cellLimitedGrad.C

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    Copyright (C) 2018 OpenFOAM Foundation
    Copyright (C) 2021 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.
 
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
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#include "cellLimitedGrad.H"
#include "gaussGrad.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
template<class Type, class Limiter>
void Foam::fv::cellLimitedGrad<Type, Limiter>::limitGradient
(
    const Field<scalar>& limiter,
    Field<vector>& gIf
) const
{
    gIf *= limiter;
}
 
 
template<class Type, class Limiter>
void Foam::fv::cellLimitedGrad<Type, Limiter>::limitGradient
(
    const Field<vector>& limiter,
    Field<tensor>& gIf
) const
{
    forAll(gIf, celli)
    {
        gIf[celli] = tensor
        (
            cmptMultiply(limiter[celli], gIf[celli].x()),
            cmptMultiply(limiter[celli], gIf[celli].y()),
            cmptMultiply(limiter[celli], gIf[celli].z())
        );
    }
}
 
 
template<class Type, class Limiter>
void Foam::fv::cellLimitedGrad<Type, Limiter>::calcGrad
(
    GeometricField
    <
        typename outerProduct<vector, Type>::type,
        fvPatchField,
        volMesh
    >& g,
    const GeometricField<Type, fvPatchField, volMesh>& vsf
) const
{
    const fvMesh& mesh = vsf.mesh();
 
    basicGradScheme_().calcGrad(g, vsf);
 
    if (k_ < SMALL)
    {
        return;
    }
 
    const labelUList& owner = mesh.owner();
    const labelUList& neighbour = mesh.neighbour();
 
    const volVectorField& C = mesh.C();
    const surfaceVectorField& Cf = mesh.Cf();
 
    Field<Type> maxVsf(vsf.primitiveField());
    Field<Type> minVsf(vsf.primitiveField());
 
    forAll(owner, facei)
    {
        const label own = owner[facei];
        const label nei = neighbour[facei];
 
        const Type& vsfOwn = vsf[own];
        const Type& vsfNei = vsf[nei];
 
        maxVsf[own] = max(maxVsf[own], vsfNei);
        minVsf[own] = min(minVsf[own], vsfNei);
 
        maxVsf[nei] = max(maxVsf[nei], vsfOwn);
        minVsf[nei] = min(minVsf[nei], vsfOwn);
    }
 
 
    const auto& bsf = vsf.boundaryField();
 
    forAll(bsf, patchi)
    {
        const fvPatchField<Type>& psf = bsf[patchi];
        const labelUList& pOwner = mesh.boundary()[patchi].faceCells();
 
        if (psf.coupled())
        {
            const Field<Type> psfNei(psf.patchNeighbourField());
 
            forAll(pOwner, pFacei)
            {
                const label own = pOwner[pFacei];
                const Type& vsfNei = psfNei[pFacei];
 
                maxVsf[own] = max(maxVsf[own], vsfNei);
                minVsf[own] = min(minVsf[own], vsfNei);
            }
        }
        else
        {
            forAll(pOwner, pFacei)
            {
                const label own = pOwner[pFacei];
                const Type& vsfNei = psf[pFacei];
 
                maxVsf[own] = max(maxVsf[own], vsfNei);
                minVsf[own] = min(minVsf[own], vsfNei);
            }
        }
    }
 
    maxVsf -= vsf;
    minVsf -= vsf;
 
    if (k_ < 1.0)
    {
        const Field<Type> maxMinVsf((1.0/k_ - 1.0)*(maxVsf - minVsf));
        maxVsf += maxMinVsf;
        minVsf -= maxMinVsf;
    }
 
 
    // Create limiter initialized to 1
    // Note: the limiter is not permitted to be > 1
    Field<Type> limiter(vsf.primitiveField().size(), pTraits<Type>::one);
 
    forAll(owner, facei)
    {
        const label own = owner[facei];
        const label nei = neighbour[facei];
 
        // owner side
        limitFace
        (
            limiter[own],
            maxVsf[own],
            minVsf[own],
            (Cf[facei] - C[own]) & g[own]
        );
 
        // neighbour side
        limitFace
        (
            limiter[nei],
            maxVsf[nei],
            minVsf[nei],
            (Cf[facei] - C[nei]) & g[nei]
        );
    }
 
    forAll(bsf, patchi)
    {
        const labelUList& pOwner = mesh.boundary()[patchi].faceCells();
        const vectorField& pCf = Cf.boundaryField()[patchi];
 
        forAll(pOwner, pFacei)
        {
            const label own = pOwner[pFacei];
 
            limitFace
            (
                limiter[own],
                maxVsf[own],
                minVsf[own],
                ((pCf[pFacei] - C[own]) & g[own])
            );
        }
    }
 
    if (fv::debug)
    {
        auto limits = gMinMax(limiter);
        auto avg = gAverage(limiter);
 
        Info<< "gradient limiter for: " << vsf.name()
            << " min = " << limits.min()
            << " max = " << limits.max()
            << " average: " << avg << endl;
    }
 
    limitGradient(limiter, g);
    g.correctBoundaryConditions();
    gaussGrad<Type>::correctBoundaryConditions(vsf, g);
}
 
 
template<class Type, class Limiter>
Foam::tmp
<
    Foam::GeometricField
    <
        typename Foam::outerProduct<Foam::vector, Type>::type,
        Foam::fvPatchField,
        Foam::volMesh
    >
>
Foam::fv::cellLimitedGrad<Type, Limiter>::calcGrad
(
    const GeometricField<Type, fvPatchField, volMesh>& vsf,
    const word& name
) const
{
    typedef typename outerProduct<vector, Type>::type GradType;
    typedef GeometricField<GradType, fvPatchField, volMesh> GradFieldType;
 
    const fvMesh& mesh = vsf.mesh();
 
    tmp<GradFieldType> tGrad
    (
        new GradFieldType
        (
            IOobject
            (
                name,
                vsf.instance(),
                mesh,
                IOobject::NO_READ,
                IOobject::NO_WRITE
            ),
            mesh,
            vsf.dimensions()/dimLength,
            fvPatchFieldBase::extrapolatedCalculatedType()
        )
    );
    
    calcGrad(tGrad.ref(), vsf);
 
    return tGrad;
}
 
 
// ************************************************************************* //