final Final Spacing ooo Multiple Tanh x Spacing MNodes SSE S ae Replare Aag pelete Interpolation cubic OK Cancel Help Figure 1 4 The Node Distribution dialog 1 With the Selector click on a node near the end point of b2 near 5 1 Click Select Endpt It will automatically enter the X and Y values of the nearest end point Click Insert Before Now manually enter 5 and 6 as the X and Y coordinates for the Max boundary Click Insert After 2 Click Node Distribution and set Distribution to Even Spacing Number Of
16. 67 Chapter 5 Exporting Meshes USERREC DBPATCH 3 Wall 5 USERREC 1 223 3445 5 6 The first USERREC above identifies that this is a DBPATCH on zone 3 It also uses Wall as its label and specifies that this boundary region contains five cell edges The second USERREC contains ten node numbers five pairs The first cell edge is formed by nodes 1 and 2 the second by nodes 2 and 3 and so on These node pairs may be contained in many consecutive USERRECs within the file 5 1 1 4 IZPLABEL The IZPLABEL USERREC is used to identify by label two boundary patches which the analysis software should treat as an inter mesh zone connection For exam ple The following USERREC would indicate that the SBPATCH and the DBPATCH defined in the two previous sections are connected USERREC IZPLABEL Wall Since inter mesh zone connectivity is indicated only by label it is important to use unique labels for each boundary which will represent a connection if your analysis software will be using this information 5 1 2 The PLOT3D Format PLOTS3D and its successor FAST support several similar mesh file formats For structured meshes there are two dimensional and three dimensional single and multi mesh formats For unstructured meshes there are single and multi zone formats Any of these may be ASCII or binary Binary files are written in single precision Mesh Generator supports two dimensional and unstructured single and mul
17. After using the Convert Polyline Geometry Insert After button the selected geometry is deleted from the current Tecplot frame 2 1 1 3 Using a Subset of the Specified Control Points An option to use a subset of the control points you have specified is also available You can do this by specifying the start ing and ending indices of the desired control points as they appear in the Control Points list The starting and ending indices are entered into the two text fields labeled Start and End in the Line Definition area of the Polyline dialog These are shown on Figure 2 2 The default value for the starting index is 1 and the default value for the ending index is Mx The ending index will accept any integer between and Mx as well as Mx a where a is some integer provided that Mx a is greater than or equal to 2 The starting point of the newly created polyline will be the control point defined by the Start index and the ending point will be the control point defined by the End index Any interpolations performed on the resulting polyline will be based on all of the control points you have specified in the Control Points list regardless of the start ing and ending index values 2 1 2 Node Distribution The number of nodes the distribution option and the interpolation on a boundary is set by clicking Node Distribution The button is active only after at least two control points have been specified When you click Node Distribution the Node Dis
18. All mesh output options are available in the Mesh Output dialog shown in Figure 5 1 This dialog is called up when you select Write Mesh File from the File menu The Format drop down on the Mesh Output dialog allows you to select between Tecplot and PLOT3D FAST file formats Two option buttons just below this menu allow you to specify ASCII or binary ASCII is recommended for PLOT3D files if you wish to move between dif ferent architectures Windows and UNIX or different UNIX platforms ASCII is also recom mended for the Tecplot file format since software reading the mesh may not be able to read binary Tecplot files 65 Chapter 5 Exporting Meshes Hesh Output x Format Tecplot ff ASCII Binary Mesh Conversion f Mone Single Triangular Zone C Single Quadrilateral Zone o Unstructured surface 8 OK Cancel Help Figure 5 1 The Mesh Output dialog 5 1 1 The Tecplot Format The Tecplot mesh file format is a standard Tecplot data file augmented with boundary informa tion including inter mesh connections As such it may be read directly into Tecplot for view ing Refer to the Tecplot User s Manual for details on this file format Binary Tecplot mesh files are written in double precision Boundary information is contained in USERREC fields described below These fields are used to describe boundary regions on both structured and unstructured meshes Connections between meshes are identified by
19. Generator dialog to the side of the screen to avoid obstructing the Tecplot workspace Chapter 1 Getting Started To end a session in Mesh Generator simply exit Tecplot You may close Mesh Generator s main dialog by clicking Close on the lower left hand side of the dialog Selecting Mesh Gener ator from the Tools menu on the Tecplot menu bar will call it up again 1 1 2 Starting and Stopping on Windows Systems On Windows 95 98 and NT 4 0 you should first start Tecplot From the Tecplot menu bar select Tools then select Mesh Generator from the menu The Mesh Generator main dialog will appear Mesh Generator is now running To end a session in Mesh Generator simply exit Tecplot You may close Mesh Generator s main dialog by clicking Close on the lower left hand side of the dialog Selecting Mesh Gener ator from the Tools menu on the Tecplot menu bar will call it up again 1 2 Getting Acquainted with Mesh Generator Mesh Generator s main dialog is shown in Figure 1 1 The Mesh Generator main dialog is divided up into three menus and a check box e File You may import IGES Initial Graphics Exchange Specification files containing NURB Non Uniform Rational B splines curve entities read or write a Mesh Generator project file or output generated meshes to an external file A project file is a Tecplot layout file with Mesh Generator macro commands embedded in it You can write a project file to save the current state
20. JMin text field Hyperbolic meshes are created with the Hyperbolic Structured dialog shown in Figure 3 3 The dialog is called up by choosing Create Hyperbolic Structured from the Mesh menu 51 Chapter 3 Creating Structured Meshes Hyperbolic Structured Boundaries Enter Mesh Boundary zone Numbers Jilin Add Fram List Mesh Control Layers JMax 25 Initial Spacing Total Distante Constraints thin None Max None lax Smoothing Passes 100 Reverse Marching Direction Mesh Label Create Relate Remove d Layer Close Help Figure 3 3 The Hyperbolic Structured dialog 3 2 2 Hyperbolic Mesh Control The Layers JMax text field on the Hyperbolic Structured dialog indicates the total number of mesh lines in the J direction the marching direction including the JMin boundary The Initial Spacing text field indicates the spacing between the JMin boundary and the first gener ated mesh line Total Distance is the approximate normal distance between the JMin boundary and the last added mesh line JMax boundary Both of these must be positive numbers and the value for Total Distance must be greater than that in Initial Spacing At the IMin and Max limits of the hyperbolic zone you may impose one of the following boundary constraints e None These boundaries evolve as the mesh is marched 52 3 2 Creating Hyperbolic Meshes e X Constant The boundar
21. Mesh Generator COMMAND CREATECONICARC XSTART YSTART XEND YEND XVERTEX 0 5 YVERTEX 1 0 LENGTHRATIO 0 5 NUMBEROFNODES 25 O OOO 0 0 oF Il Add a 50 node hyperbolic LENGTHRATIO gt 0 5 arc with multiple hyperbolic tangent distribution one clustering point ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATECONICARC XSTART 5 0 YSTART 3 0 XEND 3 0 81 Chapter 6 Extended Macros Syntax ADDONCOMMAND ADDONID YEND 5 0 XVERTEX YVERTEX LENGTHRATIO 0 75 DISTRIBUTION MULTIPLETANH NUMBEROFNODES 50 INITIALSPACING 01 FINALSPACING 01 RAWDATA 2 1 4 0 7 0 4 0 7 0 001 26 EXTRACTLINE Mesh Generator COMMAND EXTRACTLINE optional parameters Description Create a new mesh line whose nodes are a subset of an existing line or surface Optional Parameters Parameter Syntax REPLACEZONE lt integer gt LABEL lt string gt SOURCEZONE lt integer gt BOUNDARYLINE lt zoneboundary gt Default Notes 0 Zone to replace with the extracted line If 0 a new line is created E The zone title to apply to the created line 1 The zone number of the source zone IMIN Ignored if the source zone is a line If the source zone is a surface an IJ ordered zone this parameter indicates from which zone boundary the line is to be extracted 82 Macro Commands Parameter Syntax Defaul
22. NURB curve If MULTIPLETANH distribution is used the clustering data must be specified in the RAWDATA section See 6 5 Raw Data on page 95 for a description of lt clusteringrawdata gt Required Parameter Parameter Syntax Notes REPLACEZONE lt integer gt Zone to replace with the generated line Optional Parameters Parameter Syntax Default Notes LABEL lt string gt un The zone title to apply to the line DISTRIBUTION EVENS PACING The method used to distribute points along lt distributionoption gt the path defined by the NURB curve If MULTIPLETANH then the RAWDATA sec tion must contain clustering data The ASIS option is not available NUMBEROFNODES lt integer gt 30 The number of mesh nodes to distribute along the curve REVERSELINEDIRECTION FALSE If set to TRUE the mesh nodes are distrib lt boolean gt uted in the opposite direction of the curve TWOSIDED lt boolean gt TRUE Not used for ASIS and EVENSPACING distribution options If FALSE only the ini tial or final node spacing is used set the other to zero If TRUE both initial and final spacing are set 84 Macro Commands Parameter Syntax Default Notes INITIALSPACING 001 The initial node spacing lt double gt FINALSPACING lt double gt 001 The final node spacing Used only if TWO SIDED is set to TRUE Example Edita line to give it 25 nodes with default even spacing distribution ADDONCOMMAND AD
23. Nodes to 30 and accept all other default values Click OK 3 Use the Line Label text field on the Polyline dialog to name this boundary line b4 Click Create Close the Polyline dialog 4 From the Tecplot menu bar select the View menu then select the Data Fit option to display all of the newly created boundary line 1 3 2 4 Creating the JMax Boundary To create the JMax boundary the JMax starting node JMax must be coincident with Min max Also the JMax max and Max max must be coincident Finally JMax must have 59 nodes the same number as b1 and b2 though both 1 3 Creating Simple Meshes boundaries have 30 nodes they lose one at the overlapping node the JMin boundary Perform the following steps 1 Call up the Create Circular Arc dialog under the Boundary menu First set the Specify option button to Starting Ending Point Radius Use of the Selector tool method to insert IMin s start point of 5 0 as JMax s start point and Max s end point of 5 6 as JMax s end point Set the Radius text field to 10 2 Click Node Distribution On the Node Distribution dialog set Number Of Nodes to 59 All other default values are correct for our arc Click OK 3 Use the Line Label text field on the Circular Arc dialog to name the JMax boundary b5 Click Create Close the dialog The resulting boundaries are shown in Figure 1 5
24. Parameter Assignment Values Parameter assignments referenced in the previous section using angle brackets lt gt s and not defined in the Tecplot Reference Manual are defined here Note that case is not impor tant Value Identifier lt distributionoption gt lt interpolationoption gt lt circlespec gt lt zoneboundary gt lt ellipticmethod gt lt list gt lt constraint gt lt gridformatoption gt lt gridtypeoption gt lt conversionoption gt Allowable Values ASIS EVENSPACING EXPONENTIAL TANH MULTIPLETANH POLYNOMIAL CUBIC LINEAR SPECIFYORIGIN SPECIFYRADIUS IMIN IMAX JMIN JMAX ALGEBRAICARCLENTH ALGEBRAICLINEAR ALGEBRAICEDGEORTHO ELLIPTICLAPLACE ELLIPTICTHOMAS ELLIPTICORTHOGONAL lt integer gt lt integer gt NONE XCONSTANT YCONSTANT PERIODIC TECPLOT PLOT3D ASCII BINARY NONE TRIANGULAR QUADRILATERAL 94 Raw Data 6 5 Raw Data Some macro commands contain a raw data section A raw data section is defined by using the keyword RAWDATA followed by the raw data values unique to the macro command Most raw data sections start with a single count value which represents the number of blocks of raw data followed by the blocks of raw data themselves The following table lists the raw data sections found in Mesh Generator macros Value Type s Raw Data Name per Block Notes lt polylinerawdata gt lt xyrawdata gt The first block contains the loc
25. and b4 as the JMin boundary Note that because the b6 boundary has the lower I index values you must list it before b4 3 Click in the Reverse Marching Direction check box so that the new mesh will not overlay the existing mesh 4 Accept the other default values then use the Mesh Label text field to name the new mesh connected then click Create The Working dialog will appear while the new mesh is gen erated 5 From the Tecplot menu bar select the View menu then select the Data Fit option to display all of the newly created boundary line The resulting mesh is shown in Figure 3 6 A S N D TRS CRS N j LL EEL G SEE OF DUR sec cecseccrasesareaesarescetesuseresesurcauietasetatted E UA 5 0 5 X Figure 3 6 The connected Hyperbolic Structured mesh 57 Chapter 3 Creating Structured Meshes 58 cHapTeR4 Creating Unstructured Meshes In Mesh Generator an unstructured mesh is formed by filling a boundary enclosed area with triangular mesh cells One outer boundary must be specified to enclose the mesh while an arbitrary number of inner boundaries may be specified to cut out portions of the mesh Inner boundaries generally represent geometries such as an airfoil in a flow field 4 1 Selecting Closed Loop Boundaries Unstructured meshes are created by clicking on the Mesh menu then selecting Create Unstruc tured The Unstructured dialog is
26. as the JMin boundary for the flap In the Mesh Control area set Layers JMax to 15 Initial Spacing to 0 00054 Total Dis tance to 0 02 and Max Smoothing Passes to 25 On the Hyperbolic Structured dialog accept all other default values and use the Mesh Label text field to name this mesh f2 Click OK After it has been created close the Hyperbolic Structured dialog 113 Chapter 7 Examples 7 4 4 Extractng to Create Internal Boundaries The IMin Max and JMax lines of our mixing area boundaries s2 w2 and f2 will now be extracted and combined with the JMax lines of the hyperbolic meshes around each element f1 wl and f1 on the slat wing and flap to form internal boundaries for the unstructured mesh To create these boundaries perform the following steps 1 Using the Tecplot Selector tool select s2 in your current Tecplot frame Under the Bound ary menu choose Extract From Selected Mesh This will call up the Extract Selected Mesh dialog On the Extract Selected Mesh dialog accept all default values and use the Line Label text field to name this sa Click OK Using the Tecplot Selector tool select s2 again On the Extract Selected Mesh dialog set Boundary Line to JMax Line Accept all other default values then use the Line Label text field to name this sb Click OK Select s2 again On the Extract Selected Mesh dialog set Boundary Line to Max Line Accept all other default values t
27. associating two of these regions Each boundary line used to create a zone becomes a boundary region in the mesh file For example if two such lines form the JMin boundary for a hyperbolic mesh then two boundary regions will be output for the JMin face of that mesh one corresponding to each boundary line Each boundary region is assigned the same label as the corresponding boundary which is also the Tecplot zone name for that boundary 66 5 1 Selecting the Format If a particular boundary line was used in the boundaries of two meshes or if a boundary line was extracted from one mesh and used in the boundary of another then those two meshes are considered connected together This information is also placed in the mesh file see Section 5 1 1 4 IZPLABEL for further details 5 1 1 1 The Tecplot USERREC Tecplot allows arbitrary character information to be embedded in data files In ASCII data files this information is enclosed in quotation marks and identified with the USERREC keyword USERREC This is arbitrary information These USERREC fields are used to hold all boundary information in Tecplot ASCII and binary mesh files 5 1 1 2 SBPATCH The SBPATCH USERREC field describes a boundary patch on a struc tured mesh It includes the zone number a label the zone face I Min IMax and so on and the first and last nodes of the patch In an ASCII Tecplot file it would look like USERREC SBPATCH 3 Wall 2 1 6
28. dialog Once you have defined the boundaries for a mesh you may select any of the three algebraic methods to generate a structured mesh 3 1 2 Algebraic Mesh Control There are six mesh control methods in the Mesh Control section of the Algebraic Elliptic Structured dialog These are Algebraic Arclength Algebraic Linear Algebraic Edge Ortho Elliptic Laplace Elliptic Thomas and Elliptic Orthogonal The first three mesh control methods are algebraic meshes These are e Algebraic Arclength Mesh nodes are interpolated using arc length distances from the boundary nodes This generally yields a better mesh than the other two options particularly when the boundaries have curvature Therefore it is used as the default 47 Chapter 3 Creating Structured Meshes e Algebraic Linear This uses standard linear interpolants for transfinite interpolation which usually results in satisfactory meshes However mesh lines may cross when using this method on highly curved boundaries e Algebraic Edge Ortho This uses a blending function similar to Algebraic Arclengh with additional constraints added to make the mesh orthogonal at the boundaries When an algebraic mesh control option is selected all other mesh control parameters are inac tive 3 1 3 Labeling an Algebraic Structured Mesh A name can be assigned to each mesh you create The Mesh Label text field is located at the bottom of the Algebraic Elliptic Structured dialo
29. dialog must be entered in units consistent with the physical coordinates The default values are set to 0 001 2 7 3 1 Multiple Tanh The Multiple Tanh area of the Node Distribution dialog is active only when Distribution is set to Multiple Tanh This area contains a list of cluster control points text fields for entering these points and buttons for controlling the points The cluster ing control point list is used to control the clustering information Initially this list will be empty In addition to the Initial and Final Spacing values you must specify at least one addi tional clustering control point by entering the values in the four Multiple Tanh text fields X Y Spacing and Nodes The clustering points may be entered in any order and are sorted by dis tance along the line starting from the first control point Figure 2 11 illustrates a line defined by five control points and Interpolation set to Cubic This demonstrates how the cluster points divide the line into sections The sorting places the cluster points on the line in the order 1 3 2 to create four line sections though the order in which the points would appear in the list is 1 2 3 For the purpose of defin ing the sections the starting and ending points on the line are considered to be clustering points The values for X and Y are the approximate coordinates along the boundary line at which the clustering is to be focused The actual coordinates will be calculate
30. do this by entering a Start index value greater than that of the End index value This in effect reverses the line direction for your newly extracted boundary line The extracted nodes will be the same but the index order will proceed in the opposite direction along the line 34 2 6 Extracting New Boundaries 2 6 2 Labeling the Boundary A name can be assigned to each boundary you create This simplifies boundary selection when choosing from a list to create your mesh You may enter any characters you wish in the Line Label text field 2 6 3 Creating the Boundary The new boundary will be created and displayed in the current Tecplot frame after you click Create It will be a Tecplot I ordered zone 2 6 4 Extracting from a Selected Mesh This option is activated by selecting a mesh IJ ordered zone to be used for extracting the new boundary On the Boundary menu select Extract From Selected Mesh This will call up the Extract Selected Mesh dialog shown in Figure 2 10 Extract Selected Mesh x Line Definition Boundary Line fimin line otart End Index 0 Line Label othogonal OK Cancel Help Figure 2 10 The Extract Selected Mesh dialog 35 Chapter 2 Creating Boundaries In the Line Definition area of the dialog you must enter the starting and ending indices and the specific boundary of the mesh from which you want to extract the new boundary The indices are entered into the St
