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Old   May 31, 2010, 10:52
Default Boundary condition
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Daniele
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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
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Old   May 31, 2010, 12:54
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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.
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Old   May 31, 2010, 13:10
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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:rintStack(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:perator/<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????
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Old   June 1, 2010, 07:41
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Francois Gallard
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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...
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Old   June 9, 2010, 14:32
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Daniele
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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
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Old   June 10, 2010, 11:54
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Daniele
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What is there of wrong in my boundary condition for atmospheric boundary layer? Help me thanks!
Best regards
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