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Please help: Library case W771: No convergence

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Old   July 27, 2004, 16:50
Default Please help: Library case W771: No convergence
  #1
Alex Costa
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Posts: n/a
Dear Group, I am trying to run the library case W771 with a little bit of modifications. This case is for 1D transient sedimentation. The modifications are: Ending Time: 1.0E+3 Last Time Step : 100 Domain Size in X direction: 3.2E-01 Number of Cells: 100 RHO = 1000 (phase 1) RHO = 2800 (phase 2) Total Number of iterations: 100

The running stops before convergence. I got a message "premature termination" from the RESULT file. Does anybody know How to get the convergence for this case?

Thanks a lot for any answer.

Dr. Alex
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Old   July 27, 2004, 19:47
Default Re: Please help: Library case W771: No convergence
  #2
leon mills
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Alex,

Is there any further information in the result file ? So that I can help in more detail.

Though i have run your exact case, these are my observations from similar problems.

When I have these sorts of problems it is normally that one of the variables (normally pressure - for me)gets too low and the solver can not handle the problem.

I normally look at setting varmin to a more sensible number, and or look at the relaxation factor for that variable.

Hope it helps,

Leon
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Old   July 29, 2004, 10:22
Default Re: Please help: Library case W771: No convergence
  #3
Alex Costa
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Posts: n/a
Dear Leon, Thanks for your advice. I experimented placing for P1: VARMIN =-1.0E+05 VARMAX = 1.0E+05 LINRLX = 1.0E-06

I got premature termination again. That is my result file: (Hopefully there is crucial information I didnt pass to you) ************************************************** **********

---------------------------------------------------------

CCCC HHH PHOENICS Version 3.3.0 - EARTH

CCCCCCCC H (C) Copyright 1999

CCCCCCC See H Concentration Heat and Momentum Ltd

CCCCCCC our new H All rights reserved.

CCCCCC Web-site H Address: Bakery House, 40 High St

CCCCCCC www.cham. H Wimbledon, London, SW19 5AU

CCCCCCC co.uk H Tel: 020-8947-7651

CCCCCCCC H Facsimile: 020-8879-3497

CCCC HHH E-mail: phoenics@cham.co.uk

--------------------------------------------------------- This program forms part of the PHOENICS installation for:

CHAM The code expiry date is the end of : Jun 2011

---------------------------------------------------------

************************************************** **********

Number of F-array locations available is 21000000 Number used before BFC allowance is 10192 Number used after BFC allowance is 10192 ************************************************** ********** Group 1. Run Title and Number ************************************************** ********** ************************************************** **********

TEXT(1-D TRANSIENT SEDIMENTATION :W771)

************************************************** ********** ************************************************** **********

IRUNN = 1 ;LIBREF = 771 ************************************************** ********** Group 2. Transience STEADY = F

