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 Daniele111 May 31, 2010 10:52

Boundary condition

Hi All
If i want impose BC, in k-s model, for k, epsilon and U on inlet ma not pressure, How change 0/p file?
Thanks

 Daniele111 May 31, 2010 12:54

I simulate atmospheric boundary layer and on outlet I impose zero gradient for the pressure, but in the paper that I use like reference don't speak about pressure condition on other part of boundary.

 Daniele111 May 31, 2010 13:10

And when I run my case i have this error:

DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 1.88883e-21, No Iterations 1
DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 0.0159314, No Iterations 2
DICPCG: Solving for p, Initial residual = 1, Final residual = 0.00459912, No Iterations 15
time step continuity errors : sum local = 17748.9, global = 66.9892, cumulative = 66.9892
#0 Foam::error::printStack(Foam::Ostream&) in "/home/acconcia/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/home/acconcia/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libOpenFOAM.so"
#2 Uninterpreted:
#3 Foam::divide(Foam::Field<double>&, Foam::UList<double> const&, Foam::UList<double> const&) in "/home/acconcia/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libOpenFOAM.so"
#4 void Foam::divide<Foam::fvPatchField, Foam::volMesh>(Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&) in "/home/acconcia/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libincompressibleRASModels.so"
#5 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::operator/<Foam::fvPatchField, Foam::volMesh>(Foam::tmp<Foam::GeometricField<doub le, Foam::fvPatchField, Foam::volMesh> > const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&) in "/home/acconcia/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libincompressibleRASModels.so"
#6 Foam::incompressible::RASModels::kEpsilon::correct () in "/home/acconcia/OpenFOAM/OpenFOAM-1.6/lib/linuxGccDPOpt/libincompressibleRASModels.so"
#7
in "/home/acconcia/OpenFOAM/OpenFOAM-1.6/applications/bin/linuxGccDPOpt/simpleFoam"
#8 __libc_start_main in "/lib/tls/i686/cmov/libc.so.6"
#9
at /usr/src/packages/BUILD/glibc-2.9/csu/../sysdeps/i386/elf/start.S:122
Floating point exception

Idea????

 fgal June 1, 2010 07:41

Hi Daniele,
The solver does not accomplish the resolution of the linear systems properly. This can come from the boundary conditions, the mesh, the numerical schemes or their combination...
You could try first to use smoothSolver and GaussSeidel instead of DILU in your system/fvSolution file, which seems to be more efficient in my experience :

solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0;
nSweeps 1;

Hope it helps...

 Daniele111 June 9, 2010 14:32

Hi
Someone just simulated atmospheric boundary layer? What are correct boundary condition for p? An k epsilon? Is correct use wallShearStress to compute the stress at bottom?
Best regards

 Daniele111 June 10, 2010 11:54

1 Attachment(s)
What is there of wrong in my boundary condition for atmospheric boundary layer? Help me thanks!
Best regards

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