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Old   March 6, 2009, 04:05
Default Hi Vishal, can you give me
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Tian
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Hi Vishal,

can you give me a hint where did you find in the OpenFOAM code T.relax()? Thanks

Bye
Thomas
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Old   March 6, 2009, 08:28
Default Hello Thomas it seems that
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Leonardo Honfi Camilo
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Hello Thomas

it seems that I got here a little late, the link that you have posted has reached its limit, could you perhaps mail me the file?

thanks

leo
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Old   March 6, 2009, 08:40
Default Hi, try this one: http:/
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Hi,

try this one:

http://rapidshare.com/files/20600643...eFoam.tar.html

Bye
Thomas
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Old   March 6, 2009, 08:47
Default thanks
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thanks
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Old   March 6, 2009, 12:40
Default Hi Tian, I found such a rel
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Vishal Nandigana
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Hi Tian,

I found such a relaxation technique mentioned by Prof Hrv.. in this forum

I would like to know precisely what each one exactly does in openFOAM... and which is more advantageous...

http://www.cfd-online.com/cgi-bin/Op...ow.cgi?1/10111

Regards

Vishal
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Old   July 30, 2009, 06:28
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Hi, dear Foamers, I also meet the same problem when use simpleFoam to do a simple case. I have try some suggestions in this thread, but fails. any other comments?