* Set overall time and no. of steps TFIRST = 0.000000E+00 ;TLAST = 1.000000E+03 LSTEP = 100 TFRAC ( 1) = 1.000000E-02 ;TFRAC ( 2) = 2.000000E-02 TFRAC ( 3) = 3.000000E-02 ;TFRAC ( 4) = 4.000000E-02 TFRAC ( 5) = 5.000000E-02 ;TFRAC ( 6) = 6.000000E-02 TFRAC ( 7) = 7.000000E-02 ;TFRAC ( 8) = 8.000001E-02 TFRAC ( 9) = 9.000000E-02 ;TFRAC ( 10) = 1.000000E-01 TFRAC ( 11) = 1.100000E-01 ;TFRAC ( 12) = 1.200000E-01 TFRAC ( 13) = 1.300000E-01 ;TFRAC ( 14) = 1.400000E-01 TFRAC ( 15) = 1.500000E-01 ;TFRAC ( 16) = 1.600000E-01 TFRAC ( 17) = 1.700000E-01 ;TFRAC ( 18) = 1.800000E-01 TFRAC ( 19) = 1.900000E-01 ;TFRAC ( 20) = 2.000000E-01 TFRAC ( 21) = 2.100000E-01 ;TFRAC ( 22) = 2.200000E-01 TFRAC ( 23) = 2.300000E-01 ;TFRAC ( 24) = 2.400000E-01 TFRAC ( 25) = 2.500000E-01 ;TFRAC ( 26) = 2.600000E-01 TFRAC ( 27) = 2.700000E-01 ;TFRAC ( 28) = 2.800000E-01 TFRAC ( 29) = 2.900000E-01 ;TFRAC ( 30) = 3.000000E-01 TFRAC ( 31) = 3.100000E-01 ;TFRAC ( 32) = 3.200000E-01 TFRAC ( 33) = 3.300000E-01 ;TFRAC ( 34) = 3.400000E-01 TFRAC ( 35) = 3.500000E-01 ;TFRAC ( 36) = 3.600000E-01 TFRAC ( 37) = 3.700000E-01 ;TFRAC ( 38) = 3.800000E-01 TFRAC ( 39) = 3.900000E-01 ;TFRAC ( 40) = 4.000000E-01 TFRAC ( 41) = 4.100000E-01 ;TFRAC ( 42) = 4.200000E-01 TFRAC ( 43) = 4.300000E-01 ;TFRAC ( 44) = 4.400000E-01 TFRAC ( 45) = 4.500000E-01 ;TFRAC ( 46) = 4.600000E-01 TFRAC ( 47) = 4.700000E-01 ;TFRAC ( 48) = 4.800000E-01 TFRAC ( 49) = 4.900000E-01 ;TFRAC ( 50) = 5.000000E-01 TFRAC ( 51) = 5.100001E-01 ;TFRAC ( 52) = 5.200000E-01 TFRAC ( 53) = 5.300000E-01 ;TFRAC ( 54) = 5.400000E-01 TFRAC ( 55) = 5.500000E-01 ;TFRAC ( 56) = 5.600000E-01 TFRAC ( 57) = 5.700001E-01 ;TFRAC ( 58) = 5.800000E-01 TFRAC ( 59) = 5.900000E-01 ;TFRAC ( 60) = 6.000000E-01 TFRAC ( 61) = 6.100000E-01 ;TFRAC ( 62) = 6.200000E-01 TFRAC ( 63) = 6.300001E-01 ;TFRAC ( 64) = 6.400000E-01 TFRAC ( 65) = 6.500000E-01 ;TFRAC ( 66) = 6.600000E-01 TFRAC ( 67) = 6.700000E-01 ;TFRAC ( 68) = 6.800000E-01 TFRAC ( 69) = 6.900001E-01 ;TFRAC ( 70) = 7.000000E-01 TFRAC ( 71) = 7.100000E-01 ;TFRAC ( 72) = 7.200000E-01 TFRAC ( 73) = 7.300000E-01 ;TFRAC ( 74) = 7.400000E-01 TFRAC ( 75) = 7.500001E-01 ;TFRAC ( 76) = 7.600001E-01 TFRAC ( 77) = 7.700000E-01 ;TFRAC ( 78) = 7.800000E-01 TFRAC ( 79) = 7.900000E-01 ;TFRAC ( 80) = 8.000000E-01 TFRAC ( 81) = 8.100001E-01 ;TFRAC ( 82) = 8.200001E-01 TFRAC ( 83) = 8.300000E-01 ;TFRAC ( 84) = 8.400000E-01 TFRAC ( 85) = 8.500000E-01 ;TFRAC ( 86) = 8.600000E-01 TFRAC ( 87) = 8.700001E-01 ;TFRAC ( 88) = 8.800001E-01 TFRAC ( 89) = 8.900000E-01 ;TFRAC ( 90) = 9.000000E-01 TFRAC ( 91) = 9.100000E-01 ;TFRAC ( 92) = 9.200000E-01 TFRAC ( 93) = 9.300001E-01 ;TFRAC ( 94) = 9.400001E-01 TFRAC ( 95) = 9.500000E-01 ;TFRAC ( 96) = 9.600000E-01 TFRAC ( 97) = 9.700000E-01 ;TFRAC ( 98) = 9.800000E-01 TFRAC ( 99) = 9.900001E-01 ;TFRAC (100) = 1.000000E+00 ************************************************** ********** Group 3. X-Direction Grid Spacing CARTES = T NX = 100 XULAST = 3.200000E-01 XFRAC ( 1) = 1.000000E-02 ;XFRAC ( 2) = 2.000000E-02 XFRAC ( 3) = 3.000000E-02 ;XFRAC ( 4) = 4.000000E-02 XFRAC ( 5) = 5.000000E-02 ;XFRAC ( 6) = 6.000000E-02 