31. edited until an acceptable smoothing factor is determined 104 7 2 Three Element Airfoil Example with a Hyperbolic Structured Mesh 10 14 15 ee 16 5 15 13 9 8 7 12 1 11 2 3 14 Figure 7 5 Clockwise entry of zone numbers beginning at the lower edge of the flap 3 In the Mesh Control area of the Hyperbolic Structured dialog set Layers JMax to 10 Total Distance to 0 1 Constraints to Periodic setting the Min or Max drop down to Peri odic will automatically set the other to Periodic and Max Smoothing Passes to 1000 Accept all other default values then use the Line Label text field to name this boundary mesh1 Click Create The Working dialog will appear while the mesh is generated 7 2 3 Editing the Hyperbolic Mesh After a mesh is created it should be closely examined Each mesh cell should be distinct and no mesh folding or overlapping should be present Close inspection of the outermost row of cells in the region below bc1 reveals that these cells are overlapping In this case the mesh should be modified before proceeding To edit the mesh perform the following steps 1 First select the mesh using the Tecplot Selector tool by clicking on a node on the mesh Now choose Edit Selected Mes
32. from the command line when you launch Tecplot using the p option 6 1 The ADDONCOMMAND Tecplot Macro All of Mesh Generator s macro commands are embedded within Tecplot s ADDONCOMMAND macro The syntax of this macro is shown below ADDONCOMMAND ADDONID lt string gt COMMAND lt string gt RAWDATA lt string gt 73 Chapter 6 Extended Macros lt string gt The first lt string gt is a text string identifying the Tecplot add on which should receive the command For Mesh Generator this should be set to Mesh Generator The second string is sent to the add on and contains all information the add on needs to process the command The square brackets around RAWDATA indicate that a RAWDATA section may be included with ADDONCOMMANDS Some of Mesh Generator s macros make use of this feature 6 2 Macro Command Summary Mesh Generator has 16 macro commands which may be embedded in the ADDONCOMMAND macro as noted above These are CREATEPOLYLINE Creates a new boundary line from a set of points CREATECIRCULARARC Creates a new boundary line along a circular arc CREATECONICARC Creates a new boundary line along a conic arc EXTRACTLINE Copies points from an existing boundary line or mesh zone to form a new line CREATELINESFROMNURBFILE Reads an IGES file and creates boundary lines from any NURB curves it finds in the file EDITLINEFROMNURBCURVE Allows the node distribution options to be set f
33. meshes Algebraic Elliptic and Hyperbolic Algebraic methods used in Mesh Generator are based on transfinite interpolation TFI These are very fast and usually generate meshes directly acceptable for calculations Elliptic methods used in Mesh Generator are based on iterative solution of Poisson s equation They are often used to improve on the quality the orthogonality and to smooth minor irregu larities of algebraic meshes The Hyperbolic method used in Mesh Generator is based on the advancing front method fol lowed by an elliptic smoothing This method sequentially marches along a set of mesh lines Elliptic smoothing is only used to smooth and relax any irregularity on each step This is a very fast and robust method for generating external meshes As a special output option the resulting structured meshes may be converted into a single quadrilateral or triangular unstructured mesh You may choose to use different mesh generation methods in different zones 3 1 Creating Algebraic or Elliptic Meshes Algebraic and elliptic meshes are defined by selecting the boundary lines that form the four boundaries Min IMax JMin and JMax of a mesh zone block A hyperbolic mesh is defined by selecting boundary lines which form the JMin boundary 45 Chapter 3 Creating Structured Meshes 3 1 1 Specifying Boundaries Algebraic and elliptic structured mesh generation requires that all four boundaries I Min IMax JMin
34. name this linel then click Create Repeat the process described above to create an element extension from the trailing edge of the wing and from the trailing edge of the flap using the same settings on the Node Distribution dialog and labeling them line2 and line3 respectively 7 3 2 Creating the Hyperbolic Meshes We will now create the hyperbolic mesh for our example To do this perform the following Steps 1 2 From the Mesh Generator menu select Create Hyperbolic Structured on the Mesh menu This will call up the Hyperbolic Structured dialog We will be using the zone numbers of the slat as well as its newly created extension as our JMin boundary You may enter these values either by typing them in manually clicking the Add From List buttons or using the Tecplot Selector tool in conjunction with the Add Selected buttons Add From List will read Add Selected when using the Selector tool 107 Chapter 7 Examples You should enter the zones in clockwise order starting at the trailing edge of the flap the beginning of zone 14 The order of all the zones as entered clockwise is 14 1 2 3 4 and 14 In the Mesh Control area of the Hyperbolic Structured dialog set Total Distance to 0 006 Accept all other default values then use the Mesh Label text field to name this boundary m1 Click Create The Working dialog will appear while the mesh is generated Repeat the process describ
35. number If the Node Distribution option is set to As Is the only valid entry for Number Of Nodes is that equal to the number of Control Points listed Line Definition 2 7 2 1 Line Direction Reverse Line Direction The Reverse Line Direction check box enables you to switch the direction of the node index order along a boundary when it is created It has no effect on the node distribution The default direction of the node index order is from starting to ending point of a line accord ing to the order of the Control Points in the Line Definition area of the Polyline dialog Revers ing the line direction does not affect how the nodes are distributed as it is based upon the line direction defined by your control points Instead reversing the line direction occurs after the nodes have been distributed along the created boundary 38 2 7 Distributing Nodes Along the Boundaries 2 7 3 Node Spacing For the Exponential Tanh Multiple Tanh and Polynomial Distribution options you are required to enter values for the Initial and Final Spacing For the One Sided options only the Initial or Final Spacing is required Spacing is the distance between two adjacent nodes Initial Spacing is the spacing at the first node index and Final Spacing is the spacing next to the last node The spacing between the nodes depends upon your distribution option The values you enter in the Initial and Final Spacing text fields on the Node Distribution
36. q The numbers of zones that form the boundary IMAXBOUNDARY lt list gt q The numbers of zones that form the Max boundary 87 Chapter 6 Extended Macros Parameter Syntax Default Notes JMINBOUNDARY lt list gt ngn The numbers of zones that form the J 1 boundary JMAXBOUNDARY lt list gt ngn The numbers of zones that form the J JMax boundary ORTHORELAXATION 0 1 For the elliptic orthogonal method only the lt double gt normalized distance as a percentage of I or J index at which the orthogonality con straint is relaxed to ten percent of its maxi mum MAXITERATIONS lt integer gt 100 For elliptic methods only the maximum number of relaxation iterations to perform RELAXATION 1 For elliptic methods only the relaxation lt double gt factor for the rexation method Example Create an elliptic surface using the Laplace method with no more than 20 iterations ADDONCOMMAND ADDONID COMMAND CREATEELLIPTICSURFACE LABEL Surface 1 IMinBoundary 3 Mesh Generator IMaxBoundary 4 JMinBoundary 1 JMaxBoundary 2 Method EllipticLaplace MaxIterations 20 CREATEHY PERBOLICSURFACE Syntax ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATEHYPERBOLICSURFACE optional parameters Description Create a new hyperbolic surface 88 Macro Commands Optional Parameters Parameter Syntax REPLACEZONE lt integer gt LABE
37. selected in the current Tecplot frame The Select Endpt buttons allow you to automatically enter the coordinates of the end point closest to a node selected with the Tecplot Selector tool This allows an exact specification of a given end point without having to manually enter the values It avoids mismatch errors which can create problems when attempting to combine the multiple boundaries of a mesh 2 2 1 2 Converting Circle Geometries into Boundaries To the right of the Counter Clockwise check box is the Convert Circle Geometry button This is active only when a Tecplot circle geometry is selected in the current frame By clicking on this button the selected circle geometry is converted into a circular arc of 360 degrees This allows you to draw a circle with the Tecplot circle drawing tool and directly convert it into a boundary in Mesh Generator Note After clicking Convert Circle Geometry the selected circle geometry is deleted from the current Tecplot frame 24 2 3 Conic Arcs 2 2 2 Node Distribution The number of nodes the distribution option and the interpolation on a circular arc is set by clicking Node Distribution When you click Node Distribution the Node Distribution dialog will be called up This is discussed in Section 2 7 Distributing Nodes Along Boundaries The default Distribution is Even Spacing and default Number Of Nodes is 30 2 2 3 Labeling a Circular Arc Boundary A name can be assigned to
38. text field to name this boundary jmin1 then click Create Close the dialog 7 1 2 Creating an Algebraic Mesh With our boundary properly defined we will now create a structured mesh for our flat plate example To create this mesh perform the following steps 1 From the Mesh menu select Create Algebraic Elliptic Structured This will call up the Algebraic Elliptic Structured dialog In the Boundaries area of the Algebraic Elliptic Structured dialog you must enter the boundary line into the Enter Mesh Boundary Zone Numbers text fields You may do this by entering the values manually clicking Add From List buttons or using the Tecplot Selector tool in conjunction with Add Selected buttons The Add From List buttons will read Add Selected when using the Selector tool You should define Min as imin1 and imin2 Max as imax and imax2 JMin as jmin1 and JMax as jmax1 Accept all other default values When you do not specify a label Mesh Generator will assign a name based on the type of mesh being used and its zone number for example Structured surface 7 Click Create then close the dialog The resulting mesh is shown in Figure 7 2 After a mesh is created it should be closely examined paying special attention to regions bounding surfaces and other areas of interest For the flat plate example it is desirable that the radial lines of the mesh extend very close to perpendicular from the surface Close examination of
39. the Algebraic Arclength mesh reveals that this has not been achieved Thus we can now delete the surface or edit it 100 7 1 Two Dimensional Flat Plate Example with a Structured Mesh 0 0002 0 00015 0 0001 gt l 5E 05 0 0 0001 0 0 0001 X Figure 7 2 The Algebraic Arclength mesh 7 1 3 Editing to Create an Elliptic Mesh Editing is very time efficient if the boundaries being used are not modified We will now edit the mesh in our flat plate example To do this perform the following steps 1 First select the mesh using the Tecplot Selector tool by clicking on a node on the mesh Now choose Edit Selected Mesh from the Mesh menu This will call up the Algebraic Elliptic Structured dialog 2 On the Algebraic Elliptic Structured dialog set Mesh Control Method to Elliptic Thomas and Maximum Iterations to 200 Accept all other default values and click Replace The Working dialog will appear while the mesh is regenerated The resulting mesh is shown in Figure 7 3 The mesh should be carefully examined again At the surface you will see that the radial lines now extend nearly perpendicular and the overall mesh looks smooth without obvious distor tions 101 Chapter 7 Examples 0 0002 0 00015 0 0001 gt 5E 05 0 0001 0 0001 xo Figure 7 3 The Elliptic Thomas mesh 7 2 Three Element A
40. then click on the Boundary menu selecting the Delete Selected Line option 2 Now repeat step 9 to delete boundary b5 28 2 4 Importing Boundary Files 3 To create a replacement for b3 click on the Boundary menu and select Create Polyline On the Polyline dialog enter the coordinates 0 for X and O for Y and click Insert Before Now enter the coordinates 2 for X and 0 for Y and click Insert After 4 Now click Node Distribution On the Node Distribution dialog set Distribution to Even Spacing and Number Of Nodes to 30 Accept all other default settings and click OK 5 On the Polyline dialog use the Line Label text field to name this boundary b3 and click Create 6 To replace boundary b5 we want to create a conic arc shaped like an ellipse 7 Use the Tecplot Selector tool select a node on b3 near its end point Now click on the Boundary menu and select Create Conic Arc This will call up the Conic Arc dialog On the dialog click Select Endpt across from the Start text fields Use the Tecplot Selector tool to click on a node near the end of b4 On the Conic Arc dialog click Select Endpt across from the End text fields Now enter the coordinates 2 6 for Vertex then set the Length Ratio to 0 4 8 Click Node Distribution On the Node Distribution dialog set Distribution to Even Spacing and Number Of Nodes to 30 Click OK 9 On the Conic Arc dialog use the Line Label text field to name this boundary b5
41. with the Tecplot Selector tool On the Polyline dialog click Select Endpt to enter the X and Y values into the text fields then click Insert Before to add the values to the Control Points list Now manually enter the X and Y coordinates for the end points of the downstream boundary using 9 5e 5 for X and 2 0225e 4 for Y Click Insert After Click Node Distribution on the Polyline dialog On the Node Distribution dialog set Distri bution to Exponential Number of Nodes to 23 Spacing to Two Sided Initial Spacing to le 7 Final Spacing to le 5 Click OK On the Polyline dialog use the Line Label text field to name this boundary jmax1 then click Create Close the dialog We will now create the first section of the farfield or IMax boundary 1 From the Boundary menu select Create Circular Arc On the Circular Arc dialog set Spec ify to Center Starting Point Arc Angle Center to 1 le 4 for X and 1 6e 6 for Y Start to 7 5e 5 for X and O for Y and Arc Angle to 51 Click Node Distribution On the Node Distribution dialog set Distribution to Exponential Number of Nodes to 11 Spacing to Two Sided Initial Spacing to 1 3e 5 Final Spacing to 2 0e 5 Click OK On the Circular Arc dialog use the Line Label text field to name this boundary imax1 then click Create Now we will create the second section of the farfield or IMax boundary 1 First click on the end node or a node near the end of imax1 with th
42. 23 Chapter 2 Creating Boundaries 2 2 1 Line Definition The Line Definition area of the Circular Arc dialog allows you to create circular arcs using one of three different methods 2 2 1 1 Specifying Circular Arcs Two options are available by clicking on the option buttons under Specify in the Line Definition area of the Circular Arc dialog These are e Center Starting Point Arc Angle Specifies the center origin the starting point on the circumference of a circle and the arc angle of a circle e Starting Ending Point Radius Specifies both the starting and ending points on the cir cumference of a circle with a specified radius The default direction of circular arcs in Mesh Generator is clockwise You may reverse the direction by clicking on the Counter Clockwise check box Note In instances where two solutions are possible the smaller arc will always be selected Depending upon which option is selected under Specify the text fields in the Arc area of the Circular Arc dialog will be active or inactive The X and Y coordinates for the appropriate points may be manually entered into the text fields labeled X and Y You must enter a value in units of degrees in the Arc Angle text field The value entered in the Radius text field must have units consistent with the X and Y coordinates Next to the X and Y text fields for Start and End are two Select Endpt buttons which are active only when another boundary line is
43. 38 Reverse Marching Direction 53 Reversing line direction 38 on Extract From Selected Line dialog 34 S Save Project 16 Saving files 15 meshes 65 SBPATCH boundary patches 67 Select Endpt button 20 Selected Line Info option 42 Single quadrilateral mesh 70 Single triangular mesh 71 Specify on Circular Arc dialog 24 Start text field 22 on Conic Arc dialog 25 on Extract From Selected Line dialog 34 on Extract Selected Mesh dialog 36 Start text field on Circular Arc dialog 24 Starting Ending Point Radius 24 Structure meshes editing 105 Structured meshes Algebraic 45 control 101 creating Hyperbolic Structured 102 creation 100 editing 101 Elliptic 45 Hyperbolic 45 51 patches 67 Syntax for Hygrid macro commands 75 7 Tanh distribution 37 Technical Support 17 Tecplot data 29 Tecplot data file 66 Tecplot File menu 29 Macro Files 17 Tecplot Load DataFile s option 29 Tecplot mesh file format 66 Tecplot Tools menu 1 2 Total Distance on Hyperbolic Structured dialog 52 U Unix closing Mesh Generator 2 loading Mesh Generator 1 Unstructured creating 115 editing 110 Unstructured dialog 59 adding boundary lines 59 Closed Loop Boundaries area 59 Create button 61 Delete button 61 external boundaries 60 internal boundaries 60 Maximum Cells 61 Mesh Boundary Zone Numbers list 59 mesh control 61 Mesh Label 61 Mesh Smoothing 61 New Boundary button 59 Reverse Direction 61 Unstructured mesh control 61 Unstructured meshe
44. 8 Algebraic Elliptic 4 Algebraic Linear mesh control 48 boundaries for structured 46 boundary constraints in Hyperbolic Structured meshes 52 boundary extraction in Hyperbolic Structured 114 bounding edges in Algebraic Elliptic 4 closed loop boundaries in Unstructured meshes 59 C Mesh 111 coincident mesh points 4 connection 102 Connectivity 55 control 52 101 conversion 14 69 converting to single quadrilateral 70 converting to single triangular 71 creating 51 creating Algebraic Elliptic Structured 10 creating hybrid meshes 106 creating Hyperbolic Structured 51 102 111 113 creating structured 45 creating Unstructured 115 creating Unstructured meshes 62 creation 45 100 defining types 45 Delete Selected Mesh 3 deleting 3 55 62 editing 61 101 105 editing Unstructured 61 110 element extensions 106 Elliptic mesh control 47 48 Elliptic mesh creation 45 Elliptic Relaxation 49 Elliptic Laplace 48 Elliptic Orthogonal mesh control 49 Elliptic Thomas mesh control 48 examples 97 exporting 65 extracting boundaries 108 Extracting from a selected mesh 35 file format 66 Hybrid 1 hybrid 106 Hyperbolic 4 45 51 Hyperbolic Structured 102 Hyperbolic Structured in hybrids 107 Max Smoothing Passes 53 maximum iterations 49 mesh control paramaters 48 methods of creating 45 Modfied 111 modifying 11 13 Orthogonality Relaxation 49 patches on structured meshes 67 Reverse Direction on Unstructure
45. CREATEUNSTRUCTUREDSURFACE MAXCELLS 10000 RAWDATA WF N A N U1 P REMOVELAYER Syntax ADDONCOMMAND ADDONID Mesh Generator COMMAND REMOVELAYER lt integer gt no parameters Description Remove the J JMax line from the indicated zone Example Remove the J JMax line from zone 3 ADDONCOMMAND ADDONID Mesh Generator COMMAND REMOVELAYER 3 DELETEZONE Syntax ADDONCOMMAND ADDONID Mesh Generator COMMAND DELETEZONE lt integer gt no parameters Description Delete the indicated Tecplot zone unless another zone is dependent on it Example Delete zone 3 ADDONCOMMAND ADDONID Mesh Generator COMMAND DELETEZONE 3 91 Chapter 6 Extended Macros READPROJECTFILE Syntax ADDONCOMMAND ADDONID Mesh Generator COMMAND READPROJECTFILE lt string gt no parameters Description Clear the existing mesh generation project and read the project file indicated by lt string gt Example Read project file airfoil lay ADDONCOMMAND ADDONID Mesh Generator COMMAND READPROJECTFILE airfoil lay WRITEPROJECTFILE Syntax ADDONCOMMAND ADDONID Mesh Generator COMMAND WRITEPROJECTFILE lt string gt no parameters Description Save the existing mesh generation project to the file indicated by lt string gt Example Write project file airfoil lay ADDONCOMMAND ADDONID
