TALK=T;RUN( 1, 1)
************************************************************
Q1 created by VDI menu, Version 2025, Date 03/02/25
CPVNAM=VDI; SPPNAM=Core
************************************************************
Echo DISPLAY / USE settings
DISPLAY
This case invloves steady, turbulent flow over a backward-facing
step. The flow is 2d and incompressible. The edge of the step
provides a fixed point of flow separation.
This example uses the low Reynolds form of the Spalart-Allmaras
turbulence model.
The case is based on the NASA validation case
https://turbmodels.larc.nasa.gov/backstep_val.html. The step is
of height h, in a two-dimensional channel of exit width 9h, with
expansion ratio of 1.125. The inlet is at a distance of 110h
upstream of the step, with a fixed-pressure boundary at a
distance 50h downstream of the step.
The Reynolds number based on step height h is 36,000, with
uniform profiles of u and ENTI specified at the inlet. The large
distance upstream of the step allows the boundary layer to fully
develop along the wall before reaching the step.
The model predicts a reattachment length XR/h=6.4, compared with
experimental measurement XR/h=7.1.
//////////////////////// wall ///////////////////////
-----------------------------------------------------
Pressure
Inlet -------> ---------> fixed at
zero
________________
////////////////| Exit
wall /| Recirculation
/| <---- ----->
/|____________________________________
//////////////////////////////////////
wall
ENDDIS
************************************************************
IRUNN = 1 ;LIBREF = 0
************************************************************
Group 1. Run Title
TEXT(Low Reynolds S-A 2D Backward Facing Step)
************************************************************
Group 2. Transience
STEADY = T
************************************************************
Groups 3, 4, 5 Grid Information
* Overall number of cells, RSET(M,NX,NY,NZ,tolerance)
RSET(M,400,265,1)
************************************************************
Group 6. Body-Fitted coordinates
************************************************************
Group 7. Variables: STOREd,SOLVEd,NAMEd
* Non-default variable names
NAME(137)=PRPS ;NAME(138)=STRS
NAME(139)=DVDX ;NAME(140)=DUDY
NAME(141)=CP ;NAME(142)=WDIS
NAME(143)=VOR1 ;NAME(144)=CF
NAME(145)=YPLS ;NAME(148)=DEN1
NAME(149)=EL1 ;NAME(150)=ENUT
* Solved variables list
SOLVE(P1,U1,V1)
* Stored variables list
STORE(ENUT,EL1,DEN1,YPLS,CF,VOR1,WDIS,CP)
STORE(DUDY,DVDX,STRS,PRPS)
* Additional solver options
SOLUTN(P1,Y,Y,Y,N,N,Y)
SOLUTN(U1,Y,Y,Y,N,N,Y)
SOLUTN(V1,Y,Y,Y,N,N,Y)
TURMOD(SPALART-ALLMARAS-LOWRE)
************************************************************
Group 8. Terms & Devices
************************************************************
Group 9. Properties
PRESS0 =1.01325E+05
* Domain material index is 0 signifying:
* Air at 20 deg C, 1 atm, treated as incompressible
SETPRPS(1, 0)
TMP1 = GRND1
TMP1A =300. ;TMP1B =0. ;TMP1C =0.
DVO1DT =3.41E-03
PRT(ENTI)=0.666667
************************************************************
Group 10.Inter-Phase Transfer Processes
************************************************************
Group 11.Initialise Var/Porosity Fields
FIINIT(P1)=0. ;FIINIT(U1)=44.400002
FIINIT(V1)=0.1 ;FIINIT(PRPS)=-1.
FIINIT(WDIS)=1.0E-02 ;FIINIT(ENTI)=1.0E-03
No PATCHes used for this Group
INIADD = F
************************************************************
Group 12. Convection and diffusion adjustments
No PATCHes used for this Group
************************************************************
Group 13. Boundary & Special Sources
No PATCHes used for this Group
EGWF = T
************************************************************
Group 14. Downstream Pressure For PARAB
************************************************************
Group 15. Terminate Sweeps
LSWEEP = 3000
RESFAC =1.0E-04
************************************************************
Group 16. Terminate Iterations
LITER(P1)=200
************************************************************
Group 17. Relaxation
RELAX(P1 ,LINRLX,1. )
RELAX(U1 ,FALSDT,1.0E-03 )
RELAX(V1 ,FALSDT,1.0E-03 )
RELAX(LTLS,LINRLX,1. )
RELAX(ENTI,LINRLX,0.3 )
************************************************************
Group 18. Limits
************************************************************
Group 19. EARTH Calls To GROUND Station
YPLS = T
PARSOL = F
ISG62 = 1
SPEDAT(SET,OUTPUT,NOFIELD,L,T)
SPEDAT(SET,GXMONI,PLOTALL,L,T)
************************************************************
Group 20. Preliminary Printout
DISTIL = T ;NULLPR = F
NDST = 0
DSTTOL =1.0E-02
EX(P1)=107.699997 ;EX(U1)=22.99
EX(V1)=0.4821 ;EX(PRPS)=0.8726
EX(STRS)=0.03026 ;EX(DVDX)=68.970001
EX(DUDY)=3.582E+04 ;EX(CP)=0.08241
EX(WDIS)=7.038E-03 ;EX(VOR1)=3.587E+04
EX(CF)=2.749E-05 ;EX(YPLS)=1.673E-03
EX(LTLS)=2.953E-04 ;EX(ENTI)=1.327E-03
EX(DEN1)=1.038 ;EX(EL1)=0.
