SECTION 1 - General Overview - Analytical Services & Materials
Contents
1. Restart File restart d The restart file s directory restart d contains a set of grid and solution files Each represents an ac tive block and names BlocN q Where is N is the block number in three digit format 001 for example Each of these files has the following segments see Fig 3 N S Variables Ref Conds amp Gas Const s K s Variables Multispecies Boundary Conditions Figure 3 Segments of Restart file e N S 5 conservative variables in plot3d format for each block e Turbulence variables for each block e Species densities for each block Page 9 PAB3D User Manual Analytical Services amp Materials Inc July 2003 e h e Energy ratio e Specific heat ratio y for each block e N S Turbulence model and Species boundary condition variables for each block The first two lines of the restart file are in this form Ngrid idim jdim kdim ib 1 Ngrid 5 Ntrv Nspv Nseq ib 1 Ngrid Nspv where e Ngrid Number of blocks e idim Number of grid points in the I direction e jdim Number of grid points in the J direction kdim Number of grid points in the K direction e Nseq Grid sequence level for each block used in the last solution e Ntrv 2 if two equation model option is utilized e Nspv Number of species variables 3 1 4 Init and user files The syntax of this line is INIT File init d user cont init d specifies initial boundary conditions values p p u p2. 4 A set of generalized harmonic jet boundary condi tions for total pressure and velocity is provided The boundary conditions are implemented as generaliza tion for total and constant values boundary condi tions 22 and 023 respectively The form of the built in oscillatory jet boundary condition for total pressure is pt pt0 1 A cos 2not p Where pt0 is the value steady state When using the 18 boundary condition flag these are the definitions n_x is the area ratio porosity n_y is the platinum pressure ratio to free stream n_z is the bleeding hole angle 20 or 90 e p_s o 1 use bleeding BC similar to the one in NPARK code o 2 use Darcy s Law for porous wall T_s is the location of BL to set total pressure and temperature and Mach number When using 32 boundary condition Spinning Sur face Boundary Condition flag these are the defini tions e nx ny n z is unit vector axis of rota tion Page 26 e Mach is the Mach number Currently Not Used For Future use e X0 YO Z0 are Cartesian coordinates for a point on the axis of rotation e idr Currently Not Used For Future use is the computational direction of the axis of rotation where idr 1 2 amp 3 defines the axis of rotation to bej k or I direction respectively Le idr 1 means axis of rotation is in the J direction idr 2 means axis of rotation is in the K direction idr 3 means axis of rotation is in
3. Acoustic Prediction Method 5 CFD Based Model Mixer Design and Analysis PAB3D has several built in timesaving routines in cluding grid sequencing and customized computer memory requirements that permit the user to quickly obtain a converged solution PAB3D uses advanced turbulence models to determine the Reynolds Stress terms 6 9 in the governing equations There are several state of the art two equation and algebraic Reynolds Stress turbulence models implemented in the PAB3D code PAB3D is also capable of simulat ing different gases species simultaneously for Real Gas simulations The species concentrations are used to evaluate equivalent thermodynamic and viscous parameters in the flow governing equations All sca lar equations turbulence and species concentration are solved uncoupled from the mean flow governing equations This approach keeps the scheme partially implicit with a reduction in computational time The PAB3D code has an option for space marching scheme 10 12 The interface flux in the stream Copyrighted Subject to restrictions on the title page wise direction is determined by separate terms de pending on the quantities on the left upstream and the right downstream sides of the interface The downstream term which is a significant part of any elliptic problem has a value of zero for hyperbolic or supersonic problem and can be ignored without in troducing significant flow solution for parabolic problem
4. By ignoring the downstream dependence terms in the Roe scheme the solver becomes the space marching scheme Under the modified scheme a solution is obtained plane by plane from upstream to downstream by carrying out a sufficient number of implicit iterations in each plane A solu tion for the entire computational domain is estab lished in a single sweep When the space marching option is used for jet flow computations as conditions permit the computer time is less than one twentieth of the time required for obtaining a time marching solution with the same flow condition The error in troduced due to these different solvers is practically indistinguishable PAB3D uses either natural or specified location to transition the flow from laminar to turbulent Turbu lent calculations do not require any special initializa tion procedure for stable computation The code uses a flexible mesh sequencing procedure Typical solu tions will require 800 iterations on a twice coarsened mesh level 400 iterations on a once coarsened mesh level and 200 iterations on the finest mesh level For example 1 000 000 grid points require 25 30 hours using an SGI R10000 195 MHz workstation Advanced turbulence models 3 5 are needed to get accurate representation of the aerodynamic character istic of the dual separate flow nozzles under investi gation PAB3D uses the two equation turbulence model and the more advanced Algebraic Stress Models ASM To com
5. CFL number CFL fmax abs dt 3 3 3 isym controls turbulence stress representation o 1 cell center turbulence stress representa tion o 2 cell face turbulence stress representation required for Algebraic Reynolds Stress models Input Line for Flags The syntax of this statement is igrid iriso inorm kgl kg2 iperfl jkswp impvis 11 1 1 115001 The flags for this input line are igrid iriso inorm kg1 kg2 iperf1 jkswap and impvis They are defined as igrid This option is not used for all the PAB3D gt 2 0 This is the format flag for the grid input file The PRE and PAB3D codes accept only the PLOT3D format igrid 11 o 11 is the PLOT3D Multi block Grid For mat It reads grid header that contains num ber of blocks and dimensions and then reads a single record of floating numbers contain ing x y z for all grid points Irisio This option is not used for all the PAB3D gt 2 0 This is the PLOT3D output file flag The PLOT3D out files have fixed names xiris d is the grid file qiris d is the flow variables file and keiris d is the turbulence quantities file o 0 PLOT3D grid file o 1 PLOT3D grid flow variables and turbu lence quantities files for full grid o 2 PLOT3D flow variables turbulence quantities files for full grid o l same as 1 but for reduced grid o 2same as 2 but for reduced grid Copyrighted Subject to restrictions on the title page July 2003 Analytical Serv
6. any two equation turbulence models at block level allows the use of different flux approximation variables at block level creates Restart files for each sequence level This cuts down the expense in written a full grid re start files for a coarse grid solution calculates the diffusion terms in all three direc tions with the following two exceptions W UPHS upms1 File Applications Preferences Tools Source l1 la Block 2 A o x o This option should only be used with 3 factor or diagonalization approach o I direction is not available for multi species simulation contains independent and in code post processing utility using Dynamic Memory Allo cation maintains a convergence history for each plane when the Space Marching Scheme is used uses less number of I O files compared to other CFD codes sity Boundary Conditions e Blocks Select Al Face Min Yv Select Opposite 5 imn Face Cuts MIJK Limits Cells p j ba sassifji iki fiz kanm Destination Block IJK Limits b J1 gja 9 10 Max v Face Cells b J2 3 ajlo Kijo Kriz Invert Axes CO Adjacent Face Extrapolation Zero Order Constant static values 2 Figure 1 GUI for PAB3D Copyrighted Subject to restrictions on the title page Page 5 PAB3D User Manual Analytical Services amp Materials Inc July 2003 e offer