46. Circular Arcs 23 default direction 24 default node distribution 25 editing 41 information 42 Node distribution 37 Closed loop boundaries direction 60 Closed Loop Boundaries area on Unstructured dialog 59 Clustering control points in Multiple Tanh distribution 38 C Meshes 111 Conic Arc dialog 25 Create button 27 End 25 Length Ratio 26 Line Definition area 25 Line Label 27 Node Distribution button 27 Start 25 Vertex 25 Conic Arcs 25 default node distribution 27 editing 41 information 42 Node distribution 37 Connectivity 55 Control points polylines 19 to define boundary shape 19 Control Points list 5 entering data into 5 Convert Circle Geometry button 24 Convert Polyline Geometry Insert After button 21 Converting meshes 14 Converting circle geometries 24 Counter Clockwise option 24 Create button on Algebraic Elliptic Structured dialog 48 50 on Circular Arc dialog 25 on Conic Arc dialog 27 on Extract From Selected Line dialog 35 118 on Extract Selected Mesh dialog 36 on Hyperbolic Structured dialog 54 on Unstructured dialog 61 Create Circular Arc 5 Create Conic Arc 25 Create From Selected Line 31 Create Hyperbolic Structured 51 Create Hyperbolic Structured option 51 Create Polyline 5 Create Unstructured 59 CREATECIRCULARARC macro command 77 CREATECONICARC macro command 80 CREATEDEFAULTLINEFROMNURB macro command 86 CREATEELLIPTICSURFACE macro command 87 CREATEHYPERBOLICSURFAC
47. Converting polyline geometries 21 creating 97 creating from existing boundaries 30 creation 30 Delete Selected Line 3 deleting 42 direction of closed loops 60 Editing 41 editing permitted on extracted boundaries 36 examples 97 117 Index External 60 Extracting from a selected mesh 35 Extracting from an existing line 33 extracting from Hyperbolic Structured 112 extracting in Hyperbolic Structured 114 extracting new boundaries 33 extraction 108 for structured meshes 46 Max line option on Extract Selected Mesh dialog 36 Max orientation 7 Min line option on Extract Selected Mesh dialog 36 Min orientation 6 importing boundary files 29 in bounding edges 4 in Hyperbolic Structured meshes 51 in Unstructured meshes 60 information 42 Internal 60 introduction 19 JMax line option on Extract Selected Mesh dialog 36 JMax orientation 8 JMin 5 JMin line option on Extract Selected Mesh dialog 36 modifying 11 12 Node distribution 37 patches 67 polylines 19 shape defined by control points 19 used in structured meshes 46 USERREC fields 66 Boundary menu 2 19 C Center Starting Point Arc Angle 24 Circular Arc Arc Angle 24 Circular Arc dialog 5 23 Arc area 24 Center Starting Point Arc Angle 24 Convert Circle Geometry button 24 Create button 25 End 24 Line Definition area 24 Line Label 25 Node Distribution button 25 Radius 24 Specify 24 Start 24 Starting Ending Point Radius 24
48. DONID Mesh Generator COMMAND EDITLINEFROMNURBCURVE REPLACEZONE 2 NUMBEROFNODES 25 Example 2 Edita line to give it 50 nodes with multiple hyperbolic tangent distribution three clustering points Reverse the line direction ADDONCOMMAND ADDONID Mesh Generator COMMAND EDITLINEFROMNURBCURVE REPLACEZONE 3 DISTRIBUTION MULTIPLETANH NUMBEROFNODES 50 REVERSELINEDIRECTION TRUE INITIALSPACING 01 FINALSPACING 0O1 RAWDATA WW Pe PW D uO U A A W INO Ul 001 16 a eae tf 001 11 85 Chapter 6 Extended Macros Syntax Description Example Syntax Description Syntax Description CREATELINESFROMNURBFILE ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATELINESFROMNURBFILE lt string gt Create mesh lines from IGES NURB curves in a file The string must contain one file name which should be a valid IGES ASCII file Create mesh lines from file airfoil igs ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATELINESFROMNURBFILE airfoil igs r READNURBFILE ADDONCOMMAND ADDONID Mesh Generator COMMAND READNURBFILE lt string gt Read an IGES file containing NURB curves This macro is intended only for use by Mesh Generator to write project files You should not use this macro in your macro files CREATEDEFAULTLINEFROMNURB ADDONCOMMAND ADDONID Mesh Generator COMMAND C
49. E macro command 88 CREATELINESFROMNURBEFILE macro command 83 86 CREATEPOLYLINE macro command 75 CREATEUNSTRUCTUREDSURFACE macro command 90 Creating boundaries from existing boundaries 30 D DBPATCH 67 Delete button 21 on Unstructured dialog 61 Delete Selected Line 3 Delete Selected Lines 42 Delete Selected Mesh 3 55 62 DELETEZONE macro command 91 Deleting meshes 55 62 Tecplot Delete Zone option 3 Dialogs Algebraic Elliptic Structured 46 Circular Arc 5 23 Conic Are 25 Control Points area on Polyline 20 Extract From Selected Line 33 Extract Selected Mesh 35 Help button 17 Hyperbolic Structured 51 Line Defintion area on Polyline 20 Line Info 42 main 2 Mesh Output 14 65 Node Distribution 6 37 Polyline 5 19 Read IGES File 30 Unstructured meshes 59 Direction of closed loop boundaries 60 E Edit Selected Mesh 55 Editing Boundaries 41 circular arcs 41 conic arcs 41 Hyperbolic Structured meshes 105 lines 41 meshes 55 61 101 NURB lines 41 polylines 41 structured meshes 101 EDITLINEFROMNURBCURVE macro command 84 Element extensions 106 Elliptic mesh definition 45 Elliptic meshes 45 boundaries 46 control 47 48 creation 45 Elliptic Relaxation 49 Elliptic Laplace 48 mesh control 48 Elliptic Orthogonal mesh control 49 Elliptic Thomas mesh control 48 End text field 22 on Conic Arc dialog 25 on Extract From Selected Line dialog 34 on Extract Selected Mesh dialog 36 End text field on Circular Arc dialog 24 Even Sp
50. Endpt This will enter the value for the ending node of the zone 4 boundary to the X and Y text fields Click Insert Before This will add the val ues to the Control Points list Using the Selector tool again click on a node on the leading edge of zone 10 Go back to the Polyline dialog and click Select Endpt then Insert Before The values will move to the top of the list 103 Chapter 7 Examples 3 Click Node Distribution On the Node Distribution dialog set Distribution to Exponential Number of Nodes to 15 Spacing to Two Sided Initial and Final Spacing to 5 0e 4 and accept all other default values Click OK On the Polyline dialog use the Line Label text field to name this boundary bcl then click Create Close the dialog Now we will add the branch connector from zone 10 to zone 13 Perform the following steps 1 Using the Tecplot Selector tool select a node near the trailing edge of zone 10 Now select Create Polyline from the Boundary menu this will call up the Polyline dialog On the Polyline Dialog click Select Endpt This will enter the value for the ending node of the zone 10 boundary to the X and Y text fields Click Insert Before This will add the val ues to the Control Points list Using the Selector tool again click on a node on the leading edge of zone 13 Go back to the Polyline dialog and click Select Endpt then Insert Before The values will move to the top of the list Click Node Distri
51. IN 3 0 XSTART 5 0 YSTART 3 0 ARCANGLE 45 0 NUMBEROFNODES 25 Example 2 Adda 50 node counter clockwise circular arc with multiple hyperbolic tangent distribution three clustering points specifying the starting and ending points and the radius ADDONCOMMAND Mesh Generator CREATECIRCULARARC ADDONID COMMAND SPECIFYORIGIN FALSE COUNTERCLOCKWISE TRUE XSTART 5 0 YSTART 3 0 XEND 3 0 YEND 5 0 RADIUS 5 5 DISTRIBUTION MULTIPLETANH NUMBEROFNODES 50 INITIALSPACING 01 FINALSPACING 01 RAWDATA 2 79 Chapter 6 Extended Macros WwW ARDAU uo u A A W INO Ul 001 16 sL rt 001 11 CREATECONICARC Syntax ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATECONICARC optional parameters RAWDATA lt clusteringrawdata gt Description Create a new mesh line whose nodes are distributed along a conic arc If MULTIPLETANH distribution is used the clustering data must be specified in the RAWDATA section See 6 5 Raw Data on page 95 for a description of lt clusteringrawdata gt Optional Parameters Parameter Syntax Default Notes REPLACEZONE lt integer gt 0 Zone to replace with the generated line If 0 anew line is created LABEL lt string gt ny The zone title to apply to the created line XSTART lt double gt Ta X location of the beginning of the arc YSTART lt double gt 0 0 Y location of the beginning
52. JMin boundary Call up the Polyline dialog by selecting the Create Polyline option from the Boundary menu The Polyline dialog is shown in Fig ure 1 3 4 On the left of this dialog is a list titled Control Points When you are first defining a new polyline boundary this list will be empty To the right of the Control Points list are two text fields labeled X and Y There are three ways to enter the control point values for your polyline by using Tecplot s Selector tool in conjunction with the Select Endpt button on the Polyline dialog by entering the values manually into the text fields and by converting a Tecplot geometry For this polyline we will use the first and second 5 With the Tecplot Selector tool click on b1 near one of its nodes closet to its end point of 1 1 On the Polyline dialog click Select Endpt This inserts b1 s end points into the X and Y text fields Click on Insert Before to enter the point into the list Now enter 5 for X and 1 for Y in the text fields Click Insert After Chapter 1 Getting Started Circular Arc x Line Definition Specify i Center Starting Point Arc Angle Staring Ending Point Radius D Counter Clockwise Convent Gihte Genmmetr AIC Center x 0 0 Start 1 0 Select Eno pt 0 select Emdpt End Radius Arc Angle E Degrees Mode Distribution Line Label Create Beplare Close Help Figure 1 2 The Circular Arc dial
53. L lt string gt BOUNDARY lt list gt NUMBEROFLAYERS lt integer gt INITIALSPACING lt double gt TOTALDISTANCE lt double gt IMINCONSTRAINT lt constraint gt IMAXCONSTRAINT lt constraint gt MAXLOCALITERS lt integer gt COLLISIONDETECTION lt boolean gt REVERSEDIRECTION lt boolean gt Default 0 WW WwW L 25 0001 NONE NONE 1000 FALSE FALSE Notes Zone to replace with the generated surface If 0 a new surface is created The zone title to apply to the created sur face The numbers of the zones which form the J 1 boundary The number of layers of the mesh includ ing the initial boundary JMax of the gener ated surface The normal distance between the initial boundary and second layer The approximate normal distance of the final layer from the initial boundary The constraint of the boundary The constraint of the Max boundary The maximum number of iterations per formed to smooth each layer If TRUE searches for collisions with other surfaces during generation If TRUE reverses the marching direction Example 1 Create a hyperbolic surface with periodic constraints making an O mesh ADDONCOMMAND ADDONID COMMAND Mesh Generator CREATEHYPERBOLICSURFACE BOUNDARY S123 TOTALDISTANCE 5 0 IMINCONSTRAINT PERIODIC IMAXCONSTRAINT PERIODIC Example 2 Create a hyperbolic surfa
54. LETEZONE 91 EDITLINEFROMNURBCURVE 84 EXTRACTLINE 82 READNURBFILE 86 READPROJECTFILE 92 REMOVELAYER 91 WRITEGRIDFILE 92 WRITEPROJECTFILE 92 Macro Files 17 Max Smoothing Passes 53 Maximum Cells 61 110 Maximum Iterations 49 Mesh editing 55 Mesh Boundary Zone Numbers list 59 Mesh connectivity 55 Mesh conversion 69 Mesh Output dialog 69 to single quadrilateral 70 to single triangular 71 Mesh generation Algebraic Elliptic 4 Hyperbolic 4 introduction 3 methods 4 Unstructured 4 Mesh Generator Boundary menu 2 Circular Arc dialog 23 Circular Arcs 23 closing 2 closing in Unix 2 Conic arcs 25 creating boundaries from existing boundaries 30 Creating conic arcs 25 examples 97 exporting meshes 65 Extracting new boundaries 33 File menu 2 loading 1 loading Unix 1 main dialog 2 mesh conversion 14 69 Mesh creation 45 Mesh menu 2 Meshes 45 modifying boundaries 11 modifying meshes 11 Node Distribution 37 Polyline dialog 19 Polylines 19 saving meshes 65 saving work 15 starting in Windows 2 structured mesh creation 45 Technical Support 17 Unstructured meshes 59 zone deletion 3 Mesh Label on Algebraic Elliptic Structured dialog 48 49 on Hyperbolic Structured dialog 53 on Unstructured dialog 61 Mesh menu 2 Mesh Output dialog 14 65 121 Index Formats 65 Mesh Smoothing 61 Meshes Algebraic mesh control 47 Algebraic meshes 45 Algebraic Arclength mesh control 47 Algebraic Edge Ortho mesh control 4
55. Max In the Mesh Control area of the dialog set Method to Elliptic Orthogonal and accept its default values Use the Mesh Label text field to name the new mesh orthogonal and click Create The Working dialog will appear while the new mesh is generated When done the new mesh will be dis played in the current Tecplot frame and added to its data set as an IJ ordered zone The resulting mesh is shown in Figure 3 2 6 a e a ee eee ees ae 5 a Oe meee SLE 2 T L a a a i SE AAA ID a a eae OLA a ee eres Ei I egg TN 3 RELL LE ee ge ae aE eg a E EE L222 eee gt Ca Z se gp LISSA aS ee 2 2 MOLLE LEZ WLLL L IEEE TE DLL LLLLLLLIPP PLL LLL A SESS SES EEE R LI LLLLLLLLL LILLE EE EL EELS PELAA a a a i A O p Hee ueliesienieare eaten EEEE EEEa mo imaina COL Tari A 1 2 3 5 O 5 X Figure 3 2 The Elliptic Orthogonal mesh 50 3 2 Creating Hyperbolic Meshes The working dialog features a Cancel button Clicking Cancel stops the mesh generation at the last iteration but does not delete the new mesh zone Note During the recording of a macro or project file a Cancel request is not recorded 3 2 Creating Hyperbolic Meshes Hyperbolic meshes are created by marching a single JMin boundary in a direction normal to itself to add a specified number of additional mesh lines The end points of the boundary can be unconstrained constrained to a line of constant X or Y or connected to each other peri od
56. OK 4 On the Circular Arc dialog use the Line Label text field to name this boundary imin1 then click Create Close the dialog We will now create the upper surface of the flat plate the second section of the IMin boundary On the Tecplot sidebar verify that the scatter plot layer option is active If it is not already active click on the check box then click Redraw 1 With the Tecplot Selector tool click on the end node or a node near the end of imin1 the circular leading edge boundary From the Boundary menu select Create Polyline this will call up the Polyline dialog 2 On the Polyline dialog click Select Endpt this will enter the values of the imin1 end point into the X and Y fields Now click Insert Before which will enter the values into the Con trol Points list Now manually enter the X and Y coordinates for the end points of the upper surface boundary using 9 5e 5 for X and 5e 5 for Y Click Insert After 98 7 1 Two Dimensional Flat Plate Example with a Structured Mesh Click Node Distribution On the Node Distribution dialog set Distribution to Tanh Num ber of Nodes to 8 Initial Spacing to 1 13e 5 Final Spacing to 1 6e 5 Click OK On the Polyline dialog use the Line Label text field to name this boundary imin2 then click Create We will now create the downstream or JMax boundary 1 First click on the end node or a node near the end of imin2 the upper surface boundary
57. REATEDEFAULTLINEFROMNURB ENTITYNUMBER lt integer gt REPLACEZONE lt integer gt Read an IGES file containing NURB curves This macro is intended only for use by Mesh Generator to write project files You should not use this macro in your macro files 86 Macro Commands Required Parameter Parameter ENTITYNUMBER Notes NURB entity number assigned internally not the IGES ID number Syntax lt integer gt Optional Parameter Parameter REPLACEZONE Syntax Description Syntax Default Notes lt integer gt 0 Zone to replace with the generated line CREATEELLIPTICSURFACE ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATEELLIPTICSURFACE optional parameters Create a new elliptic surface Where lt optional parameters gt is composed of name value pairs documented in the below list The variable name is followed by its type in parentheses If it is an Option parameter usually corresponding to an option menu the list of acceptable options is on the next line On the final line is its default value All of the string values must be enclosed by escaped apostrophes within the Command string Optional Parameters Parameter Syntax Default Notes REPLACEZONE lt integer gt 0 Zone to replace with the generated surface If 0 a new surface is created LABEL lt string gt nu The zone title to apply to the created sur face IMINBOUNDARY lt list gt
58. The Circular Arc dialog appears and the text fields displaying the same information used to create the line you selected You can now perform whatever actions are needed to define your new boundary e Conic Arc The Conic Arc dialog appears and the text fields displaying the same informa tion used to create the line you selected You can now perform whatever actions are needed to define your new boundary 31 Chapter 2 Creating Boundaries Extracted Line The Extract Selected Line dialog appears and the text fields displaying the same information used to create the line you selected You can now perform whatever actions are needed to define your new boundary Extracted Mesh The Extract Selected Mesh dialog appears and the text fields displaying the same information used to create the line you selected You can now perform whatever actions are needed to define your new boundary Imported NURB line The Node Distribution dialog appears You can now change the node distribution for your new boundary All other lines The Polyline dialog appears and the points from the selected line are dis played in the Control Points list You can now perform whatever actions are needed to define your new boundary 2 5 2 Labeling the Boundary A name can be assigned to each boundary you create This simplifies boundary selection when choosing from a list to create your mesh You may enter any characters you wish in the Line Label text field
59. To demonstrate this feature we will continue the blunt body example we last changed in Section 2 5 3 Creating the Boundary We will divide the boundary line into two parts To do this perform the following steps 36 2 7 Distributing Nodes Along the Boundaries 1 Using the Tecplot Selector tool select boundary line b10 in the current Tecplot frame Now click on the Boundary menu and select Extract From Selected Line This will call up the Extract Selected Line dialog 2 On the Extract Selected Line dialog set Start to 1 and End to 30 Use the Line Label text field to name this boundary b11 then click OK A new boundary will appear on top of the first half of b10 3 Now select b10 using the Tecplot Selector tool again and click on the Boundary menu to select Extract From Selected Line This will call up the Extract Selected Line dialog again 4 On the Extract Selected Line dialog set Start to 30 and End to 59 Use the Line Label text field to name this boundary b12 then click OK A new boundary will appear on top of the first half of b10 2 Distributing Nodes Along the Boundaries Mesh Generator provides several options for specifying how nodes are to be distributed along your boundary lines The distribution options allow you to concentrate the nodes near the ends of boundary lines and near specific locations along the boundaries To call up the Node Distri bution dialog click Node Distribution on eit
60. acing distribution 37 Examples 97 Exponential distribution 37 Exporting meshes 65 Extract From Selected Line dialog 33 Create button 35 End text field 34 Line Definition area 34 Line Label 35 reversing line direction 34 Start text field 34 Extract From Selected Line option 33 119 Index Extract From Selected Mesh 35 Extract Selected Mesh dialog 35 Create button 36 End text field 36 Max line option 36 Min line option 36 JMax line option 36 JMin line option 36 Line Definition area 36 Line Label 36 Start text field 36 Extracted lines editing 36 41 Extracting boundaries 108 Extracting new boundaries 33 EXTRACTLINE macro command 82 F File Import NURB File 16 Open Project 16 Save Project 16 Write Mesh File 16 65 File menu 2 Files saving 15 Final Spacing 39 H Help 17 Hide 2D Mesh 2 Hybrid meshes 1 extracting boundaries 108 Hyperbolic Structured 107 Hyperbolic mesh definition 45 Hyperbolic meshes 45 51 boundaries 51 boundary constraints 52 control 52 creating 51 creation 45 Hyperbolic Structured boundary extraction 114 creating 111 113 creation 102 editing 105 extracting boundaries 108 112 in hybrids 107 Hyperbolic Structured dialog 51 Layers JMax 52 boundary constraints 52 Create button 54 Initial Spacing 52 Max Smoothing Passes 53 mesh control 52 Mesh Label 53 Replace And Remove Layer 53 Reverse Marching Direction 53 Total Distance 52 I Max boundary orienta