XFRAC ( 7) = 7.000000E-02 ;XFRAC ( 8) = 8.000000E-02 XFRAC ( 9) = 9.000000E-02 ;XFRAC ( 10) = 9.999999E-02 XFRAC ( 11) = 1.100000E-01 ;XFRAC ( 12) = 1.200000E-01 XFRAC ( 13) = 1.300000E-01 ;XFRAC ( 14) = 1.400000E-01 XFRAC ( 15) = 1.500000E-01 ;XFRAC ( 16) = 1.600000E-01 XFRAC ( 17) = 1.700000E-01 ;XFRAC ( 18) = 1.800000E-01 XFRAC ( 19) = 1.900000E-01 ;XFRAC ( 20) = 2.000000E-01 XFRAC ( 21) = 2.100000E-01 ;XFRAC ( 22) = 2.200000E-01 XFRAC ( 23) = 2.300000E-01 ;XFRAC ( 24) = 2.400000E-01 XFRAC ( 25) = 2.500000E-01 ;XFRAC ( 26) = 2.600000E-01 XFRAC ( 27) = 2.700000E-01 ;XFRAC ( 28) = 2.800000E-01 XFRAC ( 29) = 2.900000E-01 ;XFRAC ( 30) = 3.000000E-01 XFRAC ( 31) = 3.100000E-01 ;XFRAC ( 32) = 3.200000E-01 XFRAC ( 33) = 3.300000E-01 ;XFRAC ( 34) = 3.400000E-01 XFRAC ( 35) = 3.500000E-01 ;XFRAC ( 36) = 3.600000E-01 XFRAC ( 37) = 3.700000E-01 ;XFRAC ( 38) = 3.800000E-01 XFRAC ( 39) = 3.900000E-01 ;XFRAC ( 40) = 4.000000E-01 XFRAC ( 41) = 4.100000E-01 ;XFRAC ( 42) = 4.200000E-01 XFRAC ( 43) = 4.300000E-01 ;XFRAC ( 44) = 4.400000E-01 XFRAC ( 45) = 4.500000E-01 ;XFRAC ( 46) = 4.600000E-01 XFRAC ( 47) = 4.700000E-01 ;XFRAC ( 48) = 4.800000E-01 XFRAC ( 49) = 4.900000E-01 ;XFRAC ( 50) = 5.000000E-01 XFRAC ( 51) = 5.100000E-01 ;XFRAC ( 52) = 5.200000E-01 XFRAC ( 53) = 5.300000E-01 ;XFRAC ( 54) = 5.400000E-01 XFRAC ( 55) = 5.500000E-01 ;XFRAC ( 56) = 5.600000E-01 XFRAC ( 57) = 5.700000E-01 ;XFRAC ( 58) = 5.800000E-01 XFRAC ( 59) = 5.900000E-01 ;XFRAC ( 60) = 6.000000E-01 XFRAC ( 61) = 6.100000E-01 ;XFRAC ( 62) = 6.199999E-01 XFRAC ( 63) = 6.300000E-01 ;XFRAC ( 64) = 6.400000E-01 XFRAC ( 65) = 6.500000E-01 ;XFRAC ( 66) = 6.600000E-01 XFRAC ( 67) = 6.700000E-01 ;XFRAC ( 68) = 6.799999E-01 XFRAC ( 69) = 6.900000E-01 ;XFRAC ( 70) = 7.000000E-01 XFRAC ( 71) = 7.100000E-01 ;XFRAC ( 72) = 7.200000E-01 XFRAC ( 73) = 7.300000E-01 ;XFRAC ( 74) = 7.400000E-01 XFRAC ( 75) = 7.500000E-01 ;XFRAC ( 76) = 7.600000E-01 XFRAC ( 77) = 7.700000E-01 ;XFRAC ( 78) = 7.800000E-01 XFRAC ( 79) = 7.900000E-01 ;XFRAC ( 80) = 8.000000E-01 XFRAC ( 81) = 8.100000E-01 ;XFRAC ( 82) = 8.200000E-01 XFRAC ( 83) = 8.300000E-01 ;XFRAC ( 84) = 8.400000E-01 XFRAC ( 85) = 8.500000E-01 ;XFRAC ( 86) = 8.600000E-01 XFRAC ( 87) = 8.700000E-01 ;XFRAC ( 88) = 8.800000E-01 XFRAC ( 89) = 8.900000E-01 ;XFRAC ( 90) = 9.000000E-01 XFRAC ( 91) = 9.100000E-01 ;XFRAC ( 92) = 9.200000E-01 XFRAC ( 93) = 9.300000E-01 ;XFRAC ( 94) = 9.400000E-01 XFRAC ( 95) = 9.500000E-01 ;XFRAC ( 96) = 9.600000E-01 XFRAC ( 97) = 9.699999E-01 ;XFRAC ( 98) = 9.800000E-01 XFRAC ( 99) = 9.900000E-01 ;XFRAC (100) = 1.000000E+00 ************************************************** ********** Group 4. Y-Direction Grid Spacing NY = 1 YVLAST = 1.000000E+00 ************************************************** ********** Group 5. Z-Direction Grid Spacing PARAB = F NZ = 1 ZWLAST = 1.000000E+00 ************************************************** ********** Group 6. Body-Fitted Coordinates ************************************************** ********** Group 7. Variables: STOREd,SOLVEd,NAMEd ONEPHS = F EQUVEL = F NAME( 1) =P1 ;NAME( 3) =1U NAME( 4) =2U ;NAME( 9) =R1 NAME( 10) =R2

* Y in SOLUTN argument list denotes:

* 1-stored 2-solved 3-whole-field

* 4-point-by-point 5-explicit 6-harmonic averaging SOLUTN(P1 ,Y,Y,N,N,N,Y) SOLUTN(1U ,Y,Y,N,N,N,Y) SOLUTN(2U ,Y,Y,N,N,N,Y) SOLUTN(R1 ,Y,Y,N,N,N,Y) SOLUTN(R2 ,Y,Y,N,N,N,Y) ************************************************** ********** Group 8. Terms & Devices

* Y in TERMS argument list denotes:

* 1-built-in source 2-convection 3-diffusion 4-transient

* 5-first phase variable 6-interphase transport TERMS (P1 ,Y,Y,Y,N,Y,Y) TERMS (1U ,Y,Y,Y,Y,Y,Y) TERMS (2U ,Y,Y,Y,Y,N,Y) TERMS (R1 ,Y,Y,Y,Y,Y,Y) TERMS (R2 ,Y,Y,Y,Y,N,Y) DIFCUT = 5.000000E-01 ;ZDIFAC = 1.000000E+00 GALA = F ;ADDDIF = F EQDVDP = F ISOLX = -1 ;ISOLY = 0 ;ISOLZ = 0 ************************************************** ********** Group 9. Properties RHO1 = 1.000000E+03 ;TMP1 = 0.000000E+00 EL1 = 0.000000E+00 TSURR = 0.000000E+00 ;TEMP0 = 0.000000E+00 PRESS0 = 0.000000E+00 DVO1DT = 3.330000E-03 RHO2 = 2.830000E+03 ;TMP2 = 0.000000E+00 EL2 = 0.000000E+00 DVO2DT = 0.000000E+00 ENUL = 1.000000E-05 ;ENUT = 0.000000E+00 PHINT (1U ) = -2.022000E+04 ;PHINT (2U ) = -2.022000E+04 PHINT (R1 ) = -2.022000E+04 ;PHINT (R2 ) = -2.022000E+04 PRNDTL(1U ) = 1.000000E+00 ;PRNDTL(2U ) = 1.000000E+00 PRNDTL(R1 ) = 1.000000E+00 ;PRNDTL(R2 ) = 1.000000E+00 PRT (1U ) = 1.000000E+00 ;PRT (2U ) = 1.000000E+00 PRT (R1 ) = 1.000000E+00 ;PRT (R2 ) = 1.000000E+00 CP1 = 1.005000E+03 ;CP2 = 4.181800E+03 ************************************************** ********** Group 10.Inter-Phase Transfer Processes CFIPS = 1.000000E+04 RLOLIM = 0.000000E+00 ;CMDOT = 0.000000E+00 CINT (P1 ) = 1.000000E+00 ;CINT (1U ) = 1.000000E+00 CINT (2U ) = 1.000000E+00 ;CINT (R1 ) = 1.000000E+00 CINT (R2 ) = 1.000000E+00 PHINT (P1 ) = -2.022000E+04 ;PHINT (1U ) = -2.022000E+04 PHINT (2U ) = -2.022000E+04 ;PHINT (R1 ) = -2.022000E+04 PHINT (R2 ) = -2.022000E+04 ************************************************** ********** Group 11.Initialise Var/Porosity Fields FIINIT(P1 ) = 1.000000E-10 ;FIINIT(1U ) = 1.000000E-10 FIINIT(2U ) = 1.000000E-10 ;FIINIT(R1 ) = 5.000000E-01 FIINIT(R2 ) = 5.000000E-01

