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-   -   Boundary conditions (http://www.cfd-online.com/Forums/openfoam-pre-processing/62008-boundary-conditions.html)

seb62 October 29, 2008 06:16

Hi all, I'm starting using
 
Hi all,

I'm starting using openFoam for some tests on
the flow around a cylinder at Re=150.

I would have a few questions about the boundary conditions :

What does the inletOutlet boundary conditions represent? I saw that it switches from fixed value to zero gradient depending on the flow direction, but I cannot see the meaning of that on physical grounds. Also, it requires to specifie 2 fields (inlet and value) and I cannot find what they represent.

Also, what does the extrapolated outlet do?

Thanks very much for your answers,

Seb

vijayakumar January 15, 2009 05:11

i need to run a combustion pro
 
i need to run a combustion problem.... i used XI-foam as solver, while running some errors are coming... i need to know which solver is good for combustion problem.. and few guidelines for solving combustion problem.

mwild January 15, 2009 05:33

VIJAYAKUMAR R, please don't cr
 
VIJAYAKUMAR R, please don't cross-post your problem in every active thread. Thread-hijacking is considered very bad manners (it's like intruding into a conversation and immediately change the topic!).

Please, if you have a problem, find an appropriate thread to post it to. If you think your problem is new you can start a new discussion. In any case, make sure to exactly describe the setting: What is it you are trying to do ("solve combustion problem" is not enough!), which solvers are you using, how did you set up the simulation case, what version of OpenFOAM are you using, etc. If you get error messages, it is not enough to whine about it without telling us what they ACTUALLY say! No one here is omniscient...

When you write a request for help, put in at least as much effort as you expect from the guys who want to help you. Make it very clear that you actually tried to solve the problem on your own (including asking Google and the search functionality of this forum). Then, describe what you already tried. No one here is being paid to help you, keep that in mind. If you want that kind of support, I'm sure Henry or Hrv are more than willing to make you an offer.

Before you continue polluting this forum with your spam, please read http://openfoamwiki.net/index.php/Ho..._Message_Board

vijayakumar January 16, 2009 05:40

hi michael sir i am new user
 
hi michael sir
i am new user, i dont know sir, u people has to guide me in the right path, read your sentences once, is that right way of guiding, i am sorry for my mistake , i need to run a combustion problem.... i used XI-foam as solver of openfoam1.4 version, i created verticies, block mesh is executed, while running some errors are showing, i want to know is that a correct solver or not, and brief description to give initial boundary conditions, and how to define field values.
below i sown my blockmesh dict

vertices
(
(0 0 0)
(0 0.5 0)
(14 0 0)
(14 0.5 0)
(180 0 0)
(180 0.5 0)
(0 22.5 0)
(180 22.5 0)
(0 0 1)
(0 0.5 1)
(14 0 1)
(14 0.5 1)
(180 0 1)
(180 0.5 1)
(0 22.5 1)
(180 22.5 1)
);

blocks
(
hex (0 2 3 1 8 10 11 9) (14 1 1) simpleGrading (1 1 1)
hex (2 4 5 3 10 12 13 11) (166 1 1) simpleGrading (1 1 1)
hex (1 5 7 6 9 13 15 14) (180 22 1) simpleGrading (1 1 1)
);

edges
(
);

patches
(
patch inlet1
(
(1 9 14 6)
)
patch inlet2
(
(0 8 9 1)
)
patch outlet
(
(5 13 15 7)
)
wall topwall
(
(6 14 15 7)
(1 9 11 3)
)
wall bottomwall
(
(0 8 10 2)
(2 10 12 4)
)
empty frontandback
(
(8 9 11 10)
(0 1 3 2)
(9 14 15 13)
(1 6 7 5)
(10 11 13 12)
(2 3 5 4)
)
);

mergePatchPairs
(
);


the error mess is
Foam::error::printStack(Foam:http://www.cfd-online.com/OpenFOAM_D...part/proud.gifstream&) in "/home/openfoam14/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/home/openfoam14/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libOpenFOAM.so"
#2 ?? in "/lib64/libc.so.6"
#3 Foam::compressible::turbulenceModels::kEpsilon::kE psilon(Foam::GeometricField<do uble,> const&, Foam::GeometricField<foam::vector<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double,> const&, Foam::basicThermo&) in "/home/openfoam14/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libcompressibleTur bulenceModels.so"
#4 Foam::compressible::turbulenceModel::adddictionary ConstructorToTable<foam::compr essible::turbulencemodels::kepsilon>::New(Foam::Ge ometricField<double,> const&, Foam::GeometricField<foam::vector<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double,> const&, Foam::basicThermo&) in "/home/openfoam14/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libcompressibleTur bulenceModels.so"
#5 Foam::compressible::turbulenceModel::New(Foam::Geo metricField<double,> const&, Foam::GeometricField<foam::vector<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double,> const&, Foam::basicThermo&) in "/home/openfoam14/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libcompressibleTur bulenceModels.so"
#6 main in "/home/openfoam14/OpenFOAM/OpenFOAM-1.4.1/applications/bin/linux64GccDPOpt/XiFoa m"
#7 __libc_start_main in "/lib64/libc.so.6"
#8 Foam::regIOobject::readIfModified() in "/home/openfoam14/OpenFOAM/OpenFOAM-1.4.1/applications/bin/linux64GccDPOpt/XiFoa m"


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