61. and JMax surrounding the mesh be specified Each boundary consists of one or more boundary lines If a boundary is composed of more than one boundary line all lines for this boundary are con catenated to form a single line The direction of increasing node index is determined by the first line selected in the boundary Line sections defining a boundary must be added in the order in which they form the boundary For example the second line selected will be connected to the first line the fifth line selected will be connected to the first second third and fourth lines Mesh Generator requires that each sequential line used in the formation of a mesh boundary share a common node with the previous line The number of nodes in both the I and J directions is determined by the number of nodes in the corresponding boundaries The number of nodes for the IMin boundary must equal the number in the Max boundary likewise for the JMin and JMax boundaries The nodes must be coincident at the four corner points formed by the boundaries The direction of increasing node index must be the same in Min and Max boundaries Similarly the JMin and JMax bound aries must share the same direction of increasing node index Algebraic and Elliptic meshes are created with the Algebraic Elliptic Structured dialog This is called up by selecting Create Algebraic Elliptic Structured from the Mesh menu The Alge braic Elliptic Structured dialog is shown in Figure 3 1
62. art and End text fields Boundary Line options are e Min line The new boundary is extracted along the line Input indices are indices for J points e Max line The new boundary is extracted along the Max line Input indices are indices for J points e JMin line The new boundary is extracted along the J line Input indices are indices for I points e JMax line The new boundary is extracted along the J Max line Input indices are indices for I points No node distribution changes are allowed when extracting The only editing permitted on an extracted line is the modification of the starting and ending indices and the Boundary Line option Valid values for both starting and ending indices are from to the maximum number of nodes designated by Mx or the actual J index in either the I or J direction of the selected mesh For further information about values for the indices see Section 2 1 1 3 Using a Subset of the Specified Control Points 2 6 5 Labeling the Boundary A name can be assigned to each boundary you create This simplifies boundary selection when choosing from a list to create your mesh You may enter any characters you wish in the Line Label text field 2 6 6 Creating the Boundary The new boundary will be created and displayed in the current Tecplot frame after you click Create It will be a Tecplot I ordered zone The Extract Selected Mesh dialog will be removed after you click OK or Cancel
63. arted e Open project e Save Project e Write Mesh file 1 5 1 Import NURB File This allows you to read a curve from a NASA IGES NURBS ONLY file Clicking Read NURB file calls up a standard file input dialog box After the file is selected a one dimen sional Tecplot zone is created by distributing a default number of evenly spaced mesh points along the NURB curve The distribution of the mesh points along the NURB curve may be changed by editing the line using the Edit Selected Line option 1 5 2 Open Project Project files store the current state of a Mesh Generator session If a session is interrupted you may write a Project file exit Tecplot and continue at a later time by reading in the Project file 1 5 3 Save Project Project files store the current state of a mesh generation session and also include a history of your previous iterations When writing a project file a standard output dialog appears with the default extension shown as lay layout file If the Tecplot zones were saved ina plt plot file you would be unable to edit the mesh later 1 5 4 Mesh Output Mesh Generators s goal is to create a two dimensional structured and or unstructured finite element mesh for use by analysis codes If it is a multiple zone mesh the analysis code may also require information describing connectivity the between the zones This information is saved in a mesh file Clicking Mesh Output calls up the Mesh Output dialog I
64. ations of the control points If MULTIPLETANH distribution is used two more blocks must follow the first The second block contains the clustering points The X values of the final block contain the spacing for each point and the Y values contain the number of nodes to be placed in the preceding segment an integer value lt clusteringrawdata gt lt xyrawdata gt This must consist of two blocks The first block con tains the clustering points The X values of the final block contain the spacing for each point and the Y values contain the number of nodes to be placed in the preceding segment an integer value lt boundaryrawdata gt lt integer gt This is a list of integers zone numbers followed by lt integer gt an optional R The direction of the boundary is taken Bees from the first zone in the list The R if present indi R cates that this node order is to be reversed 95 Chapter 6 Extended Macros 96 cHAPTER7 Examples This chapter details four more advanced examples of meshes you can create in Mesh Genera tor The first is a two dimensional flat plate with flow over a circular leading edge which explores geometry and structured mesh creation mesh control methods such as Algebraic Arclength and Elliptic Thomas mesh smoothing the use of two polylines as a boundary and Mesh Generator s various node distributions methods such as tanh even and exponential spac ing The remaining three example
65. bution On the Node Distribution dialog set Distribution to Exponential Number of Nodes to 13 Spacing to Two Sided Initial and Final Spacing to 5 0e 4 and accept all other default values Click OK On the Polyline dialog use the Line Label text field to name this boundary bc2 then click Create Close the dialog 7 2 2 Creating a Hyperbolic Mesh We will now create the mesh for our example To do this perform the following steps 1 From the Mesh Generator menu select Create Hyperbolic Structured This will call up the Hyperbolic Structured dialog We will be using the zone numbers of the slat wing and flap as well as the two newly cre ated branch connectors as our JMin boundary You may enter these values either by typing them in manually clicking the Add From List buttons or using the Tecplot Selector tool in conjunction with the Add Selected buttons Add From List will read Add Selected when using the Selector tool You should enter the values in clockwise order starting at the lower edge of the flap the beginning of zone 11 The order of all the zones as entered clockwise is 11 12 15 5 6 7 8 9 14 1 2 3 4 14 10 15 and 13 See Figure 7 5 for details The sharp corners where bcl connects to the slat and bc2 connects to the wing are indica tors that the maximum number of smoothing steps need to be increased To reduce the com putational time an initial simpler mesh can be generated and repeatedly
66. c arcs They can also be created from existing boundary lines or by extracting from other I or IJ ordered Tecplot zones You can use Mesh Generator to convert Tecplot geometries to boundary lines Mesh Generator will also let you import an IGES NURB file which will allow you to create bound aries based on NURB definitions 2 1 Polylines A simple method for creating a boundary line is to specify a polyline A polyline is a set of connected line segments A line segment is defined by entering its starting and ending point coordinates Polylines are created by specifying the coordinates of more than two points The points you specify are called control points Control points are used to define the shape of a boundary Several options are available to let you specify control points they may be entered manually selected from the end point of an existing boundary line or converted from a Tecplot polyline geometry You may not define two identical control points one after another To call up the Polyline dialog in Mesh Generator select the Boundary menu then choose the Create Polyline The Polyline dialog is shown in Figure 2 2 19 Chapter 2 Creating Boundaries Hesh Generator Ea File Mesh Create Polyline Create Circular Arc Create Conic Arc peate From selected lime Ermact hom selected me Ermact Rom selected Mesi Eqit selected One Selected Line Into Heete selected Line Figure 2 1 The Bou
67. called up as shown in Figure 4 1 Each closed loop boundary may consist of more than one boundary line The outer boundary along with any inner boundaries are specified in the Closed Loop Boundaries area on the Unstructured dialog Each text line in the Select Mesh Boundary Zone Numbers list represents one boundary To add a boundary to the list click New Boundary This will generate a high lighted empty line shown as Incomplete in the field You may select and use more than one boundary line to make up this boundary Lines may be chosen in one of two ways e If no boundary line is selected the button below New Boundary will read Add From List Clicking on this button calls up the Add From List dialog This lists all the boundary lines available for use in the closed loop boundary You may select one or more boundary lines to be added to the list Clicking OK will add their zone numbers to the list e Ifa boundary line is selected using the Tecplot Selector tool Add From List will change to read Add Selected Clicking Add Selected will add the selected line s zone number to the list 59 Chapter 4 Creating Unstructured Meshes Closed Loop Boundaries Select Mesh Boundary zone Numbers Mew Boundary alaen ee Delete Reverse OTe Ton Mesh Control Maximum Calls 10000 Mesh Smoothing Mesh Label Create Relate Close Help Figure 4 1 The Unstructured dialog All boundary lines for a boundar
68. ce button will replace a selected point with the entered values The Delete button will remove a selected point from the list 2 7 4 Interpolation The Interpolation area of the Node Distribution dialog lets you select the type of interpolation which will be used to control the polyline boundary shape while distributing nodes along it The interpolation is based on the specified control points There are two Interpolation options available 40 2 8 Editing a Selected Line e Cubic the default e Linear No interpolation will be performed for NURB lines circular or conic arcs as they are treated analytically The following example creates a boundary with a multiple hyperbolic tangent node distribu tion similar to that shown in Figure 2 11 To create the boundary perform the following steps 1 Using the Tecplot polyline geometry tool draw a polyline with four segments This will require five clicks on your mouse which will create five control points 2 Now use the Tecplot Selector tool to select the polyline then click on the Boundary menu and select Create Polyline This will call up the Polyline dialog 3 On the dialog click Convert Polyline Geometry Insert After This will enter the values of your polyline into the Control Points list 4 Now click Node Distribution On the Node Distribution dialog set Distribution to Multiple Tanh Number Of Nodes to 31 and Initial and Final Spacing to 0 01 Now creat
69. ce with X constant constraints making a C mesh ADDONCOMMAND 89 Chapter 6 Extended Macros ADDONID Mesh Generator COMMAND CREATEHYPERBOLICSURFACE BOUNDARY 1 2 TOTALDISTANCE 5 0 IMINCONSTRAINT XCONSTANT IMAXCONSTRAINT XCONSTANT CREATEUNSTRUCTUREDSURFACE Syntax ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATEUNSTRUCTUREDSURFACE optional parameters RAWDATA lt boundaryrawdata gt Description Create a new algebraic or elliptic surface The RAWDATA section must contain lists of zone numbers which define one external counter clockwise boundary and zero or more internal clockwise boundaries See 6 5 Raw Data on page 95 for a description of the format of this data Optional Parameters Parameter Syntax Default Notes REPLACEZONE lt integer gt 0 Zone to replace with the generated surface If 0 a new surface is created LABEL lt string gt a The zone title to apply to the created sur face MAXCELLS lt integer gt 100000 The maximum number of cells to be used to create the surface Must be greater than the number of segments of all boundaries com bined SMOOTHING lt boolean gt FALSE If TRUE smooths the final mesh Example Create an unstructured surface with two boundaries reversing the direction of the second boundary ADDONCOMMAND ADDONID Mesh Generator 90 Macro Commands COMMAND
70. coordinates of the end point closest to a node selected with the Tecplot Selector tool This allows an exact specification of a given end point 25 Chapter 2 Creating Boundaries Conic Arc Line Definition A T Start 0 select endpi End 0 aooo SPE endoe Vertex fi jt Length Ratio U 5 Mode Distribution Line Label Create Renlace Close Help Figure 2 4 The Conic Arc dialog without having to manually enter the values It avoids mismatch errors which can create prob lems when attempting to combine the multiple boundaries of a mesh The Length Ratio defines where the conic arc curve intersects the bisection line creating the middle point mid point between the Start and End points and the Vertex This number is the ratio of length from the middle point to the intersection point and the length from the middle point to the vertex The value entered in the text field for the Length Ratio determines the ana lytic shape of the conic arc Acceptable values for the Length Ratio are 0 lt Length Ratio lt 1 0 Also e Ellipse 0 lt Length Ratio lt 0 5 e Parabola Length Ratio 0 5 e Hyperbola 0 5 lt Length Ratio lt 1 0 26 2 3 Conic Arcs 2 3 2 Node Distribution The number of nodes the distribution option and the interpolation on a conic arc is set by clicking on Node Distribution When you click Node Distribution the Node Distribution dialog will be called up This i
71. d When done the new mesh will be displayed in the current Tecplot frame and added to its data set as an IJ ordered zone The resulting mesh is shown in Figure 3 5 When either the Algebraic Elliptic Structured or Hyperbolic Structured dialog is called up to edit a two dimensional mesh the Replace button will be active Clicking on the Replace button will not generate the new IJ ordered zone it will only replace the current zone The Delete Selected Mesh option on the Mesh menu is only active when you select a two dimensional mesh in the current Tecplot frame It will delete the mesh you have selected only if it is not used in any of existing zones Otherwise an error message will appear 3 4 Mesh Connectivity Multi block flow solvers analyzing multiple zones must be instructed on how mesh zones are connected to one another in order to come up with the correct solution When two meshes are not contiguous you cannot instruct a flow solver to treat the two mesh zones as a single region There are two ways to automatically create mesh connectivity in the Mesh Generator such that the mesh points on the connecting boundary will be exactly coincident The first is to use the same boundary line for the two meshes you wish to connect which will be discussed shortly The second method is to extract a boundary line from an existing mesh which is covered under Section 2 6 Extracting New Boundaries 55 Chapter 3 Creating Structur
72. d by determining the point on the line closest to the values you enter Spacing at this clustering point is enforced on both sides of the point The Nodes is the number of the nodes to be placed on the line section between two physically adjacent clustering points including the clustering points In Figure 2 11 the Nodes in section 1 is four since the section contains four mesh nodes including the nodes that are automatically placed at the clustering points at the ends of the sec tion The Nodes for the last section which is section 4 in this case cannot be specified by the user This section is self defined by the last cluster point and the last point on the line The number of nodes placed in this section is calculated in such a way that the total number of 39 Chapter 2 Creating Boundaries 0 8 S a secon Z o 0 6 gt 0 44 Line Control Points 0 2 e Node Points lt Clustering Points O 0 2 0 4 0 6 0 8 1 1 2 X Figure 2 11 Cluster points dividing a line into sections nodes on the line will be equal to Number Of Nodes The text fields are used to modify the values Replace Add and Delete are the available option buttons The Add button will add your entered values to the list below the selected point If the list is empty it will list your values If the list is empty and you have not selected a point clicking Add will call up a warning mes sage indicating that you must select a point The Repla
73. d meshes 61 Reverse Marching Direction 53 saving 65 smoothing 61 Unstructured 4 59 Unstructured mesh control 61 with PLOTS3D files 68 Modified C Meshes 111 Multiple Tanh 39 Multiple Tanh distribution 38 N New Boundary button 59 Node distrbution Exponential 37 Node Distribution 6 As Is 37 defaults 22 Node distribution 37 Nodes 39 clustering control points in Multiple Tanh 38 Cubic 39 default circular arc distribution 25 default for conic arcs 27 Even Spacing 37 Final Spacing 39 Inital Spacing 39 interpolation options 40 Multiple Tanh 38 39 Polynomial 38 spacing 39 Tanh 37 Node Distribution dialog 6 37 Nodes 39 122 Cubic Interpolation 39 Even Spacing 37 Exponential 37 Final Spacing 39 Inital Spacing 39 Interpolation area 40 interpolation options 40 Multiple Tanh 38 39 node direction 38 node index order 38 node spacing 39 Number Of Nodes 38 Polynomial 38 Replace Add and Delete buttons 40 Reverse Line Direction 38 Tanh 37 Node Distritbution dialog As Is 37 Node index order 38 Node index order default direction 38 Node spacing 39 Number Of Nodes option 38 NURB line editing 41 O On Line Help 17 Open Project 16 Options Nodes 39 Counter Clockwise 24 Create Circular Arc 5 Create Conic Arc 25 Create From Selected Line 31 Create Hyperbolic Structured 51 Create Polyline 5 Create Unstructured 59 Delete Selected Line 42 Delete Selected Mesh 55 Edit Selected Mesh 55 Extract From Select
74. dary The Replace and Remove 1 Layer buttons are only active when Edit Selected Mesh is chosen The Remove 1 Layer option allows you to remove the last layer of mesh 3 2 3 Labeling a Hyperbolic Structured Mesh A name can be assigned to each mesh you create The Mesh Label text field is located at the bottom of the Hyperbolic Structured dialog you may enter any characters you wish 3 2 4 Creating a Hyperbolic Structured Mesh To create a Hyperbolic Structured mesh from your existing blunt body shape perform the fol lowing steps 1 Choose Create Hyperbolic Structured from the Mesh menu 2 Use either Add From List or Add Selected next to the Enter Mesh Boundary Zone Numbers text field to enter your JMin boundary In this case we will use the JMax boundary Select b5 to be our new JMin boundary 53 Chapter 3 Creating Structured Meshes 3 Inthe Mesh Control area of the Hyperbolic Structured dialog set the following values For Layers JMax enter 50 For Total Distance enter 2 In Constraints use the Min drop down to set Y Constant Finally use the Mesh Label text field to name the new mesh hyperbolicy Click Create The Working dialog will appear while the new mesh is gener ated When done the new mesh will be displayed in the current Tecplot frame and added to its data set as an IJ ordered zone The resulting mesh is shown in Figure 3 4 yl 4 OM MOLLE hf MOTEZZAEEEE WU MELEE WW BA
75. dary 114 Creating the Unstructured Mesh 115 Index I17 vi cHapTteR1 Getting Started Mesh Generator is a Tecplot add on that provides the ability to create multi zone two dimen sional meshes Both IJ ordered structured and finite element unstructured meshes may be generated using Mesh Generator In addition you can create hybrid meshes that combine both structured and unstructured mesh zones As an add on Mesh Generator is a shared library dynamic link library in Windows which is loaded at run time by the LOADADDON macro command in the tecplot add file in your Tecplot Home Directory Please refer to the Tecplot User s Manual for further information about Tecplot add ons 1 1 Starting and Stopping Mesh Generator The first thing you must know is how to begin a session in Mesh Generator and how to end a session The following describes how to start and stop Mesh Generator on various operating systems 1 1 1 Starting and Stopping on UNIX Systems Once Mesh Generator has been installed simply start Tecplot by your usual method The words Mesh Generator should appear in the Tecplot Tools menu On a UNIX operating system to manually load Mesh Generator type tecplot loadaddon lt fullpathname gt libmeshgen In either case from the Tecplot menu bar you should then select the Tools menu then select Mesh Generator The Mesh Generator main dialog will appear Mesh Generator is now run ning You may move the Mesh