No PATCHes yet used for this Group INIADD = T FSWEEP = 1 NAMFI =CHAM ************************************************** ********** Group 12. Patchwise adjustment of terms Patches for this group are printed with those for Group 13. Their names begin either with GP12 or & ************************************************** ********** Group 13. Boundary & Special Sources

PATCH(BUOYANCY,PHASEM, 1, 100, 1, 1, 1, 1, 1, 100) COVAL(BUOYANCY,1U , FIXFLU , GRND1 ) COVAL(BUOYANCY,2U , FIXFLU ,-9.810000E+00) XCYCLE = F EGWF = F BUOYA =-9.810000E+00 ; BUOYB = 0.000000E+00 BUOYC = 0.000000E+00 ************************************************** ********** Group 14. Downstream Pressure For PARAB ************************************************** ********** Group 15. Terminate Sweeps LSWEEP = 100 ;ISWC1 = 1 LITHYD = 1 ;LITFLX = 1 ;LITC = 1 ;ITHC1 = 1 ISWR1 = 1 ;ISWR2 = 10000 SELREF = T RESFAC = 1.000000E-03 ************************************************** ********** Group 16. Terminate Iterations LITER (P1 ) = 20 ;LITER (1U ) = 10 LITER (2U ) = 10 ;LITER (R1 ) = 1 LITER (R2 ) = 1 ENDIT (P1 ) = 1.000000E-03 ;ENDIT (1U ) = 1.000000E-03 ENDIT (2U ) = 1.000000E-03 ;ENDIT (R1 ) = 1.000000E-03 ENDIT (R2 ) = 1.000000E-03 ************************************************** ********** Group 17. Relaxation RELAX(P1 ,LINRLX, 1.000000E-06) RELAX(1U ,FALSDT, 1.000000E-01) RELAX(2U ,FALSDT, 1.000000E-01) RELAX(R1 ,LINRLX, 4.000000E-01) RELAX(R2 ,LINRLX, 5.000000E-01) OVRRLX = 0.000000E+00 EXPERT = F ;NNORSL = F ************************************************** ********** Group 18. Limits VARMAX(P1 ) = 1.000000E+05 ;VARMIN(P1 ) =-1.000000E+05 VARMAX(1U ) = 1.000000E+06 ;VARMIN(1U ) =-1.000000E+06 VARMAX(2U ) = 1.000000E+06 ;VARMIN(2U ) =-1.000000E+06 VARMAX(R1 ) = 1.000000E+00 ;VARMIN(R1 ) = 1.000000E-06 VARMAX(R2 ) = 1.000000E+00 ;VARMIN(R2 ) = 1.000000E-06 ************************************************** ********** Group 19. EARTH Calls To GROUND Station USEGRD = T ;USEGRX = T ASAP = T SPEDAT(SET,OBJNAM,^PROFILE,C,PROFILE) SPEDAT(SET,IGESTYPE,^PROFILE,C,USER_DEFINED) ************************************************** ********** Group 20. Preliminary Printout ECHO = T ************************************************** ********** Group 21. Print-out of Variables INIFLD = F ;SUBWGR = F

* Y in OUTPUT argument list denotes:

