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-   -   problems with turbFoam (small deltaT) (http://www.cfd-online.com/Forums/openfoam-solving/64830-problems-turbfoam-small-deltat.html)

 sven82 May 26, 2009 05:46

problems with turbFoam (small deltaT)

1 Attachment(s)
I try to simulate a naca0012 with turbFoam (60degree) (picture attachment)

with this parameters:

circle mesh around the naca ~500.000 cells (R~10m)
finest cell on caca ~1e-4

patches are
Naca = wall
inletOutlet = the hole circle around the naca
fronandback = cyclic

Euler;
divSchemes upwind;
RASModel LienLeschzinerLowRe;
Re 10^6

Courant Number mean: 9.73987e-07 max: 3.02009
deltaT = 7.61855e-19
DILUPBiCG: Solving for Ux, Initial residual = 5.03753e-05, Final residual = 1.87688e-06, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 0.000688879, Final residual = 4.79751e-06, No Iterations 2
DILUPBiCG: Solving for Uz, Initial residual = 0.186895, Final residual = 9.20787e-07, No Iterations 2
DICPCG: Solving for p, Initial residual = 0.995746, Final residual = 9.57816e-06, No Iterations 494
time step continuity errors : sum local = 2.12007e-13, global = -2.51268e-16, cumulative = 6.45217e-14
DICPCG: Solving for p, Initial residual = 0.949774, Final residual = 9.6231e-06, No Iterations 493
time step continuity errors : sum local = 2.40166e-13, global = -2.255e-16, cumulative = 6.42962e-14
DICPCG: Solving for p, Initial residual = 0.955354, Final residual = 9.89174e-06, No Iterations 492
time step continuity errors : sum local = 2.47449e-13, global = -1.86303e-17, cumulative = 6.42776e-14
ExecutionTime = 474.19 s ClockTime = 474 s

thats the facts,

first of all i think openFoam are a implicit solver (Co unimportant), thats obviously not the case because the simulation broken up with to high deltaT :confused:

As second step I try the option adjustTimeStep with a maxCo of 1, the conclusion is a very low timestep (|<1^ -20) and also a stop of the simulation after a few timesteps later whit this message

DILUPBiCG: Solving for Ux, Initial residual = 4.20658e-05, Final residual = 2.20822e-06, No Iterations 1
[6] #0 Foam::error::printStack(Foam::Ostream&)DILUPBiCG: Solving for Uy, Initial residual = 0.00129761, Final residual = 1.62481e-06, No Iterations 3
DILUPBiCG: Solving for Uz, Initial residual = 0.165781, Final residual = 1.73234e-06, No Iterations 2
in "/usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
[6] #1 Foam::sigFpe::sigFpeHandler(int) in "/usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libOpenFOAM.so"
[6] #2 ?? in "/lib64/libc.so.6"
[6] #3 void Foam::processorLduInterface::compressedSend<Foam:: Vector<double> >(Foam::Pstream::commsTypes, Foam::UList<Foam::Vector<double> > const&) const in "/usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libfiniteVolume.so"
[6] #4 Foam::processorFvPatchField<Foam::Vector<double> >::initEvaluate(Foam::Pstream::commsTypes) in "/usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libfiniteVolume.so"
[6] #5 Foam::GeometricField<Foam::Vector<double>, Foam::fvPatchField, Foam::volMesh>::GeometricBoundaryField::evaluate() in "/usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64GccDPOpt/turbFoam"
[6] #6 Foam::fvMatrix<Foam::Vector<double> >::H() const in "/usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64GccDPOpt/turbFoam"
[6] #7 main in "/usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64GccDPOpt/turbFoam"
[6] #8 __libc_start_main in "/lib64/libc.so.6"
[dwoblx027:08797] *** Process received signal ***
[dwoblx027:08797] Signal: Floating point exception (8)
[dwoblx027:08797] Signal code: (-6)
[dwoblx027:08797] [ 0] /lib64/libc.so.6 [0x2b53c21375b0]
[dwoblx027:08797] [ 1] /lib64/libc.so.6(gsignal+0x35) [0x2b53c2137535]
[dwoblx027:08797] [ 2] /lib64/libc.so.6 [0x2b53c21375b0]
[dwoblx027:08797] [ 3] /usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libfiniteVolume.so(_ZNK4Foam21processorLduInterfac e14compressedSendINS_6VectorIdEEEEvNS_7Pstream10co mmsTypesERKNS_5UListIT_EE+0xdf) [0x2b53c04a80cf]
[dwoblx027:08797] [ 4] /usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/lib/linux64GccDPOpt/libfiniteVolume.so(_ZN4Foam21processorFvPatchField INS_6VectorIdEEE12initEvaluateENS_7Pstream10commsT ypesE+0x6a) [0x2b53c04aacda]
[dwoblx027:08797] [ 5] /usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64GccDPOpt/turbFoam(_ZN4Foam14GeometricFieldINS_6VectorIdEENS _12fvPatchFieldENS_7volMeshEE22GeometricBoundaryFi eld8evaluateEv+0x1c6) [0x42c1f6]
[dwoblx027:08797] [ 6] /usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64GccDPOpt/turbFoam [0x44c2d8]
[dwoblx027:08797] [ 7] /usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64GccDPOpt/turbFoam [0x4156ff]
[dwoblx027:08797] [ 8] /lib64/libc.so.6(__libc_start_main+0xf4) [0x2b53c2124ae4]
[dwoblx027:08797] [ 9] /usrfem/femsys_local/OpenFOAM/OpenFOAM-1.5/applications/bin/linux64GccDPOpt/turbFoam(_ZN4Foam11regIOobject14readIfModifiedEv+0 x199) [0x414119]
[dwoblx027:08797] *** End of error message ***
[DWOBLX018][0,1,1][btl_tcp_frag.c:202:mca_btl_tcp_frag_recv] mca_btl_tcp_frag_recv: readv failed with errno=104
[DWOBLX018][0,1,3][btl_tcp_frag.c:202:mca_btl_tcp_frag_recv] mca_btl_tcp_frag_recv: readv failed with errno=104
mpirun noticed that job rank 0 with PID 15544 on node DWOBLX018 exited on signal 15 (Terminated).
6 additional processes aborted (not shown)

I got no idea what I can chance for simulation run with a not too small timestep. :confused:

best wishes
Sven

 wolle1982 May 26, 2009 08:03

try Co=1
try frontAndBack = empty (not cyclic)
try circle = inlet only

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