Thank you very much. have a nice day.
Chiven


Time = 8
DILUPBiCG: Solving for Ux, Initial residual = 0.0154965, Final residual = 3.56285e-05, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.00436824, Final residual = 3.31732e-05, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.00323331, Final residual = 3.00037e-05, No Iterations 1
GAMG: Solving for p, Initial residual = 0.961782, Final residual = 0.00929941, No Iterations 3
time step continuity errors : sum local = 1.72947e+25, global = 2.12055e+19, cumulative = 2.12055e+19
DILUPBiCG: Solving for epsilon, Initial residual = 0.999551, Final residual = 0.0140238, No Iterations 1
bounding epsilon, min: -1.97709e+32 max: 1.13481e+50 average: 7.81416e+44
DILUPBiCG: Solving for k, Initial residual = 0.999999, Final residual = 0.0180508, No Iterations 1
bounding k, min: -1.56134e+22 max: 6.46051e+40 average: 1.40592e+36
ExecutionTime = 72.457 s ClockTime = 73 s
Time = 9
DILUPBiCG: Solving for Ux, Initial residual = 0.258312, Final residual = 0.00394438, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.322752, Final residual = 0.00548298, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.134508, Final residual = 0.00229101, No Iterations 1
GAMG: Solving for p, Initial residual = 0.999988, Final residual = 0.00957924, No Iterations 10
time step continuity errors : sum local = 6.46819e+24, global = 6.00802e+18, cumulative = 2.72135e+19
DILUPBiCG: Solving for epsilon, Initial residual = 0.0935502, Final residual = 1.68919e-17, No Iterations 1
bounding epsilon, min: -5.66454e+59 max: 1.62366e+65 average: 4.84566e+60
DILUPBiCG: Solving for k, Initial residual = 0.271442, Final residual = 0.00498093, No Iterations 1
bounding k, min: -4.51792e+38 max: 2.46246e+56 average: 5.53053e+51
ExecutionTime = 83.2949 s ClockTime = 84 s
Time = 10
DILUPBiCG: Solving for Ux, Initial residual = 0.213457, Final residual = 0.000426911, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.194438, Final residual = 0.000360278, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.140209, Final residual = 0.000161624, No Iterations 1
GAMG: Solving for p, Initial residual = 0.00575245, Final residual = 5.53957e-05, No Iterations 1
time step continuity errors : sum local = 6.46819e+49, global = 8.29418e+43, cumulative = 8.29418e+43
DILUPBiCG: Solving for epsilon, Initial residual = 2.16312e-18, Final residual = 2.16312e-18, No Iterations 0
bounding epsilon, min: 1.59155e-21 max: 2.55066e+77 average: 2.55902e+72
DILUPBiCG: Solving for k, Initial residual = 0.00017126, Final residual = 6.14596e-07, No Iterations 1
bounding k, min: -9.10313e+53 max: 3.20352e+90 average: 3.67758e+85
ExecutionTime = 90.6045 s ClockTime = 91 s
Time = 11
DILUPBiCG: Solving for Ux, Initial residual = 0.0174846, Final residual = 0.000301742, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.00157757, Final residual = 2.24617e-05, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.0368666, Final residual = 0.000505577, No Iterations 1
#0 _ZN4Foam5error10printStackERNS_7OstreamE-0xb383f0
in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/lib/linuxIA64GccDPOpt/libOpenFOAM.so"
#1 _ZN4Foam6sigFpe13sigFpeHandlerEi-0xb01820
in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/lib/linuxIA64GccDPOpt/libOpenFOAM.so"
#2 Uninterpreted: [0xa0000000000107e0]
#3 _ZN4Foam17DICPreconditioner15calcReciprocalDERNS_5 FieldIdEERKNS_9lduMatrixE-0xef5f6e
in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/lib/linuxIA64GccDPOpt/libOpenFOAM.so"
#4 _ZN4Foam11DICSmootherC1ERKNS_4wordERKNS_9lduMatrix ERKNS_10FieldFieldINS_5FieldEdEESB_RKNS_8UPtrListI KNS_17lduInterfaceFieldEEE-0xefe2d0
in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/lib/linuxIA64GccDPOpt/libOpenFOAM.so"
#5 _ZN4Foam9lduMatrix8smoother30addsymMatrixConstruct orToTableINS_11DICSmootherEE3NewERKNS_4wordERKS0_R KNS_10FieldFieldINS_5FieldEdEESE_RKNS_8UPtrListIKN S_17lduInterfaceFieldEEE-0xeb2c00
in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/lib/linuxIA64GccDPOpt/libOpenFOAM.so"
#6 _ZN4Foam9lduMatrix8smoother3NewERKNS_4wordERKS0_RK NS_10FieldFieldINS_5FieldEdEESB_RKNS_8UPtrListIKNS _17lduInterfaceFieldEEERNS_7IstreamE-0xf1a020
in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/lib/linuxIA64GccDPOpt/libOpenFOAM.so"
#7 _ZNK4Foam10GAMGSolver10initVcycleERNS_7PtrListINS_ 5FieldIdEEEES5_RNS1_INS_9lduMatrix8smootherEEE-0xedc9e0
in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/lib/linuxIA64GccDPOpt/libOpenFOAM.so"
#8 _ZNK4Foam10GAMGSolver5solveERNS_5FieldIdEERKS2_h-0xed4f70
in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/lib/linuxIA64GccDPOpt/libOpenFOAM.so"
#9 _ZN4Foam8fvMatrixIdE5solveERNS_7IstreamE-0x1f46d20
in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/lib/linuxIA64GccDPOpt/libfiniteVolume.so"
#10 main in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/applications/bin/linuxIA64GccDPOpt/simpleFoam"
#11 __libc_start_main-0x739090
in "/lib/tls/libc.so.6.1"
#12 _start in "/home/g2/e090012/OpenFOAM/OpenFOAM-1.5/applications/bin/linuxIA64GccDPOpt/simpleFoam"
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Old   August 22, 2009, 10:27
Cool
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Krzysztof Przysowa
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Hi chiven,
there is obviously something causing time step continuity errors being sky high.
I recall that I had a similar problem when, by mistake, in boundary definition velocity direction was from outlet to inlet. Of course it should be other way around.
So, I would recommend to check your boundary conditions.
Cheers
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Old   August 23, 2009, 05:13
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J. Cai
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Hello, Krzysztof, thanks a lot for your reply. You are right, and now the problems are over.

Best regards,
Chiven
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Old   November 27, 2009, 08:16
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Michael Schwarz
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Hey Guys!!

I have the same problemes changing my solvers to GAMG like mayol had.

