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B.C.:externalWallHeatFluxTemperature - different treatment for in and out heatflux

Hello Foamers,

I took a look at the source code of B.C.externalWallHeatFluxTemperature

and I find that there is a different treatment for inflow heat flux and outflow heat flux.

Does anybody know the theory behind this?

Thanks.

The code is copied here:

Code:



    if (oldMode_ == fixedHeatFlux)

    {

        q = q_;

    }

    else if (oldMode_ == fixedHeatTransferCoeff)

    {

        q = (Ta_ - *this)*h_;

    }

    else

    {

        FatalErrorIn

        (

            "externalWallHeatFluxTemperatureFvPatchScalarField"

            "::updateCoeffs()"

        )   << "Illegal mode " << operationModeNames[oldMode_]

            << exit(FatalError);

    }





    forAll (*this, i)

    {

        if (q[i] > 0) //in

        {

            this->refGrad()[i] = q[i]/KWall[i];

            this->refValue()[i] = 0.0;

            this->valueFraction()[i] = 0.0;

        }

        else //out

        {

            this->refGrad()[i] = 0.0;

            this->refValue()[i] = q[i]/KDelta[i] + patchInternalField()()[i];

            this->valueFraction()[i] = 1.0;

        }

    }

It seems when heat flux is in a fixedGradient b.c. is applied, whereas when heat flux is out, a fixedValue b.c. is applied.

I am totally confused for what reasons OF employs such a strategy.

nobody is interested? I am eager to know.