7. as described in the above sec tions We created a utility program AutoG3d f which is capable of generating the two essential control files for using the PAB3D code user cont and the solver control file tpab3d cont This utility program reads the grid in the PLOT3D format and generates at least 90 of the contents of this control file The user needs to edit these files for boundary condition flags and initial and boundary condition values in the ginit cont segment of the user cont file If you have the source code you need to edit the Make defs make file for the corresponding computer architecture in use The Makefile will cre ate a bin directory in the user home and set all the executable in this directory User needs to add to the set PATH command in the cshre file the path to the bin directory Then the user will generate four executable programs which are completely in dependent of the problem size 1 make AutoG3d 2 make Gibe 3 make Pre2 4 make Post 5 make Pab2 The following are the procedures for producing a solution with the PAB3D code 1 AutoG3d is an interactive program which will generate the following files autog3d cont the solver control file and userx cont you can use it to setup the user cont file 2 Edit and fix these control files with your problem specifications Copyrighted Subject to restrictions on the title page 3 Run the Preprocessing program Pre2 O Pre2 aut
8. factor used only with Sarkar s model e Int o For two equation models it is the lower limit for turbulence intensity Vk Co where Co is the speed of sound o For one equation mode it is the initial value of the Spalart s variable ratio to laminar vis cosity o 0001 for no tripping O 01 for tripping not implemented for the one equation e ut ul is the smallest turbulence to laminar vis cosity ratio o 1 0 for tripping o 1 0 10 for no tripping Table 16 Definitions for icomp Display Definition Pab3D Compressibility icomp no compressibility no compressibility correction factor for the turbulence transport equations 0 Sarker Compressibility correction for the k equation based on Sarker s model 1 Ziemman Compressibility correction for the k equation based on Ziemman s model 2 Ziemman SF Compressibility correction for the k equation based on Ziemman s model for 3 shear flow SF Ziemman BL Compressibility correction for the k equation based on Ziemman s model for 4 boundary layer BL Wilcox Compressibility correction for the k equation based on Wilcox s model 5 Page 22 Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual e ini controls the use of the Algebraic Reynolds Stress Models with the two equation models Stress Model inl see Table 17 e icmu controls the C Coefficient
9. the J direction e omega is the rotational speed of axis of rotation rad sec e ifun Currently Not Used For Future use 4 5 Tran Cont The syntax of this statement is Begin Tran Cont Number of Blocks with Trip Points amp Trip K Int 2 5 0000001E 02 Block Number amp Number of I Planes 1 1 Number of Points for Plane 1 1 Location J K I for the finest grid 8 0 1 Block Number amp Number of I Planes 5 1 Number of Points for Plane 1 1 Location J K I for the finest grid 8 0 1 End Tran Cont This segment of the user cont file controls the trip intensity and the three dimensional location for a certain block The input line nbltr and trpv are defined as e nbltr is the number of blocks with trip turbu lence intensity Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual e trpv is the turbulence intensity at the trip loca tions 01 05 The input line blockn and plann this line is re peated nb1tr times are defined as e blockn is the block number e plann is the number of i planes with trip The input line npplan is the number of trip points in this plane This line is repeated plann times The input line j k and i is the three dimensional trip location for the finest grid in use This line is re peated nnplan times For surface location either use 0 or the maximum value in this direc
10. v p w and e Using the Gibc utility a simple input specification generates this file user cont deals with all the special options avail able in using the PAB3D code see Section 4 The INIT FILE names are ignored in all versions of PAB3D released after 2 0 because in these versions init dand user cont are fixed names 3 1 5 Turbulence Initialization Flag and Generic Solver Specifications The syntax of this statement is nte year F hh mm Page 10 0 97 1 00 00 The variables nte year F hh mm are defined as e nte is the e variable initialization flag where e lt 0 initialization by iterating twice e 0 no e year is the release year of pab3d code 97 e F hh mm o 0 select the hour and minute hh mm 07 21 is 7 am and 21 minutes for the code to stop and write restart file o 1 select the number of hours and minutes clock time For example 19 20 the code will continue running for 19 hours and 20 minutes If hh and mm are all zeros the code will run using the number of iterations specified in the next sections 3 1 6 Zone Check and Factorization Op tions The syntax of the statement is nzone ichk ischeme 112 The variables nzone ichk and isch are defined as e nzone is the number of zones 1 single zone for general multiblock grids e cflscheme ichk see Table 2 e Factorization isch see Table 3 A typical input line has values of 1 1 2 3 1 7 Global Ite
11. widely used by NASA Lang ley Research Center NASA Glenn Research Center NASA Dryden Flight Research Center General Electric GEAE Pratt amp Whitney P amp W and Boe ing for simulating complex aircraft configurations engines and inlets Those simulations require the use of advanced turbulence models Users have used PAB3D to simulate several different three dimensional mixed flow nozzles 6 8 Each of these configurations required around 3 000 000 grid points to resolve 25 diameters downstream from the nozzle exit and included the entire spreading jet in the radial directions The solutions were used for aerodynamic and acoustic prediction Results were in excellent agreement with the experimental data On a single processor SGI R10000 each case required approximately 72 hours of CPU time There are several ways to reduce elapsed time 1 One approach is to use distributed computers or a multiprocessor computer The MPI Message Passing Interface version of PAB3D was used to produce a solution for an equivalent nozzle exhaust problem with CHEVRON noise sup pression device It used 6 HP 9000 computers Page 4 and got a converged solution in approximately 12 hours 2 Another approach is to solve the nozzle less than 500 000 grid points using time marching which requires less than six hours on a single CPU technique followed by using a space marching technique to complete the jet plume solution John H Glenn R
12. 5 is the flag for selecting a flux splitting scheme e Integration irst Table 6 is the solution strategy flag e ivisc Table 7 is the flag for selecting viscous parameters ivisc is defined as a three digit integer IvJvKnv where one value is required for each global set of iterations see ngit Table 4 Definitions for ivfxj Display Definition Pab3D Flux approximation ivixj van Leer 1 van Leer 1 van Leer 2 Modified van Leer 2 S amp W Steggar and Warming 3 Table 5 Definitions for iv lux Display Definition PAB3D Jacobian ivflux van Leer 1 van Leer for inviscid simulations 1 van Leer 2 Modified van Leer 2 Roe Roe recommended for viscous simulation 3 Table 6 Definitions for irst Display Integration Definition PAB3D irst PNS Parabolized Navire Stokes 1 Time Dependent Time Dependent 2 SMS modified Roe s scheme solution Space Marching 3 recommended for supersonic and small pressure gradient subsonic flow problems AIAA Paper 89 2196 Copyrighted Subject to restrictions on the title page Page 13 PAB3D User Manual Analytical Services amp Materials Inc July 2003 e vis the viscous option the I direction e Jv is the viscous option in the J direction e vis the viscous option in the K direction A viscous option of 1 is for thin layer 2 is for cou pled viscosity and 0 is for no viscous simulation Exampl
13. C gam is the fixed ratio of specific heats itreg is the number of iterations to adjust Y Page 20 Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual Section 4 0 User Control File user cont The segments of user cont are given in Table 12 These segments can be in any order within the user cont file They start with Begin and end with End lines 4 1 Ke Cont Input The syntax of this statement is Begin KE Cont ibk ilhg iord dtf itk icomp comp Int ut ul inl icu idmp 2 14 14 0201 1 e 4 0 1000 33 14 0201 1 e 4 0 1000 4314 0201 1 e 4 0 1000 5 14 14 0201 1 e 4 0 1000 End KE Cont This section describes the ke cont segment of the user cont file This file controls the turbulence models flags and parameters The ke cont segment has a one line input for each block where a turbu lence model is specified The following variables are contained in the data line ib ilhg iord dtf itk icomp comp Int ut ul inl icmu ibn 1 14 1 4 0 2 0 1 1 e 4 0 1000 Table 12 Segments of user cont Default Name File Content memo This is a user s segment for MEMO Begin Memo ginit cont Ginit Cont input segment for Gibc program unit 5 Gibc lt user cont Begin be cont Cont input segment for Gibc f program unit 5 Gibc lt user cont Begin Bc tran cont fixed name for turb