76. der To remove a boundary from the list select it then click Delete To edit a boundary you must first remove it then create a new boundary 4 2 Unstructured Mesh Control The Maximum Cells text field indicates the maximum number of triangular cells which will be used to fill an enclosed region This number must be greater than the total number of bound ary nodes external and internal boundaries or an error will be displayed It is recommended you not set this number too large or it may result in the unnecessary usage of memory The mesh density created by Mesh Generator depends solely on the node distribu tion along the boundaries The denser the boundary the denser the resulting mesh will be The Mesh Smoothing check box gives you the ability to use a Laplacian type smoothing oper ator to smooth small irregularities A name can be assigned to any mesh you create The Mesh Label text field is located at the bottom of the dialog you may enter any characters you wish Clicking Create will create a new unstructured zone and add it to the data set of the current frame The initial boundary triangulation will be shown in the current frame then refreshed after each100 points have been inserted You may interrupt mesh creation by clicking Cancel on the Working dialog 4 3 Editing and Deleting Unstructured Meshes Select the desired unstructured mesh to edit then click Edit Selected Mesh from the Mesh menu The Unstructured dialo
77. e Label text field to name this boundary sb2 then click OK With the Tecplot Selector tool select mesh1 a third time Now select Extract From Selected Mesh from the Boundary menu to call up the Extract Selected Mesh dialog again Set Boundary Line to Max and set Start and End to 1 and mx Use the Line Label text field to name this boundary sb3 and click OK Repeat this process for mesh2 of the wing wb1 and so forth and mesh3 of the flap fb1 and SO On 108 7 3 Three Element Airfoil Example with a Hybrid Mesh 7 3 4 Creating a Circular Outer Boundary The ideal outer boundary varies depending on flight conditions A circular boundary that extends approximately six chord lengths outward is useful for illustrating how to link the struc tured mesh components into one computational domain To do this perform the following Steps 1 Select Create Circular Arc from the Boundary menu This will call up the Circular Arc dia log 2 On the Circular Arc dialog set Specify to Center Starting Point Arc Angle Set Center to 0 7 for X and 0 for Y Set Start to 0 7 for X and 6 for Y Set Arc Angle to 360 3 Click Node Distribution On the Node Distribution dialog set Distribution to Even Spacing Number Of Nodes to 100 and Interpolation to Cubic Click OK 4 On the Circular Arc dialog use the Line Label text field to name this boundary arcl Click Create You may want to click on Data Fit from the View
78. e Tecplot Selector tool 2 On the Polyline dialog click Select Endpt to enter the X and Y values into the text fields then click Insert Before to add the values to the Control Points list Still using your Tecplot Selector tool click on a node at or near the start point of the downstream boundary jmax1 On the Polyline dialog click Select Endpt then click Insert After Click Node Distribution On the Node Distribution dialog set Distribution to Even Spac ing Number of Nodes to 6 Click OK On the Polyline dialog use the Line Label text field to name this boundary imax2 then click Create 99 Chapter 7 Examples We will now create the symmetry plane the JMin boundary 1 First click on the start node or a node near the start of imin1 the circular leading edge boundary with the Tecplot Selector tool On the Polyline dialog click Select Endpt to enter the X and Y values into the text fields then click Insert Before to add the values to the Control Points list Still using your Tecplot Selector tool click on a node at or near the start point of imax1 the first segment of the farfield boundary On the Polyline dialog click Select Endpt then click Insert After Click Node Distribution On the Node Distribution dialog set Distribution to Exponential Number of Nodes to 23 Spacing to Two Sided Initial Spacing to le 7 Final Spacing to le 6 Click OK On the Polyline dialog use the Line Label
79. e connectivity list for the tetrahedra will be empty The integer flags for the triangles indicate to FAST what type of boundary each triangle represents This is extraneous in a two dimensional mesh so all of these flags are set to 2 surface Binary files contain two records The first record contains the number of nodes the number of triangles and the number of tetrahedra and the second record contains all of the remaining data 5 1 2 3 Multi Zone Formats PLOT3D s multi zone formats are the same as the single zone formats above except that one additional integer is added at the beginning of the file which specifies the number of zones contained in the file In binary files this integer is con tained in a separate record 5 2 Mesh Conversion Mesh Generator allows you to convert all output mesh zones to a single unstructured zone either triangular or quadrilateral These options are available in the Mesh Conversion area of the Mesh Output dialog With either of these options all output mesh zones are converted to 69 Chapter 5 Exporting Meshes the desired type and combined into a single zone and redundant nodes and cell edges are elim inated This process is illustrated in Figure 5 2 Redundant nodes and cell edges are identified using the same logic as is used for identifying inter mesh zone connections Each boundary line identified as an inter mesh connection will result in only a single set of nodes and cell
80. e three clus ter points by setting X and Y values that approximate positions along the new line set Spacing to 0 01 and set Nodes to 4 for the first segment 7 for the second segment and 6 for the third segment Click Add after entering the values for each cluster point Set Interpo lation to Cubic Click OK 5 On the Polyline dialog use the Line Label text field to name this boundary b13 and click Create The new boundary line will appear in the current Tecplot frame Note If your new boundary line does not look like that in Figure 2 11 you may wish to click on the Scatter plot layer button on the Tecplot sidebar 2 8 Editing a Selected Line To edit a line select it using the Tecplot Selector tool then choose Edit Selected Line from the Boundary menu The option is activated only when you select a line in the current Tecplot frame The dialog which results will depend upon the type of line you have selected Available options are e Created polyline Polyline dialog is called up e Created circular are Circular Arc dialog is called up e Created conic are Conic Arc dialog is called up 41 Chapter 2 Creating Boundaries Created by extraction from a line Extract From Selected Line dialog is called up Created by extraction from a mesh Extract From Selected Mesh dialog is called up NURB line NURB curve dialog is called up All other lines Polyline dialog is called up Any of the input values in the
81. each boundary you create This simplifies boundary selection when choosing from a list to create your mesh The Line Label text field is located at the bottom of the Circular Arc dialog you may enter any characters you wish 2 2 4 Creating a Circular Arc Boundary The new circular arc boundary will be created and displayed in the current Tecplot frame after you click Create It will be a Tecplot I ordered zone After clicking Create the Circular Arc dialog will be reset with its default values 2 3 Conic Arcs The conic arc option allows you to create analytically defined boundaries such as ellipses parabolas and hyperbolas To call up the Conic Arc dialog click Boundary on the Mesh Gen erator menu then select Create Conic Arc The Conic Arc dialog is shown in Figure 2 4 2 3 1 Line Definition The Line Definition area of the Conic Arc dialog allows you to input values that control the shape and extent of your conic arc A conic arc is defined by entering the X and Y coordinates of the Start and End points of the arc and entering the Vertex which joins the Start and End point to form a triangle enclosing the conic arc The X and Y coordinates for these points are entered in the text fields labeled X and Y Next to the X and Y text fields for Start and End are two Select Endpt buttons which are active only when another boundary is selected in the current Tecplot frame The Select Endpt buttons allow you to automatically enter the
82. ed Line 33 Extract From Selected Mesh 35 Hide 2D Mesh 2 Interpolation for nodes 40 Max Smoothing Passes 53 Mesh Smoothing 61 Node Distribution 6 37 Number Of Nodes 38 Replace And Remove 1 Layer 53 Reverse Direction 61 Reverse Line Direction 38 Reverse Marching Direction 53 Selected Line Info 42 Write Mesh File 65 Orthogonality Relaxation 49 P Parameters for Hygrid macro commands 75 PLOT3D files 68 multi zone format 69 two dimensional format 69 unstructured format 69 uses with meshes 68 Poisson s equation solving with Elliptic Orthogonal mesh control 49 solving with Elliptic Thomas mesh control 48 Polyline dialog 5 19 Control Points area 20 Convert Polyline Geometry Insert After button 21 Create button 23 Delete button 21 entering Control Points 20 Insert After button 21 Insert Before button 21 line definition 20 Line Label 22 Node Distribution button 22 Replace button 21 Select Endpt button 20 Start and End text field 22 Polylines 19 control points 19 converting geometries 21 Delete Selected Line 3 deleting 42 editing 41 editing permitted 36 information 42 Node distribution 37 Polynomial distribution 38 R Read IGES File dialog 30 READNURBFILE macro command 86 123 Index READPROJECTFILE macro command 92 Recording Macro files 17 REMOVELAYER macro command 91 Replace And Remove Layer 53 Replace button 21 Reverse Direction 61 Reverse Line Direction option
83. ed Meshes OLI LAT My QO LALPLLLLPLLIILSZIIEEE BEE UY SELLE 1 SSS pe LL LLALLLL LLL HERR AAAA A TI AALL 0 E a WSS S Mi 5 O 5 X Figure 3 5 The modified Hyperbolic Structured mesh Note You can only use Tecplot mesh files to specify various types of mesh connectivity when outputting the mesh The restricted format of PLOT3D files cannot store this information For a discussion of how connectivity is written into Tecplot mesh files see Chapter 5 Exporting Meshes To create a simple connected mesh from our existing example perform the following steps 1 In the Polyline dialog enter the values 5 0 for X and Y in the X and Y text fields Click Insert Before Now enter 5 for X and 1 for Y Click Insert After Click Node Distribution and set Distribution to Even Spacing and Number Of Nodes equal to 5 on the Node Distri bution dialog On the Polyline dialog use the Line Label text field to name this boundary b6 Click Create The new boundary will be drawn in your current Tecplot frame Close the Polyline dialog 56 3 4 Mesh Connectivity 2 Under Mesh on the Mesh Generator menu choose Create Hyperbolic Structured from the menu You may either use Add From List to specify the JMin boundary of the mesh or you may select boundaries with the Selector tool which will change the button to read Add Selected Use either method to add b6
84. ed above to create meshes for the wing and flap Create m2 for the wing by entering zones 15 5 6 7 8 9 10 and 15 for your JMin boundary in that order Create m3 for the flap using zones 16 11 12 13 and 16 for your JMin boundary in that order 7 3 3 Extracting to Create Internal Boundaries The outermost boundary JMax of each of the hyperbolic meshes you have created will be used as the internal boundaries for the unstructured portion of our hybrid mesh These outer boundaries need to be explicitly defined This is done by creating boundaries from each of the hyperbolic meshes To create these boundaries perform the following steps 1 With the Tecplot Selector tool select mesh1 Now select Extract From Selected Mesh from the Boundary menu This calls up the Extract Selected Mesh dialog Accept the default boundary line IMin In the Line Definition area of the Extract Selected Mesh dialog the Start and End text fields refer to the J range Set Start to 1 and End to mx to specify the complete boundary Use the Line Label text field to name this boundary sb1 then click OK With the Tecplot Selector tool select mesh1 again Now select Extract From Selected Mesh from the Boundary menu to call up the Extract Selected Mesh dialog again In the Line Definition area of the Extract Selected Mesh set Boundary Line to JMax The Start and End text fields now refer to the I range Set Start to 1 and End to mx Use the Lin
85. edges instead of two sets one for each mesh zone f PAPA VAAL NM Figure 5 2 A converted mesh Note The PLOT3D mesh file format does not support quadrilateral unstructured meshes 5 2 1 Conversion to a Single Quadrilateral Zone Specifying conversion to a single quadrilateral mesh will result in a mesh whose cells are iden tical in appearance to the cells of each individual mesh being converted In other words cells of triangular unstructured meshes will be output as quadrilaterals with one collapsed face and cells of structured meshes will be output as equivalent quadrilateral cells Using this conversion option it is possible to generate meshes for analysis software which requires quadrilateral unstructured meshes Quadrilateral cells may be created as an arbitrary number of structured meshes and then output using this option As noted above all internal boundaries which represent connections between the original meshes are eliminated in the converted mesh If the mesh is output to a Tecplot mesh file the boundary regions corresponding to the remaining boundaries are included in the mesh file to enable analysis software to identify cell edges which lie on the boundaries of the mesh 70 5 2 Mesh Conversion 5 2 2 Conversion to a Single Triangular Zone Specifying conversion to a single triangular mesh will result in each mesh cell of the original meshe
86. es and Meshes 6 Click Node Distribution On the Node Distribution dialog set Distribution to Exponential Number Of Nodes to 15 and accept all other default settings Click OK 7 On the Polyline dialog click Replace then close the dialog 8 Click on b5 the JMax boundary line Then choose Edit Selected Line from the Boundary menu 9 Click Node Distribution On the Node Distribution dialog set Distribution to Polynomial Number Of Nodes to 29 click on the One Sided Initial option and accept all other default settings Click OK 10 On the Circular Arc dialog click Replace then close the dialog The result of these changes is shown in Figure 1 9 6 4 gt 2 0 2 4 2 0 2 4 X Figure 1 9 The existing boundaries with the node distribution changed 1 4 2 Modifying Meshes Next we will change the existing mesh Deactivate the Hide 2D Mesh option then click Redraw Now perform the following steps 13 Chapter 1 Getting Started 1 Click on the existing mesh labeled arclength then go to the Mesh menu and click Edit Selected Mesh 2 Under Mesh Control on the Algebraic Elliptic Structured dialog set Method to Elliptic Laplace and accept its default values Use the Mesh Label text field to rename the new mesh laplace and click on Replace The Working dialog will appear while the new mesh is generated Close the dialog when mesh generation has completed
87. eter O Gorman Ppmtopict 1990 Ken Yap TRADEMARKS Mesh Generator Tecplot RS Tecplot Preplot Framer and Amtec are registered trademarks or trademarks of Amtec Engineering Inc Encapsulated PostScript FrameMaker PageMaker PostScript Premier Adobe Systems Incorporated Ghost script A laddin Enterprises Linotronic Helvetica Times Allied Corporation LaserWriter Mac OS X Apple Computers Incorporated AutoCAD DXF Autodesk Incorporated Chears ChevronTexaco Corporation Compaq Computer Corporation Elan License Manager is a trademark of Elan Computer Group Incorporated Alpha DEC Digital LaserJet HP GL HP GL 2 PaintJet Hewlett Packard Company X Designer Imperial Software Technol ogy Builder Xcessory Integrated Computer Solutions Incorporated IBM RS6000 PC DOS International Busi ness Machines Corporation Bookman ITC Corporation VIP Landmark Graphics Corporation X Windows Massachusetts Institute of Technology MGI VideoWave MGI Software Corporation ActiveX Excel MS DOS Microsoft Visual Basic Visual C Visual J Visual Studio Windows Windows Metafile Microsoft Corpora tion HDF NCSA National Center for Supercomputing Applications UNIX OPEN LOOK Novell Incorporated Motif Open Software Foundation Incorporated Gridgen Pointwise Incorporated Eclipse FrontSim Schlum berger Limited IRIS IRIX OpenGL Silicon Graphics Incorporated Open Windows Solaris Sun Su
88. fields you can use one of the four action buttons directly below the fields These are e Replace Replaces a selected point in the Control Points list with the values shown in the X and Y text fields It is used to edit an existing control point and is inactive until at least one control point is defined e Insert Before Adds a control point to the list by inserting the values shown in the X and Y text fields either before a point you have selected in the list or as the first point if the list is empty e Insert After Adds a control point by inserting the values shown in the X and Y text fields after a point you have selected in the list or as the first point if the list is empty e Delete Removes a selected control point from the list It is inactive until at least one con trol point is defined 2 1 1 2 Converting Polyline Geometries to Boundaries To the right of the four action buttons is the Convert Polyline Geometry Insert After button This is active only when a Tecplot polyline geometry is selected in the current frame with the Selector tool Clicking on 21 Chapter 2 Creating Boundaries this button will convert a selected polyline geometry into a set of control points which are then inserted after a selected point in the Control Point list This will allow you to draw a polyline with the Tecplot drawing tool then convert it directly into a boundary without having to man ually enter the control points Note
89. g you may enter any characters you wish 3 1 4 Creating an Algebraic Structured Mesh Clicking on the Create button will generate the new algebraic structured mesh The Working dialog will appear while the new mesh is generated When done the new mesh will be dis played in the current Tecplot frame and added to its data set as an IJ ordered zone Note During the recording of a macro or project file a Cancel request is not recorded For an example of Algebraic Structured mesh creation see Section 1 3 3 Creating the Mesh 3 1 5 Elliptic Mesh Control The last three methods listed in the Method dropdown in the Mesh Control area of the Alge braic Elliptic Structured dialog are fore Elliptic meshes These are e Elliptic Laplace Solves the Laplace equation This method is useful for generating evenly spaced meshes When this method is used for stretched meshes it will try to even the mesh spacing which may be undesirable Selecting this method requires two other mesh control parameters Maximum Iterations and Elliptic Relaxation e Elliptic Thomas Solves Poisson s equation with source terms added to retain the stretch ing near the walls This option is useful for generating stretched meshes Selecting this method also requires the Maximum Iterations and Elliptic Relaxation parameters 48 3 1 Creating Algebraic or Elliptic Meshes Elliptic Orthogonal Solves Poisson s equation with source terms added to force
90. g on a blank region of the frame 2 Enter the IMin boundary by selecting the Add From List on the Algebraic Elliptic Struc tured dialog which is shown in Figure 1 7 Select the boundary line b3 the boundary corre sponding to zone 3 from the list Click OK 3 For the Max boundary enter boundary line b4 by using the Selector to select it in the cur rent frame Note Add From List changes to read Add Selected Click Add Selected Use any method to define JMin as b1 and b2 and finally JMax as b5 4 Accept the default Mesh Control Method of Algebraic Arclength name the mesh as arclength in the Mesh Label text field then click Create The Working dialog will appear while the new mesh is generated When mesh generation is complete close the dialog 10 1 4 Modifying and Converting Boundaries and Meshes Algebraic Elliptic Structured Boundaries Enter Mesh Boundary zone Numbers Ihin Add From List max _Add From List umn D ASG Fr List Jhax Po Add From List Mesh Control hethod Algebraic Arclangth Orthogonality Relaxation 0 1 Maximum Iterations 100 Elliptic Relaxation Mesh Label Create Replace Close Help Figure 1 7 The Algebraic Elliptic Structured dialog The resulting mesh is shown in Figure 1 8 Leave this example in your current Tecplot frame as we will refer to it again in following sec tions 1 4 Modifying and Converting Boundaries and Meshes