EX(ENUT)=1.313E-03
************************************************************
Group 21. Print-out of Variables
WALPRN = T
************************************************************
Echo save-block settings for Group 21
save21begin
* Free-stream velocity
(MAKE of UINF is 0.0 with IF(isweep.eq.fsweep))
(STORE1 of UINF is ABS(U1{1.325,0.05625,0.05}) with swpfin)
(PRINT of UINF is UINF)
* Skin friction coefficient
(STORED of CF is 2*STRS*(ABS(U1)/U1)/(UINF^2) with swpfin)
* Pressure coefficient
(STORED of CP is P1/(0.5*DEN1*UINF^2) with swpfin)
save21end
************************************************************
Group 22. Monitor Print-Out
IXMON = 379 ;IYMON = 177 ;IZMON = 1
NPRMON = 100000
NPRMNT = 1
TSTSWP = -1
************************************************************
Group 23.Field Print-Out & Plot Control
NPRINT = 100000
ISWPRF = 1 ;ISWPRL = 100000
No PATCHes used for this Group
************************************************************
Group 24. Dumps For Restarts
GVIEW(P,-9.99983E-03,0.,0.99995)
GVIEW(UP,0.,1.,0.)
GVIEW(WINDOW,MAX)
GVIEW(DEPTH,1000.)
GVIEW(VDIS,0.962715)
GVIEW(CENTRE,1.,0.05625,0.05)
> DOM, ORIGIN, -1.375000E+00, 0.000000E+00, 0.000000E+00
> DOM, SIZE, 2.000000E+00, 1.125000E-01, 1.000000E-01
> DOM, MONIT, 1.781772E+00, 5.795346E-02, 5.000000E-02
> DOM, SCALE, 1.000000E+00, 1.000000E+00, 1.000000E+00
> DOM, INCREMENT, 1.000000E-02, 1.000000E-02, 1.000000E-02
> GRID, AUTO, F F T
> GRID, RSET_X_1, -150, 1.100000E+00,G
> GRID, RSET_X_2, 250, 1.020000E+00,G
> GRID, RSET_Y_1, -90, 1.100000E+00,G
> GRID, RSET_Y_2, -175, 1.100000E+00,G
> GRID, RSET_Z_1, 1, 1.000000E+00
> DOM, INI_AMB, YES
> DOM, INI_BUOY, YES
> OBJ, NAME, STEP
> OBJ, POSITION, -1.375000E+00, 0.000000E+00, 0.000000E+00
> OBJ, SIZE, 1.375000E+00, 1.250000E-02, 1.000000E-01
> OBJ, GEOMETRY, box
> OBJ, TYPE, BLOCKAGE
> OBJ, MATERIAL, 198,Solid with smooth-wall friction
> OBJ, NAME, INLET
> OBJ, POSITION, -1.375000E+00, 1.250000E-02, 0.000000E+00
> OBJ, SIZE, 0.000000E+00, TO_END, TO_END
> OBJ, DOMCLIP, NO
> OBJ, GEOMETRY, box
> OBJ, TYPE, INLET
> OBJ, PRESSURE, P_AMBIENT
> OBJ, VELOCITY, 44.400002 ,0. ,0.
> OBJ, TURB_IN, VISC_RAT
> OBJ, VISCRAT, 5.000000E+00
> OBJ, NAME, OUT
> OBJ, POSITION, AT_END, 0.000000E+00, 0.000000E+00
> OBJ, SIZE, 0.000000E+00, TO_END, TO_END
> OBJ, DOMCLIP, NO
> OBJ, GEOMETRY, box
> OBJ, TYPE, OUTLET
> OBJ, PRESSURE, P_AMBIENT
> OBJ, COEFFICIENT, 1000.
> OBJ, TURBULENCE, 0. ,7.72E-05
> OBJ, NAME, WALL_UPPER
> OBJ, POSITION, -1.375000E+00, AT_END, 0.000000E+00
> OBJ, SIZE, TO_END, 0.000000E+00, TO_END
> OBJ, DOMCLIP, NO
> OBJ, GEOMETRY, box
> OBJ, TYPE, PLATE
> OBJ, NAME, WALL_LOWER
> OBJ, POSITION, 0.000000E+00, AT_START, 0.000000E+00
> OBJ, SIZE, TO_END, 0.000000E+00, TO_END
> OBJ, DOMCLIP, NO
> OBJ, GEOMETRY, box
> OBJ, TYPE, PLATE
STOP