14. EEE AE E EA E 27 SECTION 5 0 SOLUTION PROCEDURE esesseseesesoseesosoesescoesossesecoeseecesosseseeocsoeseseseese 29 5 1 MPI PROCEDURE nieee eee eterno Ee er eE e EEEE e EE SE Ea E i T E 29 Page ii Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual Section 1 0 Welcome Welcome to PAB3D User Manual published by Analytical Services amp Materials Incorporated AS amp M PAB3D was developed by Dr Khaled S Abdol Hamid who is currently pursuing his research work at NASA Langley Research Center This man ual is for users of PAB3D v4 0 software We have divided this manual into five 5 Sections and four 4 Appendices Section 2 introduces PAB3D and its salient features including the names and details of Input Output 1 0 files and the latest developments in PAB3D Section 3 describes the contents of Solver Control File We have shown the input lines bold faced and italicized Sample cases follow the content descrip tion As far as possible we have ensured that the variable names precede the values in this section Section 4 describes the contents of User Control File We have shown the input lines bold faced and itali Copyrighted Subject to restrictions on the title page cized As far as possible we have ensured that the variable names precede the values in this section Section 5 describes the Solution Procedure This section d
15. Navier Stokes diffusion terms 222 l Table 8 Definitions for kturb Display Definition PAB3D Viscous Model kturb Laminar Laminar Flow 1 1 Equation Spalart s one equation turbulence model 5 2 Equation Standard k e turbulence model standard C3 1 44 6 2 Equation Modified k e turbulence model Modified Jones and Launder C3 is a 7 JL function of production and dissipation 2 Equation Speziale k e turbulence model based on Speziale et 8 2 Equation Wilcox Wilcox k model 9 2 Equation RNG k e turbulence model based on Renomlization Group theory 10 2 Equation YS k e turbulence model based on Yang Shih model using an new 11 equation ICOMP 94 21 2 Equation JL Jones and Launder C3 1 45 16 Page 14 Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual The following input line describes the orders and limiters applied to each block i order The spatial discretization order flag is defined as in Table 9 Table 9 Definitions for iord Display Definition PAB3D Spacial accuracy iord First order First order 1 Second order Second order 2 Third order Third order 3 Central difference Central difference 4 Spacial accuracy iord The flag for the limiters is defined in Table 10 Table 10 Definitions for i j and k Imt Display Definition PAB3D Limiter i j k lmt Unl
16. PAB3D v4 0 User Manual Document Number AS amp M 0307 PAB3D Analytical Services amp Materials Inc 107 Research Drive Hampton VA 23666 Phone 757 865 7093 Fax 757 865 7309 URL www asm usa com Multi Block CFD Code for Complex Aerodynamic Configurations PAB3D v4 0 User Manual Document Number AS amp M 0105 PAB3D Dr Alaa Elmiligui Senior Scientist AS amp M ANALYTICAL SERVICES amp MATERIALS INC 107 Research Drive Hampton VA 23666 Phone 757 865 7093 Fax 757 865 7309 Printed in the United States of America on July 20 2001 July 2003 Analytical Services amp Materials Inc PAB3D User Manual Table of Contents SECTION 1 0 WELCOME fiisstessloscesecesnatecdcoscetes ousetecichinesecosesceGisessenteossscs se coivevecosesdsseaes 1 SECTION 2 0 GENERAL OVERVIEW incsciccocsssiccccssscsscooscsscesssstescocecsescsctseseccsveceseseseece 3 2 1 INTRODUCTION ocib aun eee ahah as BaP a RE aE TERA Rs 3 2 2 SALIENT FEATURES enion eE E EEEE AEAEE E ET N 4 D2 Taput eerte eea e a a a E eN 6 PAPAA E O L A o seceded Seed Aide E EES EA E dost E E A 6 SECTION 3 0 SOLVER CONTROL FILE TPAB3D CONT sssesssessoessoessoeesoeesoeesoeesse 9 3 1 GENERAL REQUIREMENTS FOR ALL BLOCKS ccccesscceccceesssesscecececeesensnssaeeeeees 9 3 1 1 Header Version Control cccccccccceessscecssssesecssssscecssssescesssssecessrseeeesenss 9 34 2 Geometry fle sss ccctasccei tharos teetaaiastetaeinn ahd dee
17. Services amp Materials Inc PAB3D User Manual Section 3 0 Solver Control File tpab3d cont 3 1 General Requirements for All Blocks In this part of the control file general information such as file names solver scheme specifications number of iterations and global sets are specified A single line label for identification precedes each group of input 3 1 1 Header Version Control This is a subset of 1 50 release of the PAB3D code The syntax is PAB150 3 1 2 Geometry file This is one of the two main unformatted files The syntax is Grid File gpab3d d This geometry file gpab3d d contains the follow ing segments see Fig 2 XYZ Grid PLOT3D Format Database Connectivity Mem Setup Patch Control File PAB3D Control File User Control File Figure 2 Segments of Geometry File e Grid file in PLOT3D format amp Database infor mation e Memory information needed for the future re lease of PAB3D dynamic memory Copyrighted Subject to restrictions on the title page e Patch control file e Last PAB3D solver and user files used in solving the present case 3 1 3 Restart File PAB3Dv1 5 uses a restart file name but PAB3Dv4 0 uses a restart directory name User can specify up to 20 characters for the file directory name If PAB3D is unable to find the restart file it will use the Init File to fill up the dependent variables arrays p pu pv pw and pe The syntax is
18. alue 3 3 4 Input Line for Flags The syntax of this statement is ibc i2d itrp 0 11 The flags ibc i2d and i trp are defined as e ibc is the Riemann s Invarient flag for far field boundary o 0 constant pressure method o 1 constant entropy method e i2dis the topology flag oO three dimensional flow o 1 two dimensional plane flow in the I direction In the example problem given in the Appendix A a 2D option is utilize to cut the computational over head by 20 Additionally we have used the trip ping option to transition to fully turbulent flow see tran cont segment of the user cont descrip tion e itrp is the turbulent tripping flag o Ono tripping oI trip file exists eran cont 3 3 5 Input Line for Flags The syntax of this statement is ivortt istat sigl sigu gam itreg 100 0 0 28 1 4 1 The flags ivort istat sigl sigm gam and itreg are defined as Page 19 PAB3D User Manual Analytical Services amp Materials Inc July 2003 e ivort is the diffusion coefficient in the k and equations o 1 uses turbulent viscosity f C M e o 2 uses C k e and C 09 e istat controls the method used to solve the multi species governing equations o 0 uses the fully upwind scheme o l uses a similar scheme to the one used to solve the governing equations sigl is the lower limit for the algebraic stress variable C sigm is the upper limit for the algebraic stress variable
19. ar point with KI as the plane of symmetry 2 polar IJ half plane po Half plane across a singular polar point with IJ as the plane of 3 lar symmetry JK half plane Half plane across a singular polar point with JK as the plane of symmetry 4 polar Extrapolation First order extrapolation for all the flow variables 6 Constant total This is a subsonic internal inflow engine boundary condition which fixes the 11 values 1 total flow angle and total pressure and temperature Automatically will switch to the Constant pressure boundary condition if the nozzle pressure is higher than the specified total pressure Constant pressure This is usually used for subsonic exit boundary condition However it will 14 1 switch to Extrapolation condition for each cell if the flow is supersonic Constant static All the variables are fixed at their static conditions This boundary is used to 12 values 1 simulate supersonic inflow or low pressure gradient subsonic external flow Constant Mach The average Mach is fixed at a constant value for which the 25 2 pressure is adjusted to satisfy this boundary condition It is usually used for subsonic inlet boundary condition Periodic Bound It can be used for any periodic boundary plane regardless of the computa 16 ary tional coordinates General symme This is based on the innovative formula provided by Paul and Abdol Hamid 17 try won NASA s Tech Brief of the year 1993 It can be used for any symmetr