91. g will be called up This option is only active when the selected unstructured mesh was created using Mesh Generator Clicking Replace will replace the selected unstructured mesh zone with a newly created mesh 61 Chapter 4 Creating Unstructured Meshes Clicking Create will generate the new unstructured zone and add it to the data set of the current frame The Delete Selected Mesh option is active only when you select a two dimensional unstruc tured mesh in the current Tecplot frame Clicking on it will remove the unstructured mesh you have selected 4 3 1 Unstructured Mesh Creation To create a simple unstructured mesh we will use our existing blunt body Before starting use the Delete Selected Mesh and Delete Selected Line options from the Mesh and Boundary menus to remove the meshes we have created so far and boundary line b6 created in Section 3 4 Mesh Connectivity Once you have the original blunt body configuration perform the following steps 1 Using the Tecplot circle geometry tool create a circle around the blunt body To do this put the circle geometry crosshair in the center of the blunt body then click and drag to form a circle which encompasses the blunt body 2 Select the circle with the Tecplot Selector tool then select Create Circular Arc from the Boundary menu 3 On the Circular Arc dialog click Convert Circle Geometry This will enter the coordinates of the circle you have just drawn int
92. h from the Mesh menu This will call up the Hyperbolic Structured dialog 2 On the Hyperbolic Structured dialog set Layers JMax to 50 Total Distance to 1 and Max Smoothing Passes to 10000 Accept all other default values and click Replace The Working dialog will appear while the mesh is regenerated 105 Chapter 7 Examples The resulting changes are shown in Figure 7 6 Figure 7 6 The modified Hyperbolic Structured mesh Note The time required to regenerate will vary greatly depending upon the speed of the com puter 7 3 Three Element Airfoil Example with a Hybrid Mesh For this example load the data file STEC9 OHOME examples meshgen airfoil plt After the file has loaded switch the Tecplot frame mode to 2D and click Scatter on the plot layer buttons We are now ready to begin 7 3 1 Creating Element Extensions Element extensions are lines which are added to the trailing edge of each element in this case our slat wing and flap They allow your meshes to be extended aft of the surface with the intent of resolving the mixing regions at the trailing edge of the elements They must be created in the anticipated direction of the streamlines in this region To create them perform the fol lowing steps 106 7 3 Three Element Airfoil Example with a Hybrid Mesh From the Tecplot sidebar click on the polyline geometry tool Use it to draw a horizontal polyline about 0 06 units long anywhere in
93. h is regenerated Note On some slower systems this mesh may take up to 30 minutes to generate the optimal mesh Increasing Maximum Cells to 15000 is sufficient to demonstrate how the edit and replace features work 7 4 Three Element Airfoil Example with a Modified C Mesh In the previous example the optimal mesh resulted in thousands of very small triangular cells clustered around the downstream ends of the extensions to the slat wing and flap These cells are the result of the mesh stretching which is necessary in the initial mixing layer but not as the flow mixes out downstream Ideally we want the mesh on the extensions to be less stretched as we move downstream This will result in fewer triangular cells in a region where they are unnecessary We will accomplish this by using the hyperbolic method in a unique way To start the process we need to switch the frame mode to 2D Then load the airfoil plt file again using Tecplot s Load Data File s option 7 4 1 Creating the Hyperbolic Meshes We will create a hyperbolic mesh around each element in this case the slat wing and flap We will then extract the JMin and JMax boundaries from each mesh we have created 1 Select Create Hyperbolic Structured from the Mesh menu 2 We will be using the zone numbers of the slat as our JMin boundary You may enter these values either by typing them in manually clicking the Add From List buttons or using the Tecplot Selector tool in conju
94. hen use the Line Label text field to name this sc Click OK Select s1 On the Extract Selected Mesh dialog set Boundary Line to JMax Line Accept all other default values then use the Line Label text field to name this sd Click OK These four exterior lines will form one closed loop interior boundary when you created your unstructured mesh Repeat this process for the w1 and w2 on the wing Repeat it a third time for f1 and f2 on the flap 7 4 5 Creating the Circular Outer Boundary We will now create the outer boundary for the unstructured mesh To do this perform the fol lowing steps 1 Select the Tecplot circle tool and click Tool Details on the Tecplot sidebar In the Geometry dialog set the Origin X and Y value to 0 Also set the Circle Radius to 6 Click Place and close the dialog To view the circle geometry select Fit to Full Size under the View menu on the Tecplot menu bar On the Boundary menu select Create Circular Arc This will call up the Circular Arc dialog With the Selector tool click on the circle geometry On the Circular Arc dialog click Con vert Circle Geometry This will enter the values of your circle into the text fields in the Arc area of the dialog Now click Node Distribution On the Node Distribution dialog set Distribution to Even Spacing and Number Of Node to 40 Accept all other default values then click OK 114 7 4 Three Element Airfoil Example with a Modified C Mesh
95. her the Polyline Circular Arc or the Conic Arc dialogs These may be accessed from the Boundary menu 2 7 1 Node Distribution The Distribution option on the Node Distribution dialog makes other areas on the dialog active or inactive depending upon the selection Available Distribution options are e As Is Do nothing and copy the current node distribution e Even Spacing Nodes are distributed evenly with constant spacing e Exponential One or Two Sided Nodes are distributed in terms of an exponential func tion The default value is Two Sided where the Initial and Final Spacing are set to 0 001 When One Sided Initial is selected the Initial Spacing is required and clustering will occur near the starting point of the line When One Sided Final is selected the Final Spacing is required and clustering will occur near the ending point of the line e Tanh Nodes are distributed with a hyperbolic tangent where clustering will be done at both ends of the line Tanh is similar to the exponential distribution but the stretching is more gradual near the end points Both Initial and Final Spacing is required 37 Chapter 2 Creating Boundaries e Multiple Tanh Nodes are distributed in a series of hyperbolic tangent functions The result is a series of segments with the mesh stretched toward the end of each segment Selecting Multiple Tanh distribution will activate the Multiple Tanh area located immedi ately bel
96. hes 55 Mesh Connectivity 55 Creating Unstructured Meshes 59 Selecting Closed Loop Boundaries 59 Unstructured Mesh Control 61 Editing and Deleting Unstructured Meshes 61 Unstructured Mesh Creation 62 Exporting Meshes 65 Selecting the Format 65 The Tecplot Format 66 The PLOT3D Format 68 Mesh Conversion 69 Conversion to a Single Quadrilateral Zone 70 Conversion to a Single Triangular Zone 71 Extended Macros 73 The ADDONCOMMAND Tecplot Macro 73 Macro Command Summary 74 Macro Commands 75 Parameter Assignment Values 94 Contents CHAPTER 7 CHAPTER 8 Raw Data 95 Examples 97 Two Dimensional Flat Plate Example with a Structured Mesh 97 Creating the Boundary 97 Creating an Algebraic Mesh 100 Editing to Create an Elliptic Mesh 101 Three Element Airfoil Example with a Hyperbolic Structured Mesh 102 Creating Branch Connectors 102 Creating a Hyperbolic Mesh 104 Editing the Hyperbolic Mesh 105 Three Element Airfoil Example with a Hybrid Mesh 106 Creating Element Extensions 106 Creating the Hyperbolic Meshes 107 Extracting to Create Internal Boundaries 108 Creating a Circular Outer Boundary 109 Creating the Unstructured Mesh 109 Editing the Unstructured Mesh 110 Three Element Airfoil Example with a Modified C Mesh 111 Creating the Hyperbolic Meshes Ill Extracting the Downstream Boundaries 112 Creating the Mixing Region Meshes 113 Extractng to Create Internal Boundaries 114 Creating the Circular Outer Boun
97. his mesh to the one created in the proceeding Section 9 3 Three Element Airfoil Example with a Hybrid Mesh You should notice that there are significantly fewer small trian gular cells downstream of the mixing regions Like the last example this unstructured mesh can be edited to meet the internal optimization criteria This is achieved by setting the Maximum Cells equal to 40000 115 Chapter 7 Examples Figure 7 9 A close up of the Hybrid mesh 116 CHAPTER8 Index Symbols Layers JMax 52 Nodes 39 A ADDONCOMMAND macro 73 Algebraic mesh definition 45 Algebraic meshes 45 boundaries 46 control 47 creation 45 Algebraic Elliptic Structrued dialog Maximum Iterations 49 Algebraic Elliptic Structured creating 10 creation 100 Algebraic Elliptic Structured dialog 46 Algebraic Arclength 47 Algebraic Edge Ortho 48 Algebraic Linear 48 Create button 48 50 Elliptic mesh control 48 Elliptic Relaxation 49 Elliptic Laplace 48 Elliptic Orthogonal 49 Elliptic Thomas 48 mesh control 47 mesh control parameters 48 49 Mesh Label 48 49 Orthogonality Relaxation 49 Algebraic Arclength mesh control 47 Algebraic Edge Ortho mesh control 48 Algebraic Linear mesh control 48 Amtec Technical Support 17 Arc area 24 As Is distribution 37 B Boundaries adding lines on Unstructured dialog 59 closed loops in Unstructured meshes 59 coincident mesh points 4 constraints in Hyperbolic Structured meshes 52
98. ic The JMin boundary may consist of one or more other boundary lines which will be con catenated to form a single boundary when the mesh is created The direction of increasing I index on the JMin boundary is determined by the first boundary line selected Boundary lines defining a hyperbolic boundary must be added in the order that they form the boundary Mesh Generator requires that each sequential line section used in the formation of a boundary to share a common node with the previous line section 3 2 1 Specifying Boundaries The boundary lines selected to define the JMin edge are shown by zone numbers in the text fields labeled JMin Line segments may be selected in one of three ways e Jfa line is selected using the Tecplot Selector tool the button next to the JMin text field reads Add Selected Clicking the appropriate button will add this line s zone number to the corresponding text field e If no line is selected the button next to the JMin text field reads Add From List Clicking this button invokes the Add From List dialog with a multi selection list of line segment zone numbers and names One or more of these items are selected in the usual way click Ctrl click or shift click and clicking OK adds the zone numbers of the selected line seg ments to the appropriate text field Zone numbers are added in the increasing order in the text field e The zone numbers of the line segments may be manually entered directly into the
99. irfoil Example with a Hyperbolic Structured Mesh For this example we will use an existing Tecplot file Load the data file TEC90HOME examples meshgen airfoil plt After the file has loaded switch the Tecplot frame mode to 2D and click on the Scatter on the plot layer buttons We are now ready to begin 7 2 1 Creating Branch Connectors The airfoil plt file is made up of 13 zones and is shown in Figure 7 4 Zones one through four define the slat and zones five through ten define the wing Zones 11 through 13 are the flap Hyperbolic mesh generation requires that all zones defining the bound ary be connected In addition when periodic constraints are specified there is an additional 102 7 2 Three Element Airfoil Example with a Hyperbolic Structured Mesh Figure 7 4 An overview of airfoil plt requirement that the zones form a closed loop For our airfoil example the slat and flap are connected to the wing with lines called branch connectors Now we will add the branch connector from the end point of zone 4 to the starting point of zone 10 To do this perform the following steps 1 Using the Tecplot Selector tool select a node near the trailing edge of zone 4 To make vis ibility clearer and selection easier first use the Tecplot zoom tool to zoom in on the area of interest Now select Create Polyline from the Boundary menu this will call up the Polyline dialog 2 On the Polyline Dialog click Select
100. lected Mesh dialog accept all default values and use the Line Label text field to name this boundary smin Click OK Repeat the process creating wmax and wmin for w1 of the wing and fmax and fmin for f1 of the flap 7 4 3 Creating the Mixing Region Meshes We will now use our extractions to form the JMin boundary of three additional hyperbolic meshes used to capture the mixing regions of the airfoil elements To create these meshes per form the following steps 1 On the Mesh Generator main dialog click on the Hide 2D Mesh check box then Redraw With the Selector tool choose zone 1 e1_1 You may want to refer to Figure 7 4 An overview of airfoil plt to see how the boundaries of the airfoil are named From the Boundary menu choose Selected Line Info Note the Min spacing is 0 0005 This is the distance between the first and second node of e1_1 This will be used as the initial cell spacing requirement when the trailing edge hyperbolic mesh is created Check and note the IMin spacings of e2_1 and e3_1 Now click Hide 2D Mesh again to deactivate it then redraw Your hyperbolic surfaces should be visible Use Add From List on the Hyperbolic Structured dialog to enter smax and smin as the JMin boundary Create w2 for the wing by repeating these steps then perform the following steps to cre ate f2 for the flap Use Add From List on the Hyperbolic Structured dialog to enter fmax and fmin
101. menu on the Tecplot menu bar This will resize the elements in the current Tecplot frame so you can see the new boundary in relation to the slat wing and flap 7 3 5 Creating the Unstructured Mesh Now we are ready to create the unstructured mesh To create this mesh perform the following Steps 1 Select Create Unstructured from the Mesh menu Unstructured mesh boundaries must be entered as closed loops For this example there will be a total of four closed loop bound aries This means there will be four entries in the Closed Loop Boundary list 2 On the Unstructured dialog click New Boundary This will enter Incomplete into the Closed Loop Boundary list Now click Add From List In the list presented highlight sb1 sb2 and sb3 the boundaries on the slat then click OK In the Closed Loop Boundaries list Incomplete will have changed to Int Boundary followed by the three zone numbers of the boundaries 3 Click New Boundary and repeat the process adding wb1 wb2 and wb3 the outer bound aries on the wing to your new boundary Repeat the process once more for the outer bound aries on the flap fb1 fb2 and fb3 4 Click New Boundary and this time use Add From List to add zone 29 arcl Once it has been added highlight this in the Closed Loop Boundaries list and click Reverse Direction notice that Int Boundary changes to Ext Boundary 109 Chapter 7 Examples
102. n Raster Sun MicroSystems Incorporated All other product names mentioned herein are trademarks or registered trademarks of their respective owners NOTICE TO U S GOVERNMENT END USERS Use duplication or disclosure by the U S Government is subject to restrictions as set forth in subparagraphs a through d of the Commercial Computer Restricted Rights clause at FAR 52 227 19 when applicable or in subpara graph c 1 i1 of the Rights in Technical Data and Computer Software clause at DFARS 252 227 7013 and or in sim ilar or successor clauses in the DOD or NASA FAR Supplement Contractor manufacturer is Amtec Engineering Inc Post Office Box 3633 Bellevue WA 98009 3633 CHAPTER 1 CHAPTER 2 Contents Getting Started 1 Starting and Stopping Mesh Generator 1 Starting and Stopping on UNIX Systems I Starting and Stopping on Windows Systems 2 Getting Acquainted with Mesh Generator 2 Creating Simple Meshes 3 Mesh Generation 3 Creating the Boundaries 4 Creating the Mesh 9 Modifying and Converting Boundaries and Meshes 11 Modifying Boundaries 12 Modifying Meshes 13 Converting Meshes 14 Saving Your Work 15 Import NURB File 16 Open Project 16 Save Project 16 Mesh Output 16 Macro Files 17 Getting Help in Mesh Generator 17 Creating Boundaries 19 Polylines 19 Line Definition 20 Node Distribution 22 iii Contents CHAPTER 3 Labeling a Polyline 22 Creating a Polyline 23 Circular Arcs 23 Li
103. n be assigned to each mesh you create The Mesh Label text field is located at the bottom of the Algebraic Elliptic Structured dialog you may enter any characters you wish 3 1 7 Creating an Elliptic Structured Mesh As a comparison we will now mesh our blunt body shape with an Elliptic Orthogonal mesh You can see Section 1 4 2 Modifying Meshes for more information on Mesh Generator s mesh modification options To create a Elliptic Orthogonal mesh perform the following steps 1 Click on the existing mesh labeled laplace then go to the Mesh menu From the list click Delete Selected Mesh 49 Chapter 3 Creating Structured Meshes 2 Now we must change the node distribution on the JMin boundaries b1 and b2 Click on a node on b1 with the Tecplot Selector tool Now choose Edit Selected Line from the Bound ary menu The Circular Arc dialog will be called up Click Node Distribution Set Distribu tion to Even Spacing then click OK On the Circular Arc dialog click Replace Close the dialog 3 Using the Tecplot Selector tool click on a node on b2 Choose Edit Selected Line from the Boundary menu The Polyline dialog will be called up Click Node Distribution Set Distri bution to Even Spacing then click OK On the Polyline dialog click Replace Close the dia log 4 From the Mesh menu choose Create Algebraic Elliptic Structured Add boundaries as indi cated b3 for IMin b4 for IMax b1 and b2 for JMin b5 for J
104. n of the arc s origin Used only if HOWSPECIFIED is set to SPECIFYORI GIN X location of the beginning of the arc Y location of the beginning of the arc X location of the end of the arc Used only if HOWSPECIFIED is set to SPECIFYRA DIUS Y location of the end of the arc Used only if HOWSPECIFIED is set to SPECIFYRA DIUS The angle of the arc Used only if HOW SPECIFIED is set to SPECIFYORIGIN The radius of the arc Used only if HOW SPECIFIED is set to SPECIFYRADIUS The method used to distribute points along the path defined by the circular arc If MULTIPLETANH then the RAWDATA sec tion must contain clustering data The number of mesh nodes to distribute along the circular arc If set to TRUE the mesh nodes are distrib uted in the opposite direction of the arc 78 Macro Commands Parameter Syntax TWOSIDED lt boolean gt INITIALSPACING lt double gt FINALSPACING lt double gt Default Notes TRUE Not used for ASIS and EVENSPACING distribution options If FALSE only the ini tial or final node spacing is used set the other to zero If TRUE both initial and final spacing are set 001 The initial node spacing 001 The final node spacing Used only if TWO SIDED is set to TRUE Example 1 Adda 25 node circular arc with default even spacing distribution ADDONCOMMAND Mesh Generator CREATECIRCULARARC ADDONID COMMAND XORIGIN 1 0 YORIG
105. n this dialog there is an option for choosing the mesh file format a multi selection list for picking the zones to include the mesh file and the standard OK Cancel and Help buttons Mesh file formats supported are Tecplot and PLOT3D both ASCII and binary Only two dimensional zones are included in the multi selection list Clicking OK in the Mesh Output dialog calls up the stan dard file output dialog Note Project files that contain Mesh Generator commands will not work as expected when reading into the Tecplot applications which do not have Mesh Generator installed 16 1 6 Macro Files 1 6 Macro Files Another feature which may be useful to you is the ability to record macros in Mesh Generator This creates a record of steps you have taken in your current Tecplot session To record a macro perform the following steps 1 Click File on the Tecplot menu bar not in Mesh Generator and select Macro then Record 2 Name your file and save it as a mcr macro file This will call up the Macro Recorder dialog See Section 26 1 1 Recording Macros in your Tecplot 7 5 User s Manual for more information about this dialog 3 You can stop recording at any time by clicking Stop Recording on the Macro Recorder dia log 4 You can replay your macro recording by selecting the File menu on the Tecplot menu bar selecting Macro and then Play Note Once you begin recording a macro you must not resize your Tecplot work