* 1-field 2-correction-eq. monitor 3-selective dumping

* 4-whole-field residual 5-spot-value table 6-residual table OUTPUT(P1 ,Y,Y,Y,Y,Y,Y) OUTPUT(1U ,Y,Y,Y,Y,Y,Y) OUTPUT(2U ,Y,Y,Y,Y,Y,Y) OUTPUT(R1 ,N,N,N,N,N,N) OUTPUT(R2 ,Y,Y,Y,Y,Y,Y) ************************************************** ********** Group 22. Monitor Print-Out IXMON = 47 ;IYMON = 1 ;IZMON = 1 NPRMON = 100000 ;NPRMNT = 1 ;TSTSWP = 10001 UWATCH = F ;USTEER = F HIGHLO = F ************************************************** ********** Group 23.Field Print-Out & Plot Control NPRINT = 100 ;NUMCLS = 5 NTPRIN = 5 ;ISTPRF = 1 ;ISTPRL = 10000 NXPRIN = 20 ;IXPRF = 1 ;IXPRL = 100 IPLTF = 2 ;IPLTL = 30 ;NPLT = 1 ISWPRF = 1 ;ISWPRL = 100000 ITABL = 3 ;IPROF = 3 ABSIZ = 5.000000E-01 ;ORSIZ = 4.000000E-01 NTZPRF = 1 ;NCOLPF = 50 ICHR = 2 ;NCOLCO = 45 ;NROWCO = 20

Parent VR object for this patch is: PROFILE PATCH(PROFILE ,PROFIL, 1, 100, 1, 1, 1, 1, 1, 10) PLOT(PROFILE ,P1 , 0.000000E+00, 0.000000E+00) PLOT(PROFILE ,1U ,-1.000000E+00,-1.000000E+00) PLOT(PROFILE ,2U ,-1.000000E+00,-1.000000E+00) PLOT(PROFILE ,R1 , 0.000000E+00, 0.000000E+00) ************************************************** ********** Group 24. Dumps For Restarts SAVE = T ;AUTOPS = F ;NOWIPE = T NSAVE =CHAM IDISPA = 1

*** grid-geometry information *** X-coordinates of the cell centres

1.600E-03 4.800E-03 8.000E-03 1.120E-02 1.440E-02

1.760E-02 2.080E-02 2.400E-02 2.720E-02 3.040E-02

3.360E-02 3.680E-02 4.000E-02 4.320E-02 4.640E-02

4.960E-02 5.280E-02 5.600E-02 5.920E-02 6.240E-02

6.560E-02 6.880E-02 7.200E-02 7.520E-02 7.840E-02

8.160E-02 8.480E-02 8.800E-02 9.120E-02 9.440E-02

9.760E-02 1.008E-01 1.040E-01 1.072E-01 1.104E-01

1.136E-01 1.168E-01 1.200E-01 1.232E-01 1.264E-01

1.296E-01 1.328E-01 1.360E-01 1.392E-01 1.424E-01

1.456E-01 1.488E-01 1.520E-01 1.552E-01 1.584E-01

1.616E-01 1.648E-01 1.680E-01 1.712E-01 1.744E-01

1.776E-01 1.808E-01 1.840E-01 1.872E-01 1.904E-01

1.936E-01 1.968E-01 2.000E-01 2.032E-01 2.064E-01

2.096E-01 2.128E-01 2.160E-01 2.192E-01 2.224E-01

2.256E-01 2.288E-01 2.320E-01 2.352E-01 2.384E-01

2.416E-01 2.448E-01 2.480E-01 2.512E-01 2.544E-01

2.576E-01 2.608E-01 2.640E-01 2.672E-01 2.704E-01

2.736E-01 2.768E-01 2.800E-01 2.832E-01 2.864E-01

2.896E-01 2.928E-01 2.960E-01 2.992E-01 3.024E-01

3.056E-01 3.088E-01 3.120E-01 3.152E-01 3.184E-01 Y-coordinates of the cell centres

