gaussGrad.C

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    Copyright (C) 2018-2021 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.

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#include "gaussGrad.H"
#include "extrapolatedCalculatedFvPatchField.H"

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

template<class Type>
Foam::tmp
<
    Foam::GeometricField
    <
        typename Foam::outerProduct<Foam::vector, Type>::type,
        Foam::fvPatchField,
        Foam::volMesh
    >
>
Foam::fv::gaussGrad<Type>::gradf
(
    const GeometricField<Type, fvsPatchField, surfaceMesh>& ssf,
    const word& name
)
{
    typedef typename outerProduct<vector, Type>::type GradType;
    typedef GeometricField<GradType, fvPatchField, volMesh> GradFieldType;

    const fvMesh& mesh = ssf.mesh();

    tmp<GradFieldType> tgGrad
    (
        new GradFieldType
        (
            IOobject
            (
                name,
                ssf.instance(),
                mesh,
                IOobject::NO_READ,
                IOobject::NO_WRITE
            ),
            mesh,
            dimensioned<GradType>(ssf.dimensions()/dimLength, Zero),
            fvPatchFieldBase::extrapolatedCalculatedType()
        )
    );
    GradFieldType& gGrad = tgGrad.ref();

    const labelUList& owner = mesh.owner();
    const labelUList& neighbour = mesh.neighbour();
    const vectorField& Sf = mesh.Sf();

    Field<GradType>& igGrad = gGrad;
    const Field<Type>& issf = ssf;

    forAll(owner, facei)
    {
        const GradType Sfssf = Sf[facei]*issf[facei];

        igGrad[owner[facei]] += Sfssf;
        igGrad[neighbour[facei]] -= Sfssf;
    }

    forAll(mesh.boundary(), patchi)
    {
        const labelUList& pFaceCells =
            mesh.boundary()[patchi].faceCells();

        const vectorField& pSf = mesh.Sf().boundaryField()[patchi];

        const fvsPatchField<Type>& pssf = ssf.boundaryField()[patchi];

        forAll(mesh.boundary()[patchi], facei)
        {
            igGrad[pFaceCells[facei]] += pSf[facei]*pssf[facei];
        }
    }

    igGrad /= mesh.V();

    gGrad.correctBoundaryConditions();

    return tgGrad;
}


template<class Type>
Foam::tmp
<
    Foam::GeometricField
    <
        typename Foam::outerProduct<Foam::vector, Type>::type,
        Foam::fvPatchField,
        Foam::volMesh
    >
>
Foam::fv::gaussGrad<Type>::calcGrad
(
    const GeometricField<Type, fvPatchField, volMesh>& vsf,
    const word& name
) const
{
    typedef typename outerProduct<vector, Type>::type GradType;
    typedef GeometricField<GradType, fvPatchField, volMesh> GradFieldType;

    tmp<GradFieldType> tgGrad
    (
        gradf(tinterpScheme_().interpolate(vsf), name)
    );
    GradFieldType& gGrad = tgGrad.ref();

    correctBoundaryConditions(vsf, gGrad);

    return tgGrad;
}


template<class Type>
void Foam::fv::gaussGrad<Type>::correctBoundaryConditions
(
    const GeometricField<Type, fvPatchField, volMesh>& vsf,
    GeometricField
    <
        typename outerProduct<vector, Type>::type, fvPatchField, volMesh
    >& gGrad
)
{
    auto& gGradbf = gGrad.boundaryFieldRef();

    forAll(vsf.boundaryField(), patchi)
    {
        if (!vsf.boundaryField()[patchi].coupled())
        {
            const vectorField n
            (
                vsf.mesh().Sf().boundaryField()[patchi]
              / vsf.mesh().magSf().boundaryField()[patchi]
            );

            gGradbf[patchi] += n *
            (
                vsf.boundaryField()[patchi].snGrad()
              - (n & gGradbf[patchi])
            );
        }
     }
}


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