106. nal parameters RAWDATA lt polylinerawdata gt Create a new mesh line based on a set of control points a polyline The control points define the path along which mesh nodes are distributed These control points must be specified in the RAWDATA section See 6 5 Raw Data on page 95 for a description of lt polylinerawdata gt Optional Parameters Parameter Syntax Default Notes REPLACEZONE LABEL lt integer gt 0 Zone to replace with the generated line If 0 a new line is created lt string gt n The zone title to apply to the created line 75 Chapter 6 Extended Macros Parameter Syntax INDEXSTART lt integer gt INDEXEND lt integer gt DISTRIBUTION lt distributionoption gt NUMBEROFNODES lt integer gt REVERSELINEDIRECTION lt boolean gt TWOSIDED lt boolean gt INITIALSPACING lt double gt FINALSPACING lt double gt INTERPOLATION lt interpolationoption gt Default 1 ASIS number of control points FALSE TRUE 001 001 CUBIC Notes The control point index at which to begin distrib uting mesh nodes The control point index at which to cease distrib uting mesh nodes 0 indicates the final control point The method used to distribute points along the path defined by the control points ASIS uses the control points themselves If MULTIPLETANH then the RAWDATA section must contain cluster ing data The number
107. nction with the Add Selected buttons Add From List will read Add Selected when using the Selector tool You should enter the values in clockwise starting at the lower edge of the flap the beginning of zone 1 The order of all the zones as entered clockwise is 1 2 3 and 4 3 In the Mesh Control area of the Hyperbolic Structured dialog set Total Distance to 0 006 Accept all other default values then use the Mesh Label text field to name this boundary s1 Click Create The Working dialog will appear while the mesh is generated 4 Now use the Enter Mesh Boundary Zone Numbers text field to enter the zones of the wing as the JMin boundary Entered clockwise these should be 5 6 7 8 9 and 10 111 Chapter 7 Examples 5 In Mesh Control set Total Distance to 0 006 Accept all other default values then use the Mesh Label text field to name this boundary w1 Click Create The Working dialog will appear while your second mesh is generated 6 Now enter the zones of the flap as your JMin boundary Entered clockwise these should be 11 12 and 13 7 Inthe Mesh Control area set Total Distance to 0 006 Accept all other default values then use the Mesh Label text field to name this boundary f1 Click Create The Working dialog will appear while your third mesh is generated Close the Hyperbolic Structured dialog 7 4 2 Extracting the Downstream Boundaries The downstream edges of each of the hyperbolic me
108. ndary menu 2 1 1 Line Definition The Line Definition area of the Polyline dialog is where control points are entered for the polyline you wish to create On the left of this dialog is a list labeled Control Points When you are first defining a new polyline boundary this list will be empty The list will expand as you add control points 2 1 1 1 Entering Control Points To the right of the Control Points list are two text fields labeled X and Y These are the X and Y coordinate text fields where you can enter a new control point or edit an existing control point Next to the X and Y text fields is the Select Endpt button which is active only when a bound ary line is selected in the current Tecplot frame This button allows you to automatically enter the coordinates of the end point closest to a node selected with the Tecplot Selector tool This allows an exact specification of a given end point without having to manually enter the values It avoids mismatch errors which can create problems when attempting to combine the multiple boundaries of a mesh 20 2 1 Polylines Polyline x Line Definition Control Points k Y ci fo Select endue Reo abe Insert Before onret Emwine enmet Insert After inser Ster WEEE Start End Index hix Mode Distribution Line Label Create Relate Close Help Figure 2 2 The Polyline dialog After coordinates have been entered into the X and Y text
109. ne Definition 24 Node Distribution 25 Labeling a Circular Arc Boundary 25 Creating a Circular Arc Boundary 25 Conic Arcs 25 Line Definition 25 Node Distribution 27 Labeling a Conic Arc Boundary 27 Creating a Conic Arc Boundary 27 Importing Boundary Files 29 Loading Tecplot Data Files 29 Importing NURB Files 30 Creating New Boundaries from Existing Boundaries Creating Boundary Lines from Existing Lines 31 Labeling the Boundary 32 Creating the Boundary 32 Extracting New Boundaries 33 Extracting from a Selected Line 33 Labeling the Boundary 35 Creating the Boundary 35 Extracting from a Selected Mesh 35 Labeling the Boundary 36 Creating the Boundary 36 Distributing Nodes Along the Boundaries 37 Node Distribution 37 Number of Nodes 38 Node Spacing 39 Interpolation 40 Editing a Selected Line 41 Deleting a Selected Line 42 Displaying Selected Line Information 42 Creating Structured Meshes 45 Creating Algebraic or Elliptic Meshes 45 30 V CHAPTER 4 CHAPTER 5 CHAPTER 6 Specifying Boundaries 46 Algebraic Mesh Control 47 Labeling an Algebraic Structured Mesh 48 Creating an Algebraic Structured Mesh 48 Elliptic Mesh Control 48 Labeling an Elliptic Structured Mesh 49 Creating an Elliptic Structured Mesh 49 Creating Hyperbolic Meshes 51 Specifying Boundaries 51 Hyperbolic Mesh Control 52 Labeling a Hyperbolic Structured Mesh 53 Creating a Hyperbolic Structured Mesh 53 Editing and Deleting Structured Mes
110. ng available constraints However the fourth boundary JMax remains free This method is very fast and robust but because of the free nature of the fourth boundary it may be better suited for meshes used for external flow calculations Unstructured meshes require each boundary to be a closed loop which starts and ends at the same point You can select lines in the current Tecplot frame to be added to a boundary in the boundary list When a boundary is not a closed loop it is labeled as incomplete in the bound ary list Once the user selects all the lines which make up a closed loop it will be shown as either an external or internal boundary on the list More than one boundary may be specified for an unstructured mesh 1 3 2 Creating the Boundaries Algebraic and elliptic meshes are formed from bounding edges identified as Min IMax JMin and JMax corresponding to the minimum and maximum values of the indices for the two fam ilies of lines I and J that define the structure order of the mesh The lines defining these bounding edges are entered into the Algebraic Elliptic mesh generator by referencing their Tecplot zone numbers A minimum of one boundary line is required to define each bounding edge However more than one boundary line may be used To maintain consistency of the mesh points opposing bounding edges must have equal numbers of mesh points Therefore the IMax and IMin edges must both have the same number of mesh points Simila
111. ng the Delete Zone option under the Data menu in Tecplot Instead Mesh Generator zone deletion Delete Selected Line or Delete Selected Mesh should be used We also recommend that while using Mesh Generator all layout and project reading be done from Mesh Generator s Open Project option under the File menu Tec plot s Open Layout option should only be used by first selecting the New Layout option from Tecplot s File menu Without this Tecplot s Open Layout option will create complications in Mesh Generator Chapter 1 Getting Started Mesh Generator creates multi zone IJ ordered structured and finite element unstructured meshes Two dimensional meshes are defined by boundary lines You define the lines and dis tribute the mesh points nodes along them Meshes may be generated using one of the four methods available algebraic elliptic hyper bolic and unstructured Delaunay triangulation Any combination of structured or unstructured meshes may be converted into either unstructured triangular meshes or unstructured rectangu lar meshes during the output operation When a mesh is generated using either algebraic or elliptic methods this surface is defined by selecting lines that form the four boundaries IMin IMax JMin and JMax of the mesh Hyperbolic mesh generation only requires the mesh be defined by selected lines that form one boundary JMin The two side boundaries Min and Max may be restricted by selecti
112. o the text fields on the Circular Arc dialog Accept all other default values then use the Line Label text field to name this circlel Click Create 4 From the Mesh menu select Create Unstructured On the Unstructured dialog click New Boundary then Add From List Add the boundary lines in the following order b1 b2 b4 b5 and b3 Click Reverse Direction 5 Click New Boundary again followed by Add From List Add circle1 to your second bound ary Click Reverse Direction again We have now specified that the boundaries of our blunt body will be the interior boundary for this mesh and our circle will be the exterior bound ary 6 Use the Mesh Label text field to name this unstructured then click Create The resulting mesh is shown in Figure 4 2 62 4 3 Editing and Deleting Unstructured Meshes 12 10 10 5 0 5 10 X Figure 4 2 The Unstructured mesh 63 Chapter 4 Creating Unstructured Meshes 64 cHaPTeERS Exporting Meshes Mesh Generator allows you to save mesh zones you create in PLOT3D format or in an aug mented Tecplot format which contains boundary and inter zone connection information You may specify ASCII or binary You also have the option of combining mesh zones into a single unstructured zone triangular or quadrilateral for use with software which requires purely unstructured meshes 5 1 Selecting the Format
113. of mesh nodes to distribute along the path defined by the control points If set to TRUE the mesh nodes are distributed in the opposite direction of the control points Not used for ASIS and EVENSPACING distribu tion options If FALSE only the initial or final node spacing is used set the other to zero If TRUE both initial and final spacing are set The initial node spacing The final node spacing Used only if TWOSIDED is set to TRUE The method of interpolating between control points for node placement If CUBIC then a free cubic spline is used Example 1 Add a five node polyline with default distribution control points ADDONCOMMAND ADDONID COMMAND RAWDATA Mesh Generator CREATEPOLYLINE Example 2 Add a 25 node polyline with five control points and Macro Commands multiple tanh distribution with two clustering points Note that the number of nodes between the final clustering point and the end of the line is calculated from NUMBEROFNODES ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATEPOLYLINE DISTRIBUTION MULTIPLETANH NUMBEROFNODES 25 RAWDATA N NOFPFPYN PF WD FE OO UL UW uot oO OOO O it Control points 0 0 lo AHB ooo 16 0 Clustering locations 1 0 6 3 Spacing and of segment nodes 0005 5 0005 10 Syntax ADDONCOMMAND CREA TECIRCULARARC ADDONID Mesh Generator COMMAND CREATECIRCULARARC
114. of the arc XEND lt double gt 0 0 X location of the end of the arc YEND lt double gt t Y location of the end of the arc XVERTEX lt double gt I X location of the vertex of the arc YVERTEX lt double gt 1 0 Y location of the vertex of the arc LENGTHRATIO lt double gt 0 5 The ratio of the height of the arc to the height of the vertex above the baseline Macro Commands Parameter Syntax DISTRIBUTION lt distributionoption gt NUMBEROFNODES lt integer gt REVERSELINEDIRECTION lt boolean gt TWOSIDED lt boolean gt INITIALSPACING lt double gt FINALSPACING lt double gt Default EVENS PACING 30 FALSE TRUE 001 001 Notes The method used to distribute points along the path defined by the circular arc If MULTIPLETANH then the RAWDATA sec tion must contain clustering data The number of mesh nodes to distribute along the circular arc If set to TRUE the mesh nodes are distrib uted in the opposite direction of the arc Not used for ASIS and EVENSPACING distribution options If FALSE only the ini tial or final node spacing is used set the other to zero If TRUE both initial and final spacing are set The initial node spacing The final node spacing Used only if TWO SIDED is set to TRUE Example 1 Example 2 Add a 25 node parabolic arc LENGTHRATIO 0 5 with default even spacing distribution ADDONCOMMAND ADDONID
115. of the mesh so that it may be used later e Boundary All boundaries are lines which exist as one dimensional I ordered Tecplot zones with added geometry A user can create and edit boundaries set and distribute the nodes along these boundaries get information about a specific boundary and delete bound aries e Mesh All two dimensional zones are called meshes whether IJ ordered structured or finite element unstructured Meshes may be generated using one of the four methods available algebraic elliptic hyperbolic or unstructured triangulation Meshes may also be modified or deleted e Hide 2D Mesh This check box enables or disables all two dimensional zones Disabling makes selecting a line in the current Tecplot frame easier The main dialog also provides the number of boundary lines and meshes 1 3 Creating Simple Meshes Hesh Generator Ed Fle Boundary Mesh Mesh Generator Entities Boundary Lines 0 2D Wesh 0 Hide 20 Mesh Close Help Figure 1 1 The Mesh Generator main dialog 1 3 Creating Simple Meshes This section will guide you through the creation of a simple mesh in Mesh Generator First it is helpful to have an introduction to the types of meshes which can be created in Mesh Genera tor and the criteria for creating them 1 3 1 Mesh Generation Mesh generation information is stored based on Tecplot zones therefore you are strongly encouraged not to delete any zones by usi
116. og 6 Now click Node Distribution on the Polyline dialog This will call up the Node Distribution dialog shown in Figure 1 4 In the Node Distribution area set the Distribution drop down to Even Spacing Next set Number Of Nodes to 30 Accept all other default values and click OK 7 On the Polyline dialog use the Line Label text field to name this boundary line b2 Click Create The new boundary line will be drawn in your current Tecplot frame Boundary lines b1 and b2 form a blunt body as shown in Figure 1 5 1 3 2 2 Creating the IMin Boundary To create the IMin boundary Min must be coin cident with JMin Perform the following steps 1 3 Creating Simple Meshes Polyline Line Definition Control Points ka T 0 oo Select Endpi Replace Insert Before onver Polling Henmety Insert After meern Ater pelete Start End Index 1 his Mode Distribution Line Label Create Replace Close Help Figure 1 3 The Polyline dialog 1 With your Tecplot Selector tool select a node on b1 near its starting point of 0 0 Click Select Endpt on the Polyline dialog to enter the X and Y values in the Control Points list In this case X and Y will each be shown as 0 Click Insert Before Now manually enter the values 5 0 for X and Y and click Insert After 2 Now click Node Distribution On the Node Distribution dialog set Distribution to Even Spacing Number Of Nodes to
117. or a NURB curve READNURBFILE Used in mesh project files to restore NURB curve based lines CREATEDEFAULTLINEFROMNURB Used in mesh project files to restore NURB curve based lines CREATEELLIPTICSURFACE Creates a mesh zone using an algebraic or elliptic method where all four boundaries of the zone must be specified CREATEHYPERBOLICSURFACE Creates a mesh zone using a hyperbolic method where only the J boundary must be specified CREATEUNSTRUCTUREDSURFACE Fills a region with triangular cells REMOVELAYER Removes the J JMax mesh line from a hyperbolic mesh zone reduc ing the J dimension by one 74 Macro Commands DELETEZONE Deletes an existing boundary line or mesh zone if your other zones are not dependent on it READPROJECTFILE Restores the mesh generation project WRITEPROJECTFILE Saves the current mesh generation project WRITEGRIDFILE Creates a mesh file containing the specified mesh zones 6 3 Macro Commands The syntax and parameters for each of Mesh Generator s macro commands are listed below Items within single angle brackets lt gt s are defined in 6 4 Parameter Assignment Val ues on page 94 Note The COMMAND strings below must be contained on a single line in your macro command file although they appear on multiple lines below Syntax Description CREATEPOLYLINE ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATEPOLYLINE optio
118. ow the Distribution dropdown In it you must specify at least one clustering con trol point the spacing near this point and the number of nodes before this point The clustering point control is similar to the Polyline dialog where the list is for the selection of clustering information The text fields in the Multiple Tanh area are to enter or modify the values and Replace Add and Delete are the available action buttons Both the Initial and Final Spacing as well as at least one clustering spacing is required When only one cluster ing control point is entered the resulting line will have two segments where the clustering will be at both ends as well as at the clustering point e Polynomial One or Two Sided Nodes are distributed with a cubic polynomial for the Two Sided option or a polynomial function in the X coordinate for the One Sided option The default value for Two Sided is Initial and Final Spacing set to 0 001 When One Sided Initial is selected the Initial Spacing is required and the clustering will occur near the starting point of the line When One Sided Final is selected the Final Spacing is required and the clustering will occur near the ending point of the line 2 2 Number of Nodes The number of nodes to be distributed along the created boundary must be specified This value is entered in the Number Of Nodes text field The number of nodes includes the first and last nodes Valid numbers are any integer
119. put dialog After you select your file a one dimensional I ordered Tecplot zone will be created by distributing a default number of evenly spaced nodes along each NURB curve in the file The distribution of mesh points along the NURB curves may be changed by editing the line with the Edit Selected Line option on the Boundary menu 2 5 Creating New Boundaries from Existing Boundaries Mesh Generator allows you to create new boundaries from previously created boundaries or other I ordered zones that may have been imported For example this may be necessary when a new denser mesh is desired for an existing boundary configuration 30 2 5 Creating New Boundaries from Existing Boundaries Read IGES File File Hame Directories OF igs C Tec o BIN Cancel Eg ci E3 Tec Ey bin J ide Drives E E c micron List Files of Type IGES Files igz Network Figure 2 7 The Read IGES dialog 2 5 1 Creating Boundary Lines from Existing Lines This option is activated by first selecting a line in your current Tecplot frame Next click on the Boundary menu then select Create From Selected Line The dialog which appears will depend on what type of boundary you selected Options include e Polyline The Polyline dialog appears and the nodes from the polyline are inserted into the Control Points list You can then perform whatever actions are needed to define your new boundary e Circular Arc
120. rly the JMin and JMax edges must both have an equal number of mesh points 1 3 Creating Simple Meshes Additionally these mesh boundaries must be closed and the following points must be coinci dent e Min 1 and JMin 1 e Min max and JMax 1 e Max max and JMax max e Max 1 and JMin max Under these requirements Min and Max must increase in the same direction and JMin and JMax must increase in the same direction Note When mesh boundaries are created from multiple boundary lines adjacent lines must have coincident mesh points nodes One of these nodes will be automatically removed after the boundary is assembled 1 3 2 1 Creating the JMin Boundary To create the JMin boundary perform the follow ing steps 1 Click on the Boundary menu then select the Create Circular Arc option This will call up the Circular Arc dialog shown in Figure 1 2 The first option in the Line Definition area of the dialog is Specify Here there are options Center Starting Point Arc Angle and Start ing Ending Point Radius Click on the latter 2 In the Arc area of the dialog enter 0 for X and O for Y in the Start text fields and 1 for X and 1 for Y in the End text fields Accept the remaining default values Use the Line Label text field to name this boundary line b1 and click on Create The arc will be created in the current Tecplot frame Close the Circular Arc dialog 3 Now we will add a polyline to the
121. s 59 boundaries 60 closed loop boundaries 59 creating 62 editing 61 external boundaries 60 internal boundaries 60 mesh control 61 Reverse Direction 61 smoothing 61 USERREC 67 and Tecplot ASCII files 67 and Tecplot binary files 67 boudary information 66 DBPATCH 67 IZPLABEL 68 SBPATCH 67 V Vertex 25 124 W Windows closing Mesh Generator 2 loading Mesh Generator 2 Write Mesh File 16 65 WRITEGRIDFILE macro command 92 WRITEPROJECTFILE macro command 92 125