20. ary connectivity condition code e k1 is the starting cell index in k e 2 is the ending cell index ink e itis the starting cell index in i e i2s the ending cell index in i Copyrighted Subject to restrictions on the title page In this example face 1 uses 11 engine BC and face 2 communicate with B2 Users can also use in more general way 10021 to assign B2 and F1 as the des tination for B1 and F2 3 2 9 Specification of Cuts for Faces 3 4 In the PAB3D code faces 3 and 4 are the block boundaries atk 1 andk jdim respectively Similar to faces 5 and 6 the specifications are given in two parts First the number of cuts for each of the faces 3 and 4 are given Then the detailed cut speci fications are given consecutively in the order of faces 1 and 2 3 2 10 Number of Cuts for Faces 3 and 4 The variables ncutb 3 and neutb 4 are de fined as the number of cuts for faces 3 and 4 The syntax of this statement is necut Kmin ncut Kmax Kmin amp Kmax Faces 1 1 3 2 11 Boundary Condition Specifications and Range The syntax of this statement is ibcjk j1 j2 il i2 17 18 1 1 01811 The variables ibcji j1 j2 i1 and i2 define the boundary conditions and range for faces 1 and 2 This is a group of repeated specification one for each cut in face 1 then face 2 total number of lines neutb 3 ncutb 4 This is actually a group of lines for all the face cuts The boundary condition code ibcj r
21. block switched off For the space marching solution nitb is the number of iterations per plan I plane e nseq is defined as a three digit integer InJnKn where one value is required for each global set of iterations see ngif e In isthe grid reduction factor in the I direction Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual e Jnis the grid reduction factor in the J direction e Kn is the grid reduction factor in the K direction When the variable nseq 0 it is equivalent to In Jn Kn 1 0r111 full grid Other examples include A grid reduction by a factor of 2in I J K is 222 A grid reduction by a factor of 2 in I J witha full grid count in K is 221 e dt CFL dt of this block if npre1 or when using space marching scheme Dtmb CFL number allowed if npre1 or Order of Magnitude Reduction per plan when using space marching scheme This input line is in very simple form as compared with the last release of the PAB3D code 3 2 Specifications for Each Block 3 2 1 Options for Flux Splitting Schemes Iteration Type Viscosity The syntax of this statement is ivfxj ivflux irst ivisc kturb ibs ibf 1321611 The variables ivfxj ivflux irst ivisc kturb ibs and ibf are defined as e Jacobian ivfxj Table 4 is the flag for a Ja cobian flux splitting scheme e Flux approximation iv 1ux Table
22. ccccecsccescessceesceeeeeeseceeeeeeeeeeneeenes 17 3 2 10 Number of Cuts for Faces 3 and 4 cccccccccccssscccceessecccesseseesesseeeesenss 17 3 2 11 Boundary Condition Specifications and Range ceceecesseeteeseeees 17 3 3 CODE EXECUTION FLAGS INCLUDING SCALE TIMING TRIP ETC 0 0000 18 Sel Witlesame cis csesiieasooks is teiel asad Hos esbeaadeteldeinced saaadethlds ele Satdettastnns setae 18 3 3 2 Input Line for Flags cee cccecsceessecnceceecesecnseeeeceeeecnsecseeseeeseeeeeneeenes 18 3 3 3 Mnput Line Tor Fla gsc ccc cesecccssssctesevesetdeess sabdassavetecves E sahdes T 18 3 3 4 Input Line for Flags iire a E aE EEE NEE 19 3 3 5 Input Line for Fla gs cs meirean i ei i i E beads 19 SECTION 4 0 USER CONTROL FILE USER CONT sscccsssscsssccsssccesssccesscccsscceeees 21 4 1 KE CONT INBU Teo tlie fea lech nthe os ied tne fey Stave konttaee olen Pins a e 21 4 2 SPEC CONT INPUT ienris nns aa AEE ASAAN 23 4 3 GINIT CONT BC CONT INPUT tchiaiessatreriite ratatinleie linet ne 24 4 4 SURF CONT INPU isu noe rE E r A RA O E aa abs E EA E ooee 25 4 5 TRAV CON a elven Med she Soviet tate a eaa a e Salt tcl Solves a NAA 26 4 6 FIMESTEP CONT ciha an aa a N a N R ake 27 Copyrighted Subject to restrictions on the title page Page i PAB3D User Manual Analytical Services amp Materials Inc July 2003 TRACK 2POINT INPUT ocgsccdvsncsstet ceased coed EEE E T A OA 27 4 7 FLOW AXIS CONT o ve deced sea E EEE N EAEE E E
23. currently contains most of the scalar field functions found in Table 1 Important Output File Names and their contents Fixed Name _ File Content resid out restart directory resid out monitors the total residual for the NS and Turbulent transport equations Diag out Within 1 global PAB3D will output the locations of the maximum NS residuals for each block and iteration header dat restart directory header dat Contains control parameters for the specific run Page 6 Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual FAST and PLOT3D with additional support for spa tially varying real gas constant R and ratio of spe cific heats y due to the presence of multiple spe cies The interface is text based with extensive de faults and many shortcuts Batch processing is avail able via automatically generated script files Users can write the results in PLOT3D or binary Tecplot format POST also supports functions that are de fined only on a subset of the domain such as bound ary layer parameters or forces Currently in POST y is the only sub domain function available but in future releases this area will be greatly expanded to provide an engineering toolbox of specialized func tions not usually found in general purpose plotting packages Copyrighted Subject to restrictions on the title page Page 7 July 2003 Analytical
24. e 222 is full Navier Stokes simulation and 111 is thin layer on all three computational directions I J and K Diffusion Terms ivisc Viscous Model kturb Table 8 is the turbulence model flag Most of the two equation k e models are listed in Reference 1 e ibs is the i start cell of that solution e ibf is the i last cell of that solution The variables ibs and ibf represents the restricted range in the I direction 3 2 2 Orders and Limiters in I J K Direc tions ICOND The syntax of this statement is i order i lmt j order j lmt k order k lmt icond 3232320 Table 7 Definitions for ivisc Display Definition PAB3D Diffusion Terms ivisc 000 Inviscid 000 001 K direction Thin Layer diffusion terms 001 010 J direction Thin Layer diffusion terms 010 100 I direction Thin Layer diffusion terms 100 O11 J and K directions Thin Layer diffusion terms O11 101 K and I directions Thin Layer diffusion terms 101 110 I and J directions Thin Layer diffusion terms 110 111 I J and K directions Thin Layer diffusion terms 111 022 J and K directions Coupled diffusion terms 022 202 K and I directions Coupled diffusion terms 202 220 I and J directions Coupled diffusion terms 220 122 I thin with J and K coupled diffusion terms 122 212 J thin with I and K coupled diffusion terms 212 221 K thin with J and I coupled diffusion terms 221 222 Full
25. e information about the grid connectivity and memory The user must create this file 2 restart file s PAB3D will create a directory which contains the information about solution variables and boundary condition 3 init d This file contains the initial conditions which will be created by the user cont section of the User Control File 4 initb d This file contains the boundary condi tions which will be created by the user cont sec tion of the User Control File Users need to create two ASCII solver and user con trol files that will be used to generate at least 75 of the data required to run PAB3D This manual de scribes the options associated with these files 2 2 2 Output The PAB3D output contains many files We have provided the names of important output files and their contents in Table 1 In future versions we will attempt to remove all unwanted output files In this release PAB3D does not have the capability to output files in PLOT3D format However we of fer a post processing utility program POST along with PAB3D to enable users to visualize the results A separate documentation fully describes the func tionality of POST PAB3D users can conveniently view the species concentration and gas property re sults using POST POST can write any PAB3D vari able and many additionally calculated quantities to PLOT3D and binary TECPLOT formats in either cell centered or edge point formats POST
26. e initb d file to set a non uniform flow distribution at each grid point see ginit section Page 16 Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual 3 2 6 Specification of Cuts for Faces 1 2 In the PAB3D code faces 1 and 2 are the block boundaries at j 1 and j jdim respectively Similar to faces 5 and 6 the specifications are given in two parts First the number of cuts for each of the faces 1 2 are given Then the detailed cut specifica tions are given consecutively in the order of faces 1 and 2 3 2 7 Number of Cuts for Faces 1and 2 The variables ncutb 1 andneutb 2 are defined as the number of cuts for faces 1 and 2 The syntax of this statement is necut Jmin ncut Jmax Jmin amp Jmax Faces 1 1 3 2 8 Boundary Condition Specifications and Range The syntax of this statement is ibcjk kl k2 il i2 11 1 80 1 1 218011 The variables ibcj i k1 k2 i1 and i2 define the boundary conditions and range for faces 1 and 2 This is a group of repeated specification one for each cut in face 1 then face 2 total number of lines neutb 1 ncutb 2 This is actually a group of lines for all the face cuts The boundary condition code ibck represents the same set of code numbers given for ibci of faces 5 and 6 For faces 1 and 2 the grid range specifications are given in the order of k1 k2 i1 i2 e ibck is the bound
