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Setting of Spalart–Allmaras turbulence model

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Old   March 31, 2014, 13:00
Default Setting of Spalart–Allmaras turbulence model
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Hello.

Currently I am simulating flow over a cylinder. For that purpose I am using pimpleFoam solver. I am planning to use Spalart–Allmaras turbulence model.
I am using Dirichlet boundary condition. I am having a little difficulty in setting up the turbulence model boundary condition. I have used the formula
nutilda = root(1.5) * U * I * l

Here,
U = inflow velocity = 5.07, I = Turbulence intensity = 0.1% and l = turbulent length scale = 0.02
Now my settings of NuTilda looks like this:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.2.2 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object nuTilda;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -1 0 0 0 0];

internalField uniform 0.00124;

boundaryField
{
Rotor-symmetry
{
type symmetryPlane;
}
Rotor-AMI
{
type cyclicAMI;
value uniform 0;
}
cylinder
{
type nutUSpaldingWallFunction;
value uniform 0;
}
Stator-symmetry
{
type symmetryPlane;
}
Top
{
type nutUSpaldingWallFunction;
value uniform 0;
}
Stator-AMI
{
type cyclicAMI;
value uniform 0;
}
inlet
{
type fixedValue;
value uniform 0.00124;
}
sides
{
type nutUSpaldingWallFunction;
value uniform 0;
}
outlet
{
type inletOutlet;
inletValue uniform 0.00124;
value uniform 0.00124;
}
}


// ************************************************** *********************** //
and Nu looks like this:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.2.2 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -1 0 0 0 0];

internalField uniform 0;

boundaryField
{
Rotor-symmetry
{
type symmetryPlane;
}
Rotor-AMI
{
type cyclicAMI;
value uniform 0;
}
cylinder
{
type nutUSpaldingWallFunction;
value uniform 0;
}
Stator-symmetry
{
type symmetryPlane;
}
Top
{
type nutUSpaldingWallFunction;
value uniform 0;
}
Stator-AMI
{
type cyclicAMI;
value uniform 0;
}
inlet
{
type calculated;
value uniform 0;
}
sides
{
type nutUSpaldingWallFunction;
value uniform 0;
}
outlet
{
type calculated;
value uniform 0;
}
}


// ************************************************** *********************** //

Are my methods and boundary conditions ok?

Thank you.
__________________
Happy Foaming

Last edited by Naruto; April 1, 2014 at 01:41.
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