122. s are based on a three element airfoil The first three element airfoil example demonstrates how to use Hyperbolic Structured mesh generation The last three element airfoil examples use hybrid meshes They use hyperbolic meshes to resolve the boundary layer and mixing regions Then the computational domains are linked together with an unstructured mesh 7 1 Two Dimensional Flat Plate Example with a Structured Mesh An overview of the flat plate example is shown in Figure 7 1 To create your flat plate perform the following steps 7 1 1 Creating the Boundary First we will create the circular leading edge which will be the first section of the Min boundary 1 Select Create Circular Arc from the Boundary menu On the Circular Arc dialog set Spec ify to Center Starting Point Arc Angle 2 Enter the following values into the Center Start and Arc Angle text fields For Center use 0 for X and 0 for Y For Start use 5 0e 5 for X and O for Y For Arc Angle use 90 97 Chapter 7 Examples 0 0002 0 000175 0 00015 0 000125 jmaxt 0 0001 gt 7 5E 05 5SE 05 2 5E 05 O jmint 2 5E 05 0 0001 5E 05 O 5E 05 0 0001 0 00015 X Figure 7 1 An overview of the flat plate example 3 Click Node Distribution On the Node Distribution dialog set Distribution to Exponential Number of Nodes to 9 and select One Sided Initial Set Initial Spacing to 8e 6 and Inter polation to Cubic Click
123. s being output as one or two triangular cells To triangulate structured meshes the cells are divided by the shorter of the two cell diagonals This conversion option is useful for boundary layer flow solutions or other singular perturba tion problems where high aspect ratio cells are required A good triangular boundary layer mesh can be generated by producing a structured mesh in the boundary layer region and then converting the mesh to triangular upon output As with the quadrilateral conversion option internal boundaries between converted meshes are eliminated and lines lying on the boundary of the resulting triangular mesh are included as boundary regions in Tecplot mesh files 71 Chapter 5 Exporting Meshes 72 The ADDONCOMMAND Tecplot Macro cHAPTER6 Extended Macros Macro files allow you to automate Tecplot Mesh Generator augments Tecplot s macro com mand language to allow you to access all of its features from within Tecplot macro files This chapter introduces these macro additions and presents some examples Please refer to the Tecplot User s Manual and Reference Manual for a complete description of Tecplot s macro language To create a macro you may have Tecplot record your keystrokes or use a text editor to create a text file containing the macro commands After you have created the macro you may play it using the Play option listed under Macro on Tecplot s File menu or you may invoke it
124. s discussed in Section 2 7 Distributing Nodes Along Bound aries The default Distribution is Even Spacing and default Number Of Nodes is 30 2 3 3 Labeling a Conic Arc Boundary A name can be assigned to each boundary you create This simplifies boundary selection when choosing from a list to create your mesh The Line Label text field is located at the bottom of the Conic Arc dialog you may enter any characters you wish 2 3 4 Creating a Conic Arc Boundary The conic arc will be created and displayed in the current Tecplot frame after you click Create button It will be a Tecplot I ordered zone After clicking Create the Conic Arc dialog will be reset with its default values To illustrate the creation of boundaries using variations of the options discussed above we will continue the example from section 1 3 2 Creating the Boundaries Perform the following Steps 1 Click on the Boundary menu then select Create Polyline This will call up the Polyline dia log 2 On the dialog enter the coordinates 5 for X and 0 for Y then click Insert Before 3 Use the Tecplot Selector tool to select boundary b2 near the end point Only the Polyline dialog click Select Endpt then click Insert After At this point there should be two points in the Control Point list 5 0 and 5 1 4 Click Node Distribution which calls up the Node Distribution dialog On the dialog set Distribution to Even Spacing and Number Of Nodes to 20
125. se dialogs can now be edited A new boundary will replaced the selection and will be displayed in the current Tecplot frame after you click Replace The dialog will then be reset with its default values 2 9 Deleting a Selected Line To delete a line you have selected click Delete Selected Line from the Boundary menu The selected line will only be deleted if it is not used in other zones otherwise an error message will be displayed 2 10 Displaying Selected Line Information Clicking Selected Line Info accessed from the Boundary menu will call up the Line Info dialog This is shown in Figure 2 12 Selected information about a boundary you have selected in the current Tecplot frame is dis played here The Line Info dialog lists zone number the user or system defined label and type of boundary such as polyline or circular arc It also lists the number of control points the start ing and ending node indices the number of the currently selected node total number of nodes and IMin and IMax spacing IMin spacing reports the distance between the boundary s first and second node Max spacing reports the distance between the last and second to last nodes of the boundary 42 2 10 Displaying Selected Line Information Figure 2 12 The Selected Line Info dialog 43 Chapter 2 Creating Boundaries 44 cHaPTER3 Creating Structured Meshes Mesh Generator features three methods of generating structured
126. shes you have created will be used to form the JMin boundaries for the hyperbolic mesh extensions to each airfoil element For reference see Figure 7 8 which gives an overview of the hyperbolic meshes and their extracted boundary lines s2 gt jmax sb s f2 gt imin fa f1 gt jmax fd j J f2 jmax fb f2 gt imax fc s2 gt imin sa s1 gt jmax sd Slat Flap w2 gt imin wa w2 jmax wb w2 gt imax wc w1 gt jmax wd Wing Figure 7 8 An overview of the hyperbolic meshes and their extracted boundary lines These outer boundaries need to be explicitly defined This is done by creating two sub zones from each of the hyperbolic meshes To create these sub zones perform the following steps 112 7 4 Three Element Airfoil Example with a Modified C Mesh With the Tecplot Selector tool select s1 Now select Extract From Selected Mesh from the Boundary menu This calls up the Extract Selected Mesh dialog In the Line Definition area of the Extract Selected Mesh dialog set Boundary Line to Max Line Set Start to mx and End to 1 By starting at Mx and ending at we are in effect revers ing the line direction Use the Line Label text field to name this boundary smax then click OK The Warning dialog will appear click OK With the Tecplot Selector tool select s1 again Now select Extract From Selected Mesh from the Boundary menu This will call up the Extract Selected Mesh dialog again On the Extract Se
127. space or you will cause an error in your recording and be unable to play it back later Macro files that contain Mesh Generator commands will not work as expected in Tecplot applications which do not have Mesh Generator installed 1 7 Getting Help in Mesh Generator Mesh Generator features an on line help system which is integrated into the interface Help 1s always available by clicking the Help button in any of the Mesh Generator dialogs Help is also available from 6 30 a m to 5 00 p m Pacific Standard Time from Technical Support at 425 653 9393 You can also send e mail to support amtec com with your support questions 17 Chapter 1 Getting Started 18 cHaPTeR2 Creating Boundaries This chapter discusses creating and editing the boundaries for your mesh Boundaries are the lines used to define the sides or edges of your mesh It is not necessary for each boundary line to completely define a mesh since they can be combined at the time the mesh is created This gives you the flexibility to create the mesh boundaries in sections Each created boundary line exists as a Tecplot one dimensional I ordered zone and can be uniquely labeled for easy iden tification Mesh Generator features several options for creating boundary lines By selecting the Bound ary menu you will display these options as shown in Figure 2 1 You can create boundary lines from simple geometries such as polylines circular arcs and coni
128. t Notes INDEXSTART lt integer gt 1 The source zone index at which to begin the extraction INDEXEND lt integer gt 0 The source zone node index at which to ter Example 1 Example 2 minate the extraction 0 indicates the maxi mum index value and negative numbers indicate values less than the maximum index e g 1 gives IMAX Extract nodes 2 to IMAX 1 from zone 1 a line ADDONCOMMAND ADDONID Mesh Generator COMMAND EXTRACTLINE INDEXSTART 2 INDEXEND 1 Extract all nodes from the JMAX boundary of zone 5 a surface ADDONCOMMAND ADDONID Mesh Generator COMMAND EXTRACTLINE SOURCEZONE 5 BOUNDARYLINE JMAX CREATELINESFROMNURBFILE Syntax Description Example ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATELINESFROMNURBFILE lt string gt fa Create mesh lines from IGES NURB curves in a file The string must contain one file name which should be a valid IGES ASCII file Create mesh lines from file airfoil igs ADDONCOMMAND ADDONID Mesh Generator COMMAND CREATELINESFROMNURBFILE airfoil igs 83 Chapter 6 Extended Macros EDITLINEFROMNURBCURVE Syntax ADDONCOMMAND ADDONID Mesh Generator COMMAND EDITLINEFROMNURBCURVE REPLACEZONE lt integer gt optional parameters RAWDATA lt clusteringrawdata gt Description Edit an existing mesh line whose nodes are distributed along a
129. t body with parabolic outer boundary 2 6 Extracting New Boundaries Mesh Generator allows you to extract a new boundary from an existing line I ordered zone or mesh IJ ordered zone These may be previously created boundaries or meshes or they may be zones which were loaded into Tecplot How you extract a new boundary will depend upon whether you have selected a line or a mesh 2 6 1 Extracting from a Selected Line This option is activated by selecting a line in your current Tecplot frame This will then be used for extracting the new boundary Under the Boundary menu select Extract From Selected Line This will call up the Extract Selected Line dialog as shown in Figure 2 9 33 Chapter 2 Creating Boundaries Extract Selected Line x Line Definition otart End Index E Line Label b3 OK Cancel Help Figure 2 9 The Extract Selected Line dialog In the Line Definition area of the dialog you must specify the starting and ending indices of the selected line which are to be extracted to create your new boundary These indices are entered into the Start and End text fields No node distribution changes are allowed when extracting Therefore the only editing permitted on an extracted line is modification of the starting and ending indices Valid values for both starting and ending indices are from 1 to maximum number of nodes on the selected line Note You are allowed to reverse line direction You may
130. the mesh to be nearly orthogonal near the walls Selecting this method requires the Maximum Itera tions Elliptic Relaxation and Orthogonality Relaxation parameters When any of the three elliptic control options are selected the initial mesh will be created using the Algebraic Arclength option The parameters in the Mesh Control area of the Algebraic Elliptic Structured dialog are Maximum Iterations Specifies the maximum number of elliptic iterations to perform for mesh generation Elliptic Relaxation Specifies the relaxation factor for the successive over relaxation SOR method of solving Poisson s equation Increasing this parameter will improve the rate at which the iterative SOR converges However it may also make it less stable Decreasing this parameter makes the relaxation more stable but reduces the convergence rate When the elliptic iteration is unstable it is common to reduce this parameter Orthogonality Relaxation A normalized distance I divided by Max and J divided by JMax where the orthogonality condition is relaxed to ten percent of its value at the bound ary This condition is applied to both the I and J directions The lower the value is the larger the region of equi spacing in the middle of the mesh If this value is too small for example 0 01 the elliptic solver may be less stable due to large gradients in the control function near the boundaries 3 1 6 Labeling an Elliptic Structured Mesh A name ca
131. ti zone formats If more than one mesh is being output the multi zone format is used For single zone output you will be prompted to choose single or multi zone format Unlike the Tecplot format the PLOT3D format does not support structured and unstructured meshes in the same mesh file Attempting to write such a hybrid mesh file will result in an error Binary PLOTS3D files are written using FORTRAN records FORM UNFORMATTED so that they are readable by FORTRAN flow solvers The contents of each record is noted in the fol lowing sections 68 5 2 Mesh Conversion 5 1 2 1 The 2D Single Zone Format PLOT3D s two dimensional mesh file format con sists of the I and J zone dimensions of the mesh followed by all of the X coordinates then all of the Y coordinates with the I index moving fastest Binary files contain two records The first record contains the I and J zone dimensions and the second record contains all coordinate data 5 1 2 2 The Unstructured Format PLOT3D s unstructured mesh files contain e Three integers The number of nodes the number of triangles and the number of tetrahe dra e All X coordinates e All Y coordinates e All Z coordinates e The connectivity list for the triangles e An integer flag for each triangle e The connectivity list for the tetrahedra Since Mesh Generator only outputs two dimensional triangular unstructured meshes the Z coordinates will all be zero and th
132. tion 7 Max line on Extract Selected Mesh dialog 36 IMin boundary orientation 6 Min line on Extract Selected Mesh dialog 36 Importing boundary files 29 NURB files 30 Tecplot data 29 Tecplot files 29 Importing NURB File 16 Importing NURB Files 30 Information 42 Initial Spacing 39 on Hyperbolic Structured dialog 52 Insert After button 21 Insert Before button 21 Interpolation area on Node Distribution dialog 40 IZPLABEL 68 J JMax boundary orientation 8 JMax line on Extract Selected Mesh dialog 36 JMin boundary orientation 5 JMin line on Extract Selected Mesh dialog 36 L Laplace equation 48 Length Ratio acceptable values 26 for ellipse 26 for hyperbola 26 for parabola 26 on Conic Arc dialog 26 Line Definition on Circular Arc dialog 24 Line Definition area on Conic Arc dialog 25 on Extract Selected Mesh dialog 36 Line Defintion 20 Specify on Circular Arc dialog 24 Start and End text fields 22 Line Defintion area on Extract From Selected Line dialog 34 Line direction 38 Line Info dialog 42 Line Label on Circular Arc dialog 25 on Conic Arc dialog 27 on Extract From Selected Line dialog 35 on Extract Selected Mesh dialog 36 on Polyline dialog 22 Lines deleting 42 Information 42 M Macro commands CREATECIRCULARARC 77 CREATECONICARC 80 CREATEDEFAULTLINEFROMNURB 86 CREATEELLIPTICSURFACE 87 CREATEHYPERBOLICSURFACE 88 CREATELINESFROMNURBFILE 83 86 CREATEPOLYLINE 75 CREATEUNSTRUCTUREDSURFACE 90 DE
133. tribution dialog will be called up This is discussed in Section 2 7 Distributing Nodes Along Boundaries The default Distribu tion is As Is and default Number Of Nodes is the number of control points available 2 1 3 Labeling a Polyline A name can be assigned to each polyline you create This simplifies boundary definition when choosing from a list to create your mesh The Line Label text field is located at the bottom of the Polyline dialog you may enter any characters you wish 22 2 2 Circular Arcs 2 1 4 Creating a Polyline The new polyline will be created and displayed in the current Tecplot frame after you click Create It will be a Tecplot I ordered zone After clicking Create the Polyline dialog will be reset with its default values 2 2 Circular Arcs Mesh Generator provides three ways to create boundaries using circular arcs To call up the Circular Arc dialog select Boundary from Mesh Generator s menu then select Create Circular Arc The resulting Circular Arc dialog is shown in Figure 2 3 Circular Arc Line Definition Specify l l f Center Starting Point Arc Angle f Starting Ending Point Radius Counter Clockwise Convent ie Geometry AFC Center a Y 0 T Start 1 0 SElECT ENO AE a select Enmdpi End Arc Angle 90 Degrees 1 Radius Mode Distribution Line Label Create Heplarte Close Help Figure 2 3 The Circular Arc dialog
134. y are concatenated to form a single line The direction of increasing index for the boundary is determined by the first line selected Boundary lines defin ing this boundary must be added in the order that they form the boundary Mesh Generator requires each sequential boundary line used in the formation of a boundary to share a common node with a previous line Each boundary must form a closed loop Once the last node of a particular boundary coincides with the first node of the same boundary this boundary is a complete closed loop Boundary lines may no longer be added The direction of the closed loop boundary is important The outer boundary must proceed counter clockwise around the mesh while inner boundaries must be clockwise Mesh Genera tor will determine whether a boundary is external or internal once it is a closed loop An exter nal boundary counter clockwise will have a Ext Boundary label in the list while an internal boundary will have a Int Boundary label 60 4 2 Unstructured Mesh Control Once it is determined whether a boundary is external or internal the direction of the boundary may be reversed by clicking in the Reverse Direction checkbox An external boundary will become internal and vice versa The boundary s label will be changed accordingly To create a mesh with more than one closed loop boundary you may click on the New Bound ary button as many times as desired Boundaries may be added in any or
135. y is constrained to a line of constant X value using the X at that end of the JMin boundary e Y Constant The boundary is constrained to a line of constant Y value using the Y at that end of the JMin boundary e Periodic The end points of the boundary and Max are checked to insure that they are coincident Max Smoothing Passes is a parameter related to an elliptic relaxation performed on each new mesh line Each new line is created by a hyperbolic marching scheme then a second ghost layer is added by reflecting the previous line across the new line The node positions in the new line are then relaxed according to an elliptic equation using the previous layer and the ghost layer as boundaries Max Smoothing Passes indicates the maximum number of relaxation iter ations the generator will use in the relaxation Enter 0 for a purely hyperbolic scheme or a pos itive number to allow relaxation to occur Default value for this parameter is set to be 100 Generally the more convoluted the geometry the larger the number of smoothing passes The node positions in the new line are then relaxed according to an elliptic equation using the pre vious layer and the ghost layer as boundaries The Reverse Marching Direction check box is used to reverse the direction normal of the marching The default direction proceeds to the left of the JMin boundary Selection this option will cause the marching to proceed to the right of the JMin boun
136. your current Tecplot frame Use the Tecplot Selector tool to move the starting point of your new polyline to a point near the trailing edge of the slat Use the adjustor tool to select the down stream end point of your polyline While trying to maintain the polyline s length rotate the down stream end to approximate the angle of the trailing edge Now call up the Polyline dialog by selecting Create Polylines from the Boundary menu Use Tecplot s Selector tool to select your polyline then click Convert Polyline Geometry Insert After on the Polyline dialog This will add the values of your polyline to the Control Points list on the Polyline dialog Now click on the starting point values shown for your polyline in the Control Points list Once highlighted click Delete In the current Tecplot frame click on a node at or near the end of the trailing edge of the slat Once selected go back to the Polyline dialog and click Select Endpt The values for the node at the end of the trailing edge of the slat will be entered into the X and Y text fields on the Polyline dialog Click Insert After The values will be added to the Control Points list and will be labeled Control Point 2 Click Node Distribution On the Node Distribution dialog set Distribution to Tanh Num ber Of Nodes to 21 Initial Spacing to 0 008 and Final Spacing to 0 0005 Accept all other default values and click OK On the Polyline dialog use the Line Label text field to

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