27. epresents the same set of code numbers given for ibci of faces 5 and 6 For faces 3 and 4 the grid range specifications are given in the order of j1 j2 i1 i2 e ibcj is the boundary connectivity condition code e 41 is the starting cell index inj e 42 is the ending cell index inj Page 17 PAB3 D User Manual Analytical Services amp Materials Inc July 2003 3 3 This i1 is the starting cell index ini i2 is the ending cell index in i Code Execution Flags Including Scale Timing Trip Etc segment of instructions follows all the zone block job control and boundary condition speci fications 3 3 1 Title Line An example of the input line is Rea The 1 Gas Simulation for 2D Nozzle user gives a title to the problem that is being re solved 3 3 The rj 0 0 The 2 Input Line for Flags syntax of this statement is dt iflagts fmax isym 254 30 00 4 50 00 2 flags for this input line are rj dt iflagts fmax and isym They are defined as Page 18 rj is the multiplication factor for x y and z that converts grid units to meters dt is the time step o lt 0 local time step CFL number abs dt o 0 constant time step dt dt smallest time step iflagts is the number of iterations between CFL number adjustment o 0 the code uses local values for calculating time step o lt 0 the code uses stored time step fmax is the maximum adjustment factor of
28. erse the diagonal terms AIAA 87 1113 Scalar Scalar three factor scheme It should give the fastest convergence 4 especially for attached flows This is a block diagonal scheme using LU decomposition to inverse the diagonal terms ngit Isafe Iauto 5 12 The variable ngit is defined as the number of global set of iterations At the end of each global iteration an interim restart file low d is written This fea ture provides a route for periodic examination of per formance parameters and protects the intermediate solutions from being totally lost in case of an abnor mal PAB3D job termination This is particularly im portant for long jobs submitted to the batch queue The Isafe v1 4 option is used with MPI imple mentation PAB3D uses blocking send procedure and either blocking receive Isafe 0 or non blocking receive Isafe 1 The non blocking re ceive produces less communication time between computer nodes However we found that the non blocking option with LAM implementation of MPI does not work with the DEC Alpha computers and we have to use a blocking receive 10 slower Ad ditionally the MPICH implementation of MPI does not yield correct results with non blocking option However the MPICH implementation gives faster Copyrighted Subject to restrictions on the title page message passing time than the LAM 6 1 for both blocking and non blocking options The Iauto is used to distribute blocks to dif
29. escribes the commands needed to execute PAB3D Appendix A provides a description of the real gas models used in PAB3D to calculate Gamma y the ratio of internal energy to local enthalpy Appendix B provides the performance data of PAB3D under a cluster of distributed computers MPI implementation Appendix C describes the procedure for solving an example problem using PAB3D Appendix D provides a bibliography of all the arti cles referred to in developing and implementing various features of the PAB3D code since 1988 Page 1 July 2003 Analytical Services amp Materials Inc PAB3D User Manual Section 2 0 General Overview 2 1 Introduction PAB3D flow solver is widely used in the U S aero space industry for propulsion component design aircraft system analysis and environmental quality studies including jet engine acoustics The solution methodology embodied in the PAB3D code can be applied to a much wider range of problems for gen eral industry and academia as a research tool or a teaching aid The original development and im provement of PAB3D 1 5 was under contracts from the NASA Langley Research Center and the GEAE Company This code has been used to simu late complex aerodynamic flow configurations and is currently being used in several national programs such as 1 High Speed Research HSR 2 Advanced Subsonic Technology AST 3 Large Engine Technology LET 4 CFD Based Aero
30. esearch Center was able to get a space marching solution for an equivalent of 1 000 000 grid points in less than two CPU hours on a 333 MHz Intel PC which is 80 the speed of SGI R10000 195 MHz work station The user may refer to other publications relevant to the usage and or the development of PAB3D 13 64 2 2 Salient Features This manual describes the latest version of the PAB3D code In this version we have attempted to transform PAB3D to be increasingly user friendly We have also reduced the number and size of the files The following are some of the features of the current version v4 0 of PAB3D e allocates memory for the PAB3D and its utilities dynamically through Dynamic Memory Alloca tion routines This feature allows the user to compile the programs only once for each com puter platform also uses a more efficient scaled dynamic memory for distributed computer simulations e allocates temporary memories for the blocks which turned off then releases them when using distributed computing mode e uses first or second order time accurate scheme for unsteady flow simulations e allows the use pf a set of generalized harmonic jet boundary conditions for total pressure and ve locity is provided Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual contains Wilcox K also among other turbu lence models allows the use of
31. f the Spalart s variable ratio to laminar viscos ity Copyrighted Subject to restrictions on the title page o 0001 for no tripping O 01 for tripping not implemented for the one equation e ut ul is the smallest turbulence to laminar viscosity ratio o 1 0 for tripping o 1 0 10 for no tripping e alpha and beta are the flow angles e gam is the thermodynamic constant y e iin controls pr and temp see above 4 4 Surf Cont input This segment of the user cont file complements the ginit d file in prescribing initial boundary condition It has a one line input for each sub face of a block where the boundary condition flag is less than 18 PAB3D uses a new format for Surf section as compared with all the previous PAB3D V lt 3 0 The following variables are contained in the data line iblk iface icut iunit n_x n_y n_Z Mach P_s T_s amp freq phase and ifun e ib1k is the block number e iface is the face number 1 6 e tIunit see Table 18 e nx n y n z isthe unit velocity normal e Mach is the Mach number e p sisstatic e Ts is static temperature e amp is the amplitude 0 to 1 e freq is the frequency Hz e phase is the phase shift deg Page 25 PAB3D User Manual Analytical Services amp Materials Inc July 2003 e ifun 0 Built in harmonic function 1 User function u_pressure_1 2 User function u_pressure_2 2 User function u_pressure_ 3 2 User function u_pressure_
32. ferent computer nodes If Iauto e Q the blocks are distributed by their numbers e the blocks are distributed by their sizes try ing to balance the load to different processors recommended e 2 user specifies load distribution through the use of MPI section in the user cont 3 1 8 Number of Iterations in Each Global Sets The syntax of the statement is nit 10 100 The variable nit is defined as the number of itera tions for ngit sets It is required to specify one value Page 11 PAB3D User Manual Analytical Services amp Materials Inc July 2003 for each global set A typical input can be 10 100 i e 100 iterations for each of the ten global sets The maximum number of iterations allowed per global is 5000 3 1 9 Repeated Specifications for Each Zone and their Blocks In the earlier versions of the PAB3D code the user can divide the grid into multiple zones The multiple zone structure is designed for having multi block multi zone space marching scheme in mind In Fig 4 we show the computational domain of PAB3D In the space marching scheme the multi block structure in each zone is restricted to J K directions only The grid planes must be aligned in the I direction Hence idm is the same for all the blocks in a given zone Kmax Face Imax Face 6 Jmin Face 1 Jmax Face 2 Imin Face 5 Kmin Face 3 Figure 4 PAB3D Computational Domain The general multi block
