edgeLimitedFaGrads.C

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    Copyright (C) 2016-2017 Wikki Ltd
    Copyright (C) 2023 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.
 
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#include "edgeLimitedFaGrad.H"
#include "gaussFaGrad.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
makeFaGradScheme(edgeLimitedGrad)
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace fa
{
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
template<class Type>
inline void edgeLimitedGrad<Type>::limitEdge
(
    scalar& limiter,
    const scalar maxDelta,
    const scalar minDelta,
    const scalar extrapolate
) const
{
    if (extrapolate > maxDelta + VSMALL)
    {
        limiter = min(limiter, maxDelta/extrapolate);
    }
    else if (extrapolate < minDelta - VSMALL)
    {
        limiter = min(limiter, minDelta/extrapolate);
    }
}
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
template<>
tmp<areaVectorField> edgeLimitedGrad<scalar>::calcGrad
(
    const areaScalarField& vsf,
    const word& name
) const
{
    const faMesh& mesh = vsf.mesh();
 
    tmp<areaVectorField> tGrad = basicGradScheme_().calcGrad(vsf, name);
 
    if (k_ < SMALL)
    {
        return tGrad;
    }
 
    areaVectorField& g = tGrad.ref();
 
    const labelUList& owner = mesh.owner();
    const labelUList& neighbour = mesh.neighbour();
 
    const areaVectorField& C = mesh.areaCentres();
    const edgeVectorField& Cf = mesh.edgeCentres();
 
    // Create limiter field
    scalarField limiter(vsf.internalField().size(), 1.0);
 
    const scalar rk = (1.0/k_ - 1.0);
 
    forAll(owner, edgei)
    {
        const label own = owner[edgei];
        const label nei = neighbour[edgei];
 
        const scalar vsfOwn = vsf[own];
        const scalar vsfNei = vsf[nei];
 
        scalar maxEdge = max(vsfOwn, vsfNei);
        scalar minEdge = min(vsfOwn, vsfNei);
        const scalar maxMinEdge = rk*(maxEdge - minEdge);
        maxEdge += maxMinEdge;
        minEdge -= maxMinEdge;
 
        // owner side
        limitEdge
        (
            limiter[own],
            maxEdge - vsfOwn,
            minEdge - vsfOwn,
            (Cf[edgei] - C[own]) & g[own]
        );
 
        // neighbour side
        limitEdge
        (
            limiter[nei],
            maxEdge - vsfNei,
            minEdge - vsfNei,
            (Cf[edgei] - C[nei]) & g[nei]
        );
    }
 
    // Lambda expression to update limiter for boundary edges
    auto updateLimiter = [&](const label patchi, const scalarField& fld) -> void
    {
        const labelUList& pOwner = mesh.boundary()[patchi].edgeFaces();
        const vectorField& pCf = Cf.boundaryField()[patchi];
 
        forAll(pOwner, edgei)
        {
            const label own = pOwner[edgei];
 
            const scalar vsfOwn = vsf[own];
            const scalar vsfNei = fld[edgei];
 
            scalar maxEdge = max(vsfOwn, vsfNei);
            scalar minEdge = min(vsfOwn, vsfNei);
            const scalar maxMinEdge = rk*(maxEdge - minEdge);
            maxEdge += maxMinEdge;
            minEdge -= maxMinEdge;
 
            limitEdge
            (
                limiter[own],
                maxEdge - vsfOwn,
                minEdge - vsfOwn,
                (pCf[edgei] - C[own]) & g[own]
            );
        }
    };
 
    const areaScalarField::Boundary& bsf = vsf.boundaryField();
    forAll(bsf, patchi)
    {
        const faPatchScalarField& psf = bsf[patchi];
 
        if (psf.coupled())
        {
            updateLimiter(patchi, psf.patchNeighbourField());
        }
        else if (psf.fixesValue())
        {
            updateLimiter(patchi, psf);
        }
    }
 
    if (fa::debug)
    {
        auto limits = gMinMax(limiter);
        auto avg = gAverage(limiter);
 
        Info<< "gradient limiter for: " << vsf.name()
            << " min = " << limits.min()
            << " max = " << limits.max()
            << " average: " << avg << endl;
    }
 
    g.primitiveFieldRef() *= limiter;
    g.correctBoundaryConditions();
    gaussGrad<scalar>::correctBoundaryConditions(vsf, g);
 
    return tGrad;
}
 
 
template<>
tmp<areaTensorField> edgeLimitedGrad<vector>::calcGrad
(
    const areaVectorField& vvf,
    const word& name
) const
{
    const faMesh& mesh = vvf.mesh();
 
    tmp<areaTensorField> tGrad = basicGradScheme_().grad(vvf, name);
 
    if (k_ < SMALL)
    {
        return tGrad;
    }
 
    areaTensorField& g = tGrad.ref();
 
    const labelUList& owner = mesh.owner();
    const labelUList& neighbour = mesh.neighbour();
 
    const areaVectorField& C = mesh.areaCentres();
    const edgeVectorField& Cf = mesh.edgeCentres();
 
    // Create limiter
    scalarField limiter(vvf.internalField().size(), 1.0);
 
    const scalar rk = (1.0/k_ - 1.0);
 
    forAll(owner, edgei)
    {
        const label own = owner[edgei];
        const label nei = neighbour[edgei];
 
        // owner side
        vector gradf((Cf[edgei] - C[own]) & g[own]);
 
        scalar vsfOwn = gradf & vvf[own];
        scalar vsfNei = gradf & vvf[nei];
 
        scalar maxEdge = max(vsfOwn, vsfNei);
        scalar minEdge = min(vsfOwn, vsfNei);
        const scalar maxMinEdge = rk*(maxEdge - minEdge);
        maxEdge += maxMinEdge;
        minEdge -= maxMinEdge;
 
        limitEdge
        (
            limiter[own],
            maxEdge - vsfOwn,
            minEdge - vsfOwn,
            magSqr(gradf)
        );
 
 
        // neighbour side
        gradf = (Cf[edgei] - C[nei]) & g[nei];
 
        vsfOwn = gradf & vvf[own];
        vsfNei = gradf & vvf[nei];
 
        maxEdge = max(vsfOwn, vsfNei);
        minEdge = min(vsfOwn, vsfNei);
 
        limitEdge
        (
            limiter[nei],
            maxEdge - vsfNei,
            minEdge - vsfNei,
            magSqr(gradf)
        );
    }
 
 
    // Lambda expression to update limiter for boundary edges
    auto updateLimiter = [&](const label patchi, const vectorField& fld) -> void
    {
        const labelUList& pOwner = mesh.boundary()[patchi].edgeFaces();
        const vectorField& pCf = Cf.boundaryField()[patchi];
 
        forAll(pOwner, edgei)
        {
            const label own = pOwner[edgei];
 
            const vector gradf((pCf[edgei] - C[own]) & g[own]);
 
            const scalar vsfOwn = gradf & vvf[own];
            const scalar vsfNei = gradf & fld[edