[zordiack]

Hi, I just made initial implementation of viscous heating into chtMultiRegionFoam. This is the modified EEqn:

    volScalarField& he = thermo.he();
    volTensorField gradU = fvc::grad(U);
    // tau = 2*mu*D, D = deformation rate tensor
    volTensorField tau = turb.muEff() * (gradU + gradU.T());

    fvScalarMatrix EEqn
    (
        fvm::ddt(rho, he) + fvm::div(phi, he)
      + fvc::ddt(rho, K) + fvc::div(phi, K)
      + (
            he.name() == "e"
          ? fvc::div
            (
                fvc::absolute(phi/fvc::interpolate(rho), U),
                p,
                "div(phiv,p)"
            )
          : -dpdt
        )
      - fvm::laplacian(turb.alphaEff(), he)
     ==
        rho*(U&g)
      + fvc::div(tau & U) // viscous heating
      + rad.Sh(thermo)
      + fvOptions(rho, he)
    );

Is this the correct way to do it? If not, how could it be improved? For sources I used http://cfd.direct/openfoam/energy-equation/ and the excellent pdf made by Tobias Holtzmann, which you can find here http://www.holzmann-cfd.de/index.php...s-and-openfoam.

I basically tried to implement the other missing mechanical source, which is div(tau & U), and tau = turb.muEff() * (gradU + gradU.T()).

I'm wishing for comments and feedback, you can get the code from here:

https://github.com/zordiack/foam-dev

[nbuchi]

Hi, Zordiack,

I have adopted your viscous heating code in chtMultiRegionSimpleFoam. In addition, I implemented a temperature-dependent viscosity model.

My investigations deal with journal bearings. So I compared the calculation results with a state-of-the-art bearing program.

Standing now, I am very satisfied.

Thank you very much
nbuchi

[AMitgM95]

Hello,

Could you please help in writing the viscous dissipation term in OpenFOAM v9? I tried but was unable to figure out how to write the expression for shear-stress symmetric tensor ((gradU + gradU.T())).