33. h rc in users home in each of the processors will be used Set path path HOME mpich bin 2 Edit a Pab pg file that assignees the computers as nodes This is a 4 node file cib2 0 aero1l00 1 home hamid bin Pab2 aero4 1 homel hamid bin Pab2 cable 1 home hamid bin Pab2 ln s home hamid bin Pab2 Pab2 mpirun p4pg Pab pg Pab2 The details of MPI implementation are shown in Appendix B This appendix provides details of clus ter performance and test cases Appendix C describes the procedure for solving an example problem Copyrighted Subject to restrictions on the title page
34. ices amp Materials Inc PAB3D User Manual e inorm This option is not used for all the PAB3D gt 2 0 This is the normalization flag for plot3d files variables o 0 output in physical units o 1 non dimensional output e kg1 is the temperature correction flag o 1 no temperature correction for turbulence model o 2 temperature correction for turbulence model research not for production e kg2 is the number of iterations the L U is frozen in using the space marching scheme e iperfi This option is not used for PAB3D versions released after 2 0 is the performance calculation flag o 0 no flow performance calculations o 1 flow performance calculations sent to per out perf track and body track files e 4jkswap is the alternate j k metrics inversion 0 recommended o 0 always j and then k inversion o 1 always j and k alternate o 2 always k and then j inversion e impvis controls the viscous contributions to the implicit terms o l contributions of the viscous terms to the implicit are evaluated recommended during the initial calculations o 0 contributions of the viscous terms to the implicit terms are not evaluated could save 15 20 of the computational time Copyrighted Subject to restrictions on the title page This line will be phased out in the future release of PAB3D No PLOT3D files will be output from PAB3D code and other options will not be available or will have a fixed v
35. imited Unlimited 0 van Albeda van Albeda limiter 1 Minmod minmod limiter 2 Spekereijse Spekereijse Venkate 3 Venkate 1 limiter Spekereijse Modified Spekereijse 4 Venkate 2 Venkate limiter Limiter i lmt j order j lmt k order k lmt The icond flag is defined as e 0 no preconditioning recommended e 1 Model 1 Low Speed Preconditioning e 2 Model 2 Low Speed Preconditioning These models are not fully tested yet 3 2 3 Specification of Cuts in Faces 5 6 In the PAB3D code faces 5 and 6 are the block boundaries ati 1 andi idim respectively Faces 5 and 6 are zonal interfaces in the space marching scheme Therefore their specifications are separated from those of faces 1 2 3 and 4 The specification is done in two steps First the number Copyrighted Subject to restrictions on the title page of cuts on faces 5 and 6 are given in a sub header line containing two integers Second a group of lines listed first for face 5 and then for face 6 specifies the boundary connectivity condition code and the j k range of each cut 3 2 4 Number of Cuts for Faces 5 and 6 The syntax of this statement is necut Imin ncut Imax Imin amp Imax Faces 1 1 The variables ncutpz 5 and ncutpz 6 are defined as the number of cuts for faces 5 and 6 An example input line is 1 1 asingle cut for face 5 and face 6 3 2 5 Boundary Condition Specifications and Range The syntax of this statemen
36. in the cshrc file adding For example Source HOME Lam rc Page 29 PAB3D User Manual Analytical Services amp Materials Inc July 2003 2 Add the Lam rc in users home in each of the processors will be used For example set lam hamid lam set path path HOME lam bin setenv LAMHOME Slam setenv LAMHF77 usr bin 77 3 Edit a Lam host file that assignees the com puters as nodes For example This is a 4 node file cib2 larc nasa gov hamid aerol100 larc nasa gov hamid aero4 larc nasa gov hamid cable larc nasa gov hamid Each computer need to be added to the user s rhosts file User needs to know a minimum of 5 MPI com mands e lamboot Boot and configure the required nodes as lamboot v Lam host e wipe Wipe the configurations as wipe v Lam host e mpirun Run the code in MPI mode as ln s home hamid bin Pab2 Pab2 mpirun c 4 v Pab4 The number of the processors that will be used in this MPI run is 4 The s h is only used if all the nodes can use the same execu Page 30 table otherwise remove the s h If you re move the s h the executable should be lo cated in the any of the directory of the user s path see your cshrc file e mpitask To monitor the tasks in any of the proc essors e lamclean To kill the running MPI job User needs to setup two files to use the MPICH MPI package as follows 1 Change in the cshre file adding Source HOME Ch rc Add the C
37. l Domain In this Tabie 18 Dennitons or iunii segment of user cont the user can specify ini ees Denman na tial boundary condition for different sub faces of a English English mite hance 0 certain block The simple form of this file is auto SI International system units 1 matically generated with the AutoG3d_f utility kg meter etc Page 24 Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual peated neut times where e min is the lower left corner j location e 4max is the upper right corner j location e kmin is the lower left corner k location e kmax is the upper right corner k location e iset is the set number of the boundary condi tion The line nset and iinit is defined as e nset is the number of sets e iinit is the set number used for normalization reference condition The line pr temp mach muT muL alpha beta gam Int and iin are defined as e pr is the first variable where o Reynolds Number unit meter or inch if iin 2 o static pressure if iin 1 o total pressure if iin 0 e temp is the second variable where o total temperature if iin 2 or 0 o sSstatic temperature if iin 1 e mach is the Mach number e Int o For two equation models is the lower limit for turbulence intensity Vk Co where Co is the speed of sound o For one equation mode is the initial value o
38. na TI 9 3 123 Restat Files s 2204 ERA EANA eA cee adel etes deed 9 kA Init and user files cocci ctivsck estes secs ooo saat Sen AAA AE 10 3 1 5 Turbulence Initialization Flag and Generic Solver Specifications 10 3 1 6 Zone Check and Factorization Options c ccccceesecessceseeeeeeeseeeeneeeaes 10 3 1 7 Global Iteration Sets and Number of Processors cccccccccceesssseeeenees 10 3 1 8 Number of Iterations in Each Global Sets 0 cc cc ccccecccceesssececeesseeeeeenes 11 3 1 9 Repeated Specifications for Each Zone and their Blocks eeee 12 3 2 SPECIFICATIONS FOR EACH BLOCK ccccccessesssseseescececeesaececeesaececsesaeeeesesaeeeeneaas 13 3 2 1 Options for Flux Splitting Schemes Iteration Type Viscosity 13 3 2 2 Orders and Limiters in I J K Directions ICOND 0 14 3 2 3 Specification of Cuts in Faces 5 6 ceccesccescesscsssceeseeseeceseeseeeseeeeeneeenes 15 3 2 4 Number of Cuts for Faces 5 and 6 cccccccccsessscecceesssccceesececseseeeesenss 15 3 2 5 Boundary Condition Specifications and Range ccceeseeseetseetteeees 15 3 2 6 Specification of Cuts for Faces 1 2 cceececsccsscesscsesceeeeeeseceeeeeeeeeeeeeenes 17 3 2 7 Number of Cuts for Faces land 2 cccceccccccccessscecsessececeesseeeeeseseeeesenss 17 3 2 8 Boundary Condition Specifications and Range ccceeseesseetteetteeees 17 3 2 9 Specification of Cuts for Faces 3 4 cc
39. nction 3 HR Wilcox High Reynolds model with Wilcox near wall model 4 HR Wall Function High Reynolds model with wall function 5 Copyrighted Subject to restrictions on the title page Page 21 PAB3D User Manual Analytical Services amp Materials Inc July 2003 are defined as Table 15 Definitions for i tk e ib is the block number Display Defititidi P APD Wall itk Boundary e ilhg is the two equation turbulence model op 0 Ez I tion flag p F k u 3 AVE 2 L Wall Integration ilhg see Table 13 H on The most commonly used options for PAB3D are HR LS for internal and flow with solid wall and HR for external flow Most of the Low Reynolds are listed in AIAA Journal Vol 23 No 9 pp 1308 1319 e iorde controls the accuracy of solving the tur bulence model equations Table 14 Definitions for iorde Display Definition Pab3D Spatial iorde Accuracy 1 first order k e solution in I J 1 and K directions 0 k e solution in I J and K direc 0 tions follow the governing equations Spatial Accuracy iorde see Table 14 e atf is the k e CFL number reduction factor 1 e itk is the flag for wall boundary condition for the two equation models Wall Boundary itk see Table 15 e u is dynamic viscosity e icomp is the compressibility model Compressibility icomp see Table 16 e comp is the compressibility correction
