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April 3, 2013, 05:40
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so large Co!! why?
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#1 |
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New Member
chaoqing min
Join Date: Mar 2013
Posts: 10
Rep Power: 13  |
I am new for the of. why is my Co so large? it is about 10e290. The cells are divieded in x,y,z directions
 20 20 200); the velocity is z direction, 1m/s; the block is a square of cylinder and r=0.1m, l=1m.Thanks millions. |
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April 3, 2013, 06:12
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#2 |
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Senior Member
Alexey Matveichev
Join Date: Aug 2011
Location: Nancy, France
Posts: 1,938
Rep Power: 39  |
Can you post case files? Or at least checkMesh output.
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April 3, 2013, 06:33
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#3 |
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New Member
chaoqing min
Join Date: Mar 2013
Posts: 10
Rep Power: 13 |
thank you at first.
the output as follows: Create time Create mesh for time = 0 Reading transportProperties Reading field p Reading field U Reading/calculating face flux field phi Starting time loop Time = 0.0005 Courant Number mean: 4.9449e+289 max: 9.70882e+289 #0 Foam::error:  rintStack(Foam::Ostream&) in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"#1 Foam::sigFpe::sigHandler(int) in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #2 in "/lib64/libc.so.6" #3 void Foam::fvc::surfaceIntegrate<Foam::Vector<double> >(Foam::Field<Foam::Vector<double> >&, Foam::GeometricField<Foam::Vector<double>, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libfiniteVolume.so" #4 Foam::tmp<Foam::GeometricField<Foam::Vector<double >, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::surfaceIntegrate<Foam::Vector<double> >(Foam::GeometricField<Foam::Vector<double>, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libfiniteVolume.so" #5 Foam::tmp<Foam::GeometricField<Foam::Vector<double >, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::div<Foam::Vector<double> >(Foam::GeometricField<Foam::Vector<double>, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libfiniteVolume.so" #6 Foam::tmp<Foam::GeometricField<Foam::Vector<double >, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::div<Foam::Vector<double> >(Foam::tmp<Foam::GeometricField<Foam::Vector<doub le>, Foam::fvsPatchField, Foam::surfaceMesh> > const&) in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libfiniteVolume.so" #7 Foam::fv::gaussLaplacianScheme<Foam::Vector<double >, double>::fvmLaplacian(Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::GeometricField<Foam::Vector<double>, Foam::fvPatchField, Foam::volMesh> const&) in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/lib/libfiniteVolume.so" #8 in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/bin/icoFoam" #9 in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/bin/icoFoam" #10 in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/bin/icoFoam" #11 in "/home/ifas/OpenFOAM/OpenFOAM-2.1.1/platforms/linux64GccDPOpt/bin/icoFoam" #12 __libc_start_main in "/lib64/libc.so.6" #13 at /home/abuild/rpmbuild/BUILD/glibc-2.15/csu/../sysdeps/x86_64/elf/start.S:116 Gleitkomma-Ausnahme |
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April 3, 2013, 06:38
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#4 | |
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Senior Member
Alexey Matveichev
Join Date: Aug 2011
Location: Nancy, France
Posts: 1,938
Rep Power: 39 |
Maybe I was not clear enough but can you post case files? (0, constant, system folders). Also you can fun checkMesh utility and post output here.
Though it seems to be empty boundary condition somewhere. Quote:
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April 3, 2013, 06:41
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#5 |
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Senior Member
Join Date: Aug 2010
Location: Groningen, The Netherlands
Posts: 216
Rep Power: 19 |
Be careful spoiler is following:
the courant number is defined as follows: Co = (u * deltaT) / deltaX with u being the velocity delta T the time step and delta X the cell size Assuming you have a not moving/deforming mesh deltaX is constant Assuming further you turned off adjustableTimeStep, deltaT is constant as well Now using some mathematics: To blow up your courant number your speed has to go up And this is usually due to bad boundary conditions, bad meshing wrong physical setting, you may choose I hope I could contribute regards |
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| 03 april, 2013 |
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