CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   OpenFOAM (http://www.cfd-online.com/Forums/openfoam/)
-   -   k epsilon boundary conditions for pisofoam ras solver (http://www.cfd-online.com/Forums/openfoam/71184-k-epsilon-boundary-conditions-pisofoam-ras-solver.html)

chamoun December 18, 2009 05:11

k epsilon boundary conditions for pisofoam ras solver
 
Hi,

I am struggling with understanding the proper boundary conditions for inlet, outlet and fixed walls for the epsilon, k, nut, nutilda and R files located in the 0 folder. Any feedback would be appreciated. I'm not sure when to use epsilonWallFunction, kqRWallFunction, and nutWallFunction. This is the error message that I'm getting:







----------------------------------------

Invalid wall function specification
Patch type for patch inlet must be wall
Current patch type is patch

#0 Foam::error::printStack(Foam::Ostream&) in "/home/george/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libOpenFOAM.so"
#1 Foam::error::abort() in "/home/george/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libOpenFOAM.so"
#2 Foam::fvPatchField<double>::adddictionaryConstruct orToTable<Foam::incompressible::RASModels::kqRWall FunctionFvPatchField<double> >::New(Foam::fvPatch const&, Foam::DimensionedField<double, Foam::volMesh> const&, Foam::dictionary const&) in "/home/george/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libincompressibleRASModels.so"
#3 Foam::fvPatchField<double>::New(Foam::fvPatch const&, Foam::DimensionedField<double, Foam::volMesh> const&, Foam::dictionary const&) in "/home/george/OpenFOAM/OpenFOAM-1.6/applications/bin/linux64GccDPOpt/pisoFoam"
#4 Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>::GeometricBoundaryField::GeometricB oundaryField(Foam::fvBoundaryMesh const&, Foam::DimensionedField<double, Foam::volMesh> const&, Foam::dictionary const&) in "/home/george/OpenFOAM/OpenFOAM-1.6/applications/bin/linux64GccDPOpt/pisoFoam"
#5 Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>::readField(Foam::Istream&) in "/home/george/OpenFOAM/OpenFOAM-1.6/applications/bin/linux64GccDPOpt/pisoFoam"
#6 Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>::GeometricField(Foam::IOobject const&, Foam::fvMesh const&) in "/home/george/OpenFOAM/OpenFOAM-1.6/applications/bin/linux64GccDPOpt/pisoFoam"
#7 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::incompressible::autoCreateWallFunctionField< double, Foam::incompressible::RASModels::kqRWallFunctionFv PatchField<double> >(Foam::word const&, Foam::fvMesh const&) in "/home/george/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libincompressibleRASModels.so"
#8 Foam::incompressible::autoCreateK(Foam::word const&, Foam::fvMesh const&) in "/home/george/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libincompressibleRASModels.so"
#9 Foam::incompressible::RASModels::kEpsilon::kEpsilo n(Foam::GeometricField<Foam::Vector<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::transportModel&) in "/home/george/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libincompressibleRASModels.so"
#10 Foam::incompressible::RASModel::adddictionaryConst ructorToTable<Foam::incompressible::RASModels::kEp silon>::New(Foam::GeometricField<Foam::Vector<doub le>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::transportModel&) in "/home/george/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libincompressibleRASModels.so"
#11 Foam::incompressible::RASModel::New(Foam::Geometri cField<Foam::Vector<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::transportModel&) in "/home/george/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libincompressibleRASModels.so"
#12 Foam::incompressible::turbulenceModel::addturbulen ceModelConstructorToTable<Foam::incompressible::RA SModel>::NewturbulenceModel(Foam::GeometricField<F oam::Vector<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::transportModel&) in "/home/george/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libincompressibleRASModels.so"
#13 Foam::incompressible::turbulenceModel::New(Foam::G eometricField<Foam::Vector<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::transportModel&) in "/home/george/OpenFOAM/OpenFOAM-1.6/lib/linux64GccDPOpt/libincompressibleTurbulenceModel.so"
#14 main in "/home/george/OpenFOAM/OpenFOAM-1.6/applications/bin/linux64GccDPOpt/pisoFoam"
#15 __libc_start_main in "/lib64/libc.so.6"
#16 _start at /usr/src/packages/BUILD/glibc-2.9/csu/../sysdeps/x86_64/elf/start.S:116


From function kqRWallFunctionFvPatchField::checkType()
in file derivedFvPatchFields/wallFunctions/kqRWallFunctions/kqRWallFunction/kqRWallFunctionFvPatchField.C at line 48.

FOAM aborting

Schag December 18, 2009 06:57

I'm no expert in turbulence, but I can quickly give you what I have...

each time a function is called 'variable'WallFunction, it can only be applied on a boundary which type is WALL (and no patch), what is mentionned in constant/polyMesh/boundary.

Unfortunatly, I cannot really help further.

Just my 2 cents, regards

askjak December 18, 2009 09:40

All patches with a wall function need to specified as "wall" and not "patch" (see the very first error message). But you should not supply a wallfunction on the inlet.

For example my 0/epsilon looks like this
Quote:

inlet
{
type fixedValue;
value uniform <some value that you specify>;
}
Best regards, Ask

nileshjrane April 13, 2010 14:05

Quote:

Originally Posted by chamoun (Post 240393)
Hi,

I am struggling with understanding the proper boundary conditions for inlet, outlet and fixed walls for the epsilon, k, nut, nutilda and R files located in the 0 folder. Any feedback would be appreciated. I'm not sure when to use epsilonWallFunction, kqRWallFunction, and nutWallFunction. This is the error message that I'm getting:



The value of k, eps and nu goes to zero at wall. and the inlet valu depends upon the kind of case one is solving. Basically its specifying the incoming turbulence. There are other ways to specify the valu of k and eps as well, like turbulent intencity and length scale. I am not very much sure about the inlet values but wall conditions should be zero.

chichovet May 10, 2011 05:30

R Boundary Condition
 
I have already specified k and epsilon conditions by solving the respectives equations. But I'm struggling with the R condition what value should I put for an turbulent developed flow inlet??
Thanks in advance


All times are GMT -4. The time now is 19:02.