40. nd the real gas model 1 in use CO2 N2 and Air are the gases in use for the present simulation The next three lines represent the species mass concentration Each of the lines is equivalent the lines in the ginit cont set Then imodel number which describe the real gas models 0 4 See Appendix A for the description of Table 17 Definitions for in1 Display Definition Pab3D Stress Model inl Linear Basic stress model with linear relation to strain 0 SZL 1 Nonlinear stress model based on modified Shih Zhu and Lumley SZL AIAA 1 95 2246 SZL 2 Nonlinear stress model based on SZL Stress Model NASA TM 106644 1994 2 SSG 1 Nonlinear stress model based on Speziale Sarkar and Gatski SSG stress model 3 with two dimensional assumption SSG 2 Nonlinear stress model based on Speziale Sarkar and Gatski SSG stress model 6 with IIg 0 LRR SSG with Launder Reese and Rodi LRR coefficient for the stress terms 4 GL SSG with Launder Gibson and Launder GL coefficient for the stress terms 5 Girimaji Nonlinear stress model based on Girimaji stress model with two dimensional as sumption Copyrighted Subject to restrictions on the title page Page 23 PAB3D User Manual Analytical Services amp Materials Inc July 2003 the real gas models used in PAB3D code The last number controls the chemical reaction model used by PAB3D Ichem Ichem 0 no chemical reaction Ichem 1 one ste
41. of Viscosity functions o 0 C equals constant o 1 C as function of strain k and based on the Shih and Lumley Model o 2 C as function of strain k and based on the Abid et al Formula e ibn is the blending function between high and low Reynolds Number Models o 0 no blending function o 1 FI blending function o 2 F2 blending function Another example of ke cont is given as follows ib ilhg iord dtf itk icomp comp Int ut ul ikn icmu ibn 3 14 0 4 25 I 1 e 4 0 1 4304 25 1 1 e 4 0 1 7 This example shows that k e turbulence model is used in blocks 3 through 9 in a nine block grid De fault values are used for iord dtf icomp Int ut ul icmu and ibn The ilhg values are cho sen such that e ilhg sets to 14 if there is a wall e ilhg sets to 3 for shear layer flows jet or wake This example also shows that the Girimaji ARSM is used by choosing ikn 7 The value of dt 4 is good for initial iterations at coarser grid levels in some cases For iterations in medium or fine grid the value of dt should be lowered to at 1 if pos sible 4 2 Spec Cont Input The syntax of this statement is Begin Spec Cont 1 0 3 CO2 N2 Air 1 10 temp dat 0 9 0 0 9 0 00 0 1 End Spec Cont 0 1 0 1 0 This segment of the user cont describes the multi species used in the simulation The first number is the Schmidt s Number This is followed by the num ber of species 3 their names a
42. og3d cont will generate tpab3d cont file and modify the input grid file now it is the geometry file The geometry file which contains the grid in formation data base information and mem ory parameters 4 Run Pab2 and get a converge solution Input file iS tpab3d cont and the screen output file is PAB out o Save you restart file for latter recovery O Pab2 and so on until the solution converges through all the possible mesh sequencing steps 5 1 MPI Procedure Simulation of complex aerodynamic problems re quires very large grid order of millions Basically we will need large memory and fast computers to simulate such problems Another alternative is to distribute the problem into smaller and slower com puters The speed of workstation is approaching su per computer speed with a lot of memory This is a continuation of the work started by Dr Fabio during the Summer of 1997 at the ICASE This report ad dresses the implementation of MPI in the PAB3D code This allows the use of distributed computing capability for workstation clusters multiple plat forms using the MPI system Code modification is done using directive command lines This allows us to keep only a single version of the PAB3D code for different platforms for single and distributed capabili ties Appendix D describes briefly the MPI imple mentation and benefits to CFD User needs to setup four files to use the LAM MPI package as follows 1 Change
43. p chemical reaction model for H2O Ichem 2 explicit chemical reaction model Ichem 3 implicit chemical reaction model If Ichem gt 0 PAB3D expect to read a file contains number of reactions species and chemical properties 4 3 Ginit Cont Bc Cont input The Ginit and Bc sections are identical in format User can use Be to specify boundary condition which is different from the initial condition The syn Figure 5 PAB3D Physical Domain tax of this statement is The line iunit nblock and ireg are defined as Begin Ginit Cont iunit nblock ireg 052 Units iunit see Table 18 ncut jmin jmax kmin kmax iset 1 e nblock is the number of computational domain 1 9 1 81 1 blocks 1 1 113 1 81 2 1 Table 19 Definitions for ireg 1 121 1 81 2 Display Definition PAB3D 1 Gas Model ireg 1 121 1 41 3 Ideal Ideal gas model with 0 1 constant gamma for one gas 1 9 1 41 3 Real Multispecies real gas 2 nset iinit Frozen simulation 3 2 pres temp mach Int ut ul alpha beta e ireg is the Real Gas Model flag gamma iin parole L300 0757070 0 0 174 0 Gas Model ireg see Table 19 pres temp mach Int ut ul alpha beta as i 0 20000 1 4 1 The line neut is the number of sub faces describing pres temp mach alpha Int ut ul gamma the boundary condition and is repeated nblock beta iin times jmin jmax kmin kmax and iset are re 14 72 530 0 01 0000 1 4 1 End Ginit Cont Fig 5 shows the PAB3D Physica
44. pare the PAB3D NPARC and WIND codes John H Glenn Research Center recently used algebraic turbulence models to predict multi stream flow characteristic The ASM 5 pro duces the best prediction of jet plume mixing com pared to experimental data and to the standard two equation turbulence models PAB3D is one of the few codes available that uses advanced turbulence models in the simulation of complex compressible three dimensional flows Page 3 PAB3D User Manual Analytical Services amp Materials Inc July 2003 PAB3D requires less memory than most other three dimensional codes The memory requirement for using a two equation turbulence model is less than 23 words grid point There is no additional memory required for the algebraic stress models implemented in the PAB3D code The code speed based on 1 000 000 grid points on a single processor C90 computer varies with the selected solver two factor three factor block and three factor scalar 1 Two factor 17 Us iteration grid point 2 Three factor block 19 us iteration grid point 3 Three factor scalar 7 us iteration grid point The code uses moderate size temporary arrays which are quite efficient on workstations three factor block on SGI R10000 190MHz runs at 110 us iteration grid point Over 50 publications describe the use of the ad vanced turbulence models in the PAB3D code to simulate complex 3D flows see http www asm usa com The code is
45. ration Sets and Number of Processors The syntax of this statement is Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual Table 2 Definitions for ichk Display Definition Pab3D cfl scheme Ichk CFL 0 Don t check for sudden drop density and temperature 0 CFL p Change CFL dt if density p exceeds 50 of the density at the 1 previous time step This is very important option in the first few iterations during the transition from initial condition CFL T Change CFL dt if temperature exceeds 50 of the density at the 2 previous time step This is very important option in the first few iterations during the transition from initial condition CFL p amp T Change CFL dt if density and or temperature could exceed 50 of 3 the density at the previous time step This is very important option in the first few iterations during the transition from initial condition Advances of Flow Simulation Techniques Davis CA 1997 Table 3 Definitions for isch Display Definition Pab3D Factorization isch 2 Factor Two factor scheme This scheme proved to give very fast 2 convergence for supersonic subsonic mixed flows The implicit scheme is restricted to the j k planes AIAA 87 1113 3 Factor Three factor scheme It should give faster convergence especially 3 for full subsonic flows This is a block diagonal scheme using LU decomposition to inv
46. s compatibility with several Operating Sys tem platforms e Unix Computers Cray DEC HP IBM SGI and SUN o Linux Computers DEC and Intel o PCs Win95 98 WinNT and Mac A new program AutoG3d developed by Dr Paul Pao 757 864 3044 at NASA Langley Research Center is now a part of PAB3D This program reads the grid file and generates control and map files with information about patching In addition we have just released a Graphical User Interface GUD called Universal Process Management System UPMS UPMS can be used to generate control files for sev eral CFD codes including PAB3D see Fig 1 To maintain the backward compatibility of PAB3D the control file maintains the following inputs The inputs are active in earlier versions of PAB3D while they remain inactive in the current version l init d user cont PAB3D v4 0 will use fixed name init d and user cont Users do not have to run Ginitmn because we have replaced it with Gibc which is activated by PAB3D 2 Igrid Irisio and inorm PAB3D v4 0 does not use these routines because users can get PLOT3D output using POST 3 iperf1 PAB3D v4 0 does not use this routine because the performance is handled differently using POST 2 2 1 Input The input to PAB3D consists of four 4 unformatted and two 2 ASCII files which the users need to keep in the working directory The four unformatted files are l grid file This file contains all th