5.000E-01 Z-coordinates of the cell centres

5.000E-01

X-coordinates of the (higher) cell faces

3.200E-03 6.400E-03 9.600E-03 1.280E-02 1.600E-02

1.920E-02 2.240E-02 2.560E-02 2.880E-02 3.200E-02

3.520E-02 3.840E-02 4.160E-02 4.480E-02 4.800E-02

5.120E-02 5.440E-02 5.760E-02 6.080E-02 6.400E-02

6.720E-02 7.040E-02 7.360E-02 7.680E-02 8.000E-02

8.320E-02 8.640E-02 8.960E-02 9.280E-02 9.600E-02

9.920E-02 1.024E-01 1.056E-01 1.088E-01 1.120E-01

1.152E-01 1.184E-01 1.216E-01 1.248E-01 1.280E-01

1.312E-01 1.344E-01 1.376E-01 1.408E-01 1.440E-01

1.472E-01 1.504E-01 1.536E-01 1.568E-01 1.600E-01

1.632E-01 1.664E-01 1.696E-01 1.728E-01 1.760E-01

1.792E-01 1.824E-01 1.856E-01 1.888E-01 1.920E-01

1.952E-01 1.984E-01 2.016E-01 2.048E-01 2.080E-01

2.112E-01 2.144E-01 2.176E-01 2.208E-01 2.240E-01

2.272E-01 2.304E-01 2.336E-01 2.368E-01 2.400E-01

2.432E-01 2.464E-01 2.496E-01 2.528E-01 2.560E-01

2.592E-01 2.624E-01 2.656E-01 2.688E-01 2.720E-01

2.752E-01 2.784E-01 2.816E-01 2.848E-01 2.880E-01

2.912E-01 2.944E-01 2.976E-01 3.008E-01 3.040E-01

3.072E-01 3.104E-01 3.136E-01 3.168E-01 3.200E-01 Y-coordinates of the (higher) cell faces

1.000E+00 Z-coordinates of the (higher) cell faces

1.000E+00

--- INTEGRATION OF EQUATIONS BEGINS ---

************************************************** ********** TIME STP= 1 SWEEP NO= 100 ZSLAB NO= 1 ITERN NO= 1 TIME = 1.000000E+01 DT = 1.000000E+01

Premature termination. isweep = 10 iz = 1 istep = 2 ithyd = 1 variable being solved is P1 subroutine is SOLVER

************************************************** ********** TIME STP= 2 SWEEP NO= 11 ZSLAB NO= 1 ITERN NO= 1 TIME = 2.000000E+01 DT = 1.000000E+01

************************************************** ********** SATLIT RUN NUMBER = 1 ; LIBRARY REF.= 771 RUN COMPLETED AT 11:11:28 ON THURSDAY, 29 JULY 2004 MACHINE-CLOCK TIME OF RUN = 0 SECONDS. TIME/(VARIABLES*CELLS*TSTEPS*SWEEPS*ITS) = 0.000E+00 ************************************************** **********
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Old   July 29, 2004, 18:55
Default Re: Please help: Library case W771: No convergence
  #4
leon mills
Guest
 
Posts: n/a
Alex,

Look at the relaxation factor on pressure, at a first glance it looks to me like it is 'too tight' (1e-6). I would suggest that a number like 0.1 or 0.01 might be a good start to see if this is the problem, then move towards 1e-6 if required.

This maybe set for a specfic reason, but this is what I normally do when I encounter a similar problem.

Hope this helps,

Leon
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Old   August 3, 2004, 09:19
Default Re: Please help: Library case W771: No convergence
  #5
Alex Costa
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Leon, Let me tell you what I have done: I increased LINEAR RELAXATION FOR P1 TO 1.0E-1 as you suggested. That did a better result: instead of premature termination at time step 28 I got a premature termination at time step 33. Next I reduced the number of time steps from 100 to 50. Now the run does not have premature termination messages but it is still very far from convergence : ressum/resref for P1 is 1e5. Any clue about how going further are welcome.

Thanks,

Alex

P.S. If it is not asking too much: why the number of time steps is important for this run?
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Old   August 3, 2004, 18:54
Default Re: Please help: Library case W771: No convergence
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leon mills
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Alex,

As I understand it the number of iterations selected is part of the convergance. Generaly the larger the cell size (CFD grid) the more iterations it will take for the solution to converge. This part of the reason why selecting the right grid for your application is important.

Are there any other feilds that when you look at the run time graphs that a fluctuating - maybe the relaxation parameters on these need a bit more work.

For me I try pressure then velocity then the energy terms.

Try also 'relaxing' the RESFAC = 1.000000E-03 to 0.1. At least until the model is a bit more stable.

Another question - did you run the library case succesfully ?

Feel free to respond at the email address linked to my user name - it might be a faster process.

Regards,

Leon
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