[cookcaptain]

Anyone has the reference paper for the following code "nutkRoughWallFunctionFvPatchScalarField.C" for the computation of turbulent viscosity at rough walls? Thanks.

scalar nutkRoughWallFunctionFvPatchScalarField::fnRough
(
    const scalar KsPlus,
    const scalar Cs
) const
{
    // Return fn based on non-dimensional roughness height

    if (KsPlus < 90.0)
    {
        return pow
        (
            (KsPlus - 2.25)/87.75 + Cs*KsPlus,
            sin(0.4258*(log(KsPlus) - 0.811))
        );
    }
    else
    {
        return (1.0 + Cs*KsPlus);
    }
}


tmp<scalarField> nutkRoughWallFunctionFvPatchScalarField::calcNut() const
{
    const label patchi = patch().index();

    const turbulenceModel& turbModel = db().lookupObject<turbulenceModel>
    (
        IOobject::groupName
        (
            turbulenceModel::propertiesName,
            internalField().group()
        )
    );
    const scalarField& y = turbModel.y()[patchi];
    const tmp<volScalarField> tk = turbModel.k();
    const volScalarField& k = tk();
    const tmp<scalarField> tnuw = turbModel.nu(patchi);
    const scalarField& nuw = tnuw();

    const scalar Cmu25 = pow025(Cmu_);

    tmp<scalarField> tnutw(new scalarField(*this));
    scalarField& nutw = tnutw.ref();

    forAll(nutw, facei)
    {
        label faceCelli = patch().faceCells()[facei];

        scalar uStar = Cmu25*sqrt(k[faceCelli]);
        scalar yPlus = uStar*y[facei]/nuw[facei];
        scalar KsPlus = uStar*Ks_[facei]/nuw[facei];

        scalar Edash = E_;
        if (KsPlus > 2.25)
        {
            Edash /= fnRough(KsPlus, Cs_[facei]);
        }

        scalar limitingNutw = max(nutw[facei], nuw[facei]);

        // To avoid oscillations limit the change in the wall viscosity
        // which is particularly important if it temporarily becomes zero
        nutw[facei] =
            max
            (
                min
                (
                    nuw[facei]
                   *(yPlus*kappa_/log(max(Edash*yPlus, 1+1e-4)) - 1),
                    2*limitingNutw
                ), 0.5*limitingNutw
            );

        if (debug)
        {
            Info<< "yPlus = " << yPlus
                << ", KsPlus = " << KsPlus
                << ", Edash = " << Edash
                << ", nutw = " << nutw[facei]
                << endl;
        }
    }

    return tnutw;
}

[Shadow21]

Hello Cai,

Just wondering if you found the answer to your question? Did you find any reference?