47. step The line iblk i j k i_ var is repeated npts times One line for each point to be tracked Each point cor reponds to a variable at a particular point in the com putaion domain Each point is identified by its block number iblk and the i j k location of the point to be tracked i_var is the variable to be tracked Refer to table 20 for i_var definitions Each property to be tracked will have a separate line To track rho and p for the same points iblk i j k i_ var 2 1 60 45 1 2 1 60 45 2 4 7 Flow Axis Cont The syntax of this statement is Begin FlowAxis Cont idr amx amy amz J 1 K 2 I 3 1 1 0 0 End FlowAxis Cont direction of Page 27 PAB3D User Manual Analytical Services amp Materials Inc July 2003 This segment of the user cont files complements idr is the computational direction of axis of rotation ginit d file in prescribing axis of rotation for periodic where idr 1 2 amp 3 defines the axis of rotation to be j boundary condition be 16 The following variables k or I direction respectively are contained in the data line idr amx amy amz amx amy and amz are the direction cosines of axis of rotation for periodic boundary condition Page 28 Copyrighted Subject to restrictions on the title page July 2003 Analytical Services amp Materials Inc PAB3D User Manual Section 5 0 Solution Procedure To start the solution procedure the user needs to pre pare two control files
48. structure in the PAB3D code allows general block connectivity between blocks Each block can have any dimension grid topology and or the spatial orientation of that dimen sion In this case the entire block can be put in one zone For each zone generally in a multi block there is only one zone there are two lines of input number of iterations and block dimensions specifica tions 3 1 9 1 Number of Iterations for Each Zone The syntax of this statement is nitz 10 1 Page 12 The variable nitz is defined as the number of zonal iterations forngit sets where e turns zone on e OQ turns zone off N 1 can be used but it is not necessary see nit 3 1 9 2 Number of Blocks and Block Dimensions The syntax is Block ib Block idim jdim kdim nitb nseq dt dtmb 1 2 9 81 1 444 1 000 0 000 2 2 113 81 1 444 1 000 0 000 3 2 121 81 1 444 1 000 0 000 4 2 121 41 1 444 1 000 0 000 5 2 9 41 1 444 1 000 0 000 This is the input line for the number of blocks and block dimensions ib jdim kdim nitb nseq dt dtmn repeat iblock times for each iblock idim repeat iblock times for each block The variables are defined as e ib block number 5 e idim the number of grid in I direction for a given block e jdim the number of grid in J direction for a given block e kdim the number of grid in K direction for a given block e nitb number of iterations for this block ib nitb 0 it represents the
49. t is ibci jl j2 kl k2 17 1 8 1 80 17 1 8 1 80 The variables ibci j1 j2 k1 and k2 define the boundary conditions and range for faces 5 and 6 This is a group of repeated specifications one for each cut in face 5 and then face 6 total number of lines neutpz 5 ncutpz 6 e ibci is the boundary condition flag Adjacent Boundary normally the block number to which this face is connected However this can be a 10000 series code to prompt the general patched interface In this case the 10000 code format is defined as 10000 the first digit is always 1 It is a flag for general patched interface 10000 the second to fourth digits identify the target block this number is right adjusted E g 10020 is block 2 while 10200 is block 20 10000 the last digit is the face number for the target block that could have a value of 1 2 3 4 5 or 6 A value of 10000 is used to force extrapolation for the empty or undefined cells for any face Page 15 PAB3D User Manual Analytical Services amp Materials Inc July 2003 Table 11 Definitions for ibcijk Display Bound Definition PAB3D ary Condition ibcijk Adjacent Face This is the general patched interface AIAA 95 2336 10000 Noslip Wall Noslip adiabatic wall NASA CR 182032 0 Farfield 1 Characteristic using Riemann Invarients 1 KI half plane Half plane across a singular pol
50. tion If j and k are 0 the code will trip the full j k plane at the i location specified in the previous line 4 6 TimeStep Cont See Time Accurate article unsetady01 pdf The interface to the time accurate features are given as follows Begin TimeStep Cont ir0 ratr ita cfltau ncycle 1 01 2 5 5 ir0 12 norm residual calculations ir0 0 use Q over cells ir0 1 use r over cells ratr is limit the rate of change of all the variables ita positive for physical time sub iteration and nega tive for dual sub iteration cfltau is CFL number for dual time sub iteration ncycle is the number of time retardations per physical time level Copyrighted Subject to restrictions on the title page Track_Point Input Probing or Point tracking is the ability to select points in the computation domain and track selected vari ables in time Output is written to file trackpoint dat located in restart d directory The interface to the point time tracking probing features are given as fol lows Begin Track_Point Cont npts incrmnt 2 1 iblk i j k i_var 2 20 60 45 1 4 25 60 45 5 The first line defines the number of points to be tracked and the incremnet to write to the data file npts incrmnt 2 1 npts is npts is the number of points to be tracked 2 in this case means we are tracking 2 points in time incrmnt is the increment to write to the data file 1 in this case means we are storing data at every time
51. ulence trip location segment Begin Tran Cont surf cont fixed name for special boundary conditions segment Track cont Track Point Probing segment perf cont versions released after V2 0 Performance Specification segment This option is not used for all the Pab3D ke cont Turbulence model specification segment Begin Ke Cont mpi cont Mpi setup for block load balance Begin MPI Cont spec cont Multispecies concentration and setup Begin Spec Cont Table 13 Definitions for ilhg Display Definition Pab3D Wall Integration ilhg LR LS Low Reynolds model of Launder and Sharma 14 HR Abid High Reynolds model with Abid s damping function for dissipation 11 equation LR Yang Low Reynolds model with Yang s damping function 10 LR YS Low Reynolds model with Yang Shih s damping function 8 LR Hamid Low Reynolds model same as LR f 77 with all near wall model terms 7 vanishing away from walls LR NH Low Reynolds model with Nagano Hishida s modification 6 LR Specizal Low Reynolds model with Specizal s damping function 5 LR JL Low Reynolds model of Jones and Launder 4 LR Wall Function LR Reynolds model with wall function 3 LR m Low Reynolds model with damping function f n 2 HR Damping High Reynolds model with damping function 1 HR High Reynolds model with no damping fu
52. y plane in regardless of the computational coordinates It can also be used for slip wall boundary condition Porous wall 2 This bc uses either the bleeding boundary condition similar to the one in 18 NPARC code Porous wall This is a porous flow and constant surface temperature in out normal to the 19 temperature 2 surface Farfield 2 Characteristic using Riemann Invarients 21 Constant total This is a subsonic internal inflow engine boundary condition which fixes the 22 values 2 total flow angle and total pressure and temperature Automatically will switch to the constant pressure boundary condition if the nozzle pressure is higher than the specified total pressure Constant static All the variables are fixed at their static conditions This boundary is used to 23 values 2 simulate supersonic inflow or low pressure gradient subsonic external flow Constant pressure This is usually used for subsonic exit boundary condition However it will 24 2 switch to Extrapolation condition for each cell if the flow is supersonic Constant wall This is to fix constant surface temperature and no slip for wall boundary 30 temperature 2 condition Spinning Wall Sets velocity components on the spinning surface Surface has to be surface 32 of revolution NB PAB3d does not allow for a moving grid Boundary Condition ibcijk Table 11 2 These boundary conditions are specified at the 1 sub face level see surf cont section It reads th
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