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variable CMU for kEpsilon model

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Old   August 1, 2017, 11:54
Default variable CMU for kEpsilon model
  #1
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Vedamt Chittlangia
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Hello,

I want to change change C_\mu for kEpsilon model and define it as a local variable for the whole domain.
So, \nu_t = C_\mu \frac{k^2}{\varepsilon} would remain same but
C_\mu = f(x,y)

Currently it is defined as dimensionedScalar. I am thinking that first I should define it as volScalarField and then do the changes.
I would appreciate any help and guidance.

Thanks
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Old   August 1, 2017, 21:03
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Sugajen
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Hi Vedamt,

I have not worked with Turbulence models but I can suggest a general way to proceed.

As you said couple of things need to be done.
1. Remove the cMu variable as a diemnsionedScalar from createFields.H and instead create a scalarField similar to P. And initialize to say zero.
Code:
Info<< "Creating field cMu\n" << endl;
volScalarField cMu
(
    IOobject
    (
        "cMu",
        runTime.timeName(),
        mesh,
        IOobject::NO_READ,   
        IOobject::NO_WRITE
    ),
    mesh,
    dimensionedScalar("cMu", dimensionSet(0,0,0,0,0,0,0), scalar(0.0))   // give proper dimensions
);
2. Now write code to give values to the cMu field both internal field and boundary.
Code:
forAll ( mesh.C(), cellI) 
{
cMu[cellI] = // your code here
}

forAll (mesh.boundaryMesh(), patchI)
{
    forAll(mesh.boundaryMesh()[patchI], faceI)
    {
         cMu.boundaryField()[patchI][faceI] = //your code here
    }
}
3. Then use it for anywhere else
4. Also do remove the value from transportProperties of case/constant/ if it is being read from that file.

best,
Sugajen
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kepsilon, turbulent viscosity, volscalarfield


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