FOAM FATAL IO ERROR : expected 'true' or 'false', found yes
file: /opt/OpenFOAM/caelinux-1.4.1/run/BLENDE/system/fvSolution:::scaleCorrection at line 41.
From function operator>>(Istream&, bool&)
in file primitives/bool/boolIO.C at line 72.
FOAM exiting

I just started working with OpenFoam and still be playing arround a bit. Here is my checkMesh log:

Create polyMesh for time = constant
Time = constant

Mesh stats
points: 27304
edges: 172646
faces: 283432
internal faces: 268924
cells: 138089
boundary patches: 3
point zones: 0
face zones: 0
cell zones: 0

Number of cells of each type:
hexahedra: 0
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 138089
polyhedra: 0

Checking topology...
Boundary definition OK.
Point usage OK.
Upper triangular ordering OK.
Topological cell zip-up check OK.
Face vertices OK.
Face-face connectivity OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface
In 122 77 ok (not multiply connected)
Out 172 102 ok (not multiply connected)
Walls 14214 7137 ok (not multiply connected)

Checking geometry...
Domain bounding box: (-0.6 0 -0.6) (0.6 5 0.6)
Boundary openness (4.08264e-17 2.77916e-17 3.03938e-17) OK.
Max cell openness = 1.48446e-16 OK.
Max aspect ratio = 4.30296 OK.
Minumum face area = 1.32319e-05. Maximum face area = 0.028895. Face area magnitudes OK.
Min volume = 2.50715e-08. Max volume = 0.00159632. Total volume = 5.60409. Cell volumes OK.
Mesh non-orthogonality Max: 51.4236 average: 15.1122
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.791886 OK.
Min/max edge length = 0.00478093 0.295993 OK.
All angles in faces OK.
All face flatness OK.

Mesh OK.

To me, it seems that the mesh-scale is fine.

Any idea what causes the problems? Thanks for Help!
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Old   November 28, 2009, 05:32
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Hi Michael,

Quote:
FOAM FATAL IO ERROR : expected 'true' or 'false', found yes
file: /opt/OpenFOAM/caelinux-1.4.1/run/BLENDE/system/fvSolution:::scaleCorrection at line 41.
Have you had a look at system/fvSolution at line 41 and does it read there "yes" for "scaleCorrection"? Put "true" there instead of "yes" and see what happens.
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Old   November 29, 2009, 13:28
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Michael Schwarz
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Hi Gijs,

sorry for the late reply. Have been away for the weekend...

I tried to Put "true" there but the same errors occure. It is the same error for U,p,k and epsilon....

No idea what to do
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Old   January 26, 2010, 07:46
Default time step continuity errors...remain
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George Pechlivanoglou
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Hello everyone!

I also get the time step continuity error and I am having a hard time solving the problem. My grid is built with gmsh and engrid (extrusion, boundary conditions, OpenFOAM export). It is unstructured, quasi 2D (i.e. sides are BL type = empty) and represents a multi element airfoil.

the grid works perfectly with simpleFoam and komegaSST until 16 AoA. When I try computations at 25 AoA I get the time step continuity errors. I have tried all the proposals from this thread (e.g. reduction of relaxation factors, high initial epsilon, smaller time step) it still crashes.

I am pretty sure that the problem has to do with the massive separation due to high AoA...but I have no idea what to do next.
Any proposals ??

Thanx a lot for you help!

cheers
George
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Old   January 28, 2010, 15:20
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Gijsbert Wierink
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Hi George,

I'm not an aerodynamicist or anything, but could it be related to the pressure correction method? SimpleFoam uses the SIMPLE algorithm (of course ), which can be quite sensitive to relaxations factors and time step. The PISO algorithm may be less sensitive and contains an extra correction for skewness (do you have a more skewed mesh for higher angle of attack?). Have you tried e.g. pisoFoam (or turbFoam) to test this or do you need to use simpleFoam? Well, don't know if this is of any help, but it just comes to mind.
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Old   January 28, 2010, 16:53
Default SimpleFoam, Time step continuity errors
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George Pechlivanoglou
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gwierink thanks for the tips

I am actually building my unstructured grids with Gmsh and then extrude them with EnGrid...meaning that the whole process is more or less standard for any airfoil I use. I therefore think that the grid itself is not really problematic. My checkMesh does not give me any errors...and the aspect ratios and expansion ratios are good. It might be the sensitivity of simpleFoam to relaxation and time step....but maybe I try to find some other possible solutions as well before I change the model.

The problem is that I am running the computations via script which goes from one AoA to the other in order to get the airfoil polar at the end. I suspect that is I change solver between AoA then my polar will have sort of..random errors.

Anyway, thanx again for the tips!!

cheers
George
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Old   February 10, 2010, 22:57
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Jonathas Assunção de Castro
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Quote:
Originally Posted by tian View Post
Hi Eduarda,

can you compile the original simpleFoam solver without trouble? If yes, you can replace four files from the simpleConvergenceFoam to the original folder (make a copy before):

initConvergenceCheck.H
convergenceCheck.H
pEqn.H
UEqn.H

Bye
Thomas
Hello Thomas,

Could you send to me the following files, please?

initConvergenceCheck.H
convergenceCheck.H
pEqn.H
UEqn.H

Tnahks
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Old   April 11, 2010, 06:29
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Hello All,

I am trying to simulate an impingingjet using the simpleFoam in OF1.6.x. I am trying to follow the threads and tried different things. But I am still getting the same error. I am posting my error and attaching my initial bc. Your support will be greatly appreciated.

Time = 759

DILUPBiCG: Solving for Ux, Initial residual = 0.364807, Final residual = 0.0331038, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.401396, Final residual = 0.0185339, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.439448, Final residual = 0.0046591, No Iterations 1
GAMG: Solving for p, Initial residual = 0.569614, Final residual = 0.00428777, No Iterations 66
time step continuity errors : sum local = 3.14096e+42, global = 3.09629e+39, cumulative = 6.80133e+40
DILUPBiCG: Solving for epsilon, Initial residual = 1.08298e-09, Final residual = 1.08298e-09, No Iterations 0
DILUPBiCG: Solving for k, Initial residual = 0.000115294, Final residual = 2.84805e-06, No Iterations 2
ExecutionTime = 47327.3 s ClockTime = 48069 s

Time = 760

DILUPBiCG: Solving for Ux, Initial residual = 0.506818, Final residual = 0.00973123, No Iterations 2
DILUPBiCG: Solving for Uy, Initial residual = 0.603294, Final residual = 0.0122224, No Iterations 2
DILUPBiCG: Solving for Uz, Initial residual = 0.280386, Final residual = 0.00518198, No Iterations 2
GAMG: Solving for p, Initial residual = 0.0695246, Final residual = 0.000686704, No Iterations 30
time step continuity errors : sum local = 1.41992e+43, global = 4.71133e+41, cumulative = 5.39147e+41
DILUPBiCG: Solving for epsilon, Initial residual = 3.87187e-11, Final residual = 3.87187e-11, No Iterations 0
DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 0.0894909, No Iterations 1
bounding k, min: -7.27376e+51 max: 5.05817e+89 average: 5.17561e+84
ExecutionTime = 47386.5 s ClockTime = 48159 s

Time = 761

DILUPBiCG: Solving for Ux, Initial residual = 0.417362, Final residual = 0.0145424, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.51114, Final residual = 0.0224704, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0.376437, Final residual = 0.0288099, No Iterations 1
GAMG: Solving for p, Initial residual = 0.629327, Final residual = 0.00528483, No Iterations 8
time step continuity errors : sum local = 1.11456e+78, global = 4.87405e+75, cumulative = 4.87405e+75
DILUPBiCG: Solving for epsilon, Initial residual = 4.23728e-09, Final residual = 4.23728e-09, No Iterations 0
#0 Foam::error:rintStack(Foam::Ostream&) in "/home/jish/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/home/jish/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libOpenFOAM.so"
#2 ?? in "/lib/libc.so.6"
#3 Foam::PBiCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/home/jish/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libOpenFOAM.so"
#4 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/home/jish/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libfiniteVolume.so"
#5 Foam::lduMatrix::solverPerformance Foam::solve<double>(Foam::tmp<Foam::fvMatrix<doubl e> > const&) in "/home/jish/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libincompressibleRASModels.so"
#6 Foam::incompressible::RASModels::kEpsilon::correct () in "/home/jish/OpenFOAM/OpenFOAM-1.6.x/lib/linux64GccDPOpt/libincompressibleRASModels.so"
#7 main in "/home/jish/OpenFOAM/OpenFOAM-1.6.x/applications/bin/linux64GccDPOpt/simpleFoam"
#8 __libc_start_main in "/lib/libc.so.6"
#9 _start at /build/buildd/eglibc-2.10.1/csu/../sysdeps/x86_64/elf/start.S:116
Floating point exception




thanks

regards
jish
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