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facing high courant number while running the case in OpenFOAM

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Old   July 10, 2012, 06:43
Default facing high courant number while running the case in OpenFOAM
  #1
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Nikhil
Join Date: Jul 2012
Location: Dalhousie,H.P.
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Hi,
I am trying to simulate the incompressible flow of water through a cylinder.The cylinder at its base have many small circular openings.I have made the mesh of required geometry through gmesh.But while executing the file in OpenFoam the courant number is becoming high.My pressure and velocity fields are as follows:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.x |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0;
boundaryField
{ bottom
{
type fixedValue;
value uniform 1.4715;
}
top
{
type fixedValue;
value uniform 0;
}
wall1
{
type zeroGradient;
}
wall2
{
type zeroGradient;
}
wall3
{
type zeroGradient;
}
wall4
{
type zeroGradient;
}
}
// ************************************************** *********************** //
U FILE:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.1.x |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 -1 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
bottom
{
type fixedValue;
value uniform (0 0 -.000004);
}
top
{
type fixedValue;
value uniform (0 0 0);
}
wall1
{
type zeroGradient;
}
wall2
{
type zeroGradient;
}
wall3
{
type zeroGradient;
}
wall4
{
type zeroGradient;
}
}
// ************************************************** *********************** //
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Old   July 30, 2012, 04:23
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Anne Lincke
Join Date: Aug 2010
Location: Hamburg
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Hey,

you can control your Courant number automatically via a proper time step.
You just have to insert certain H-Files in your solver and add two parameters in your controlDict.
See this thread

Problems with adjustable timestep control and maxCo Number

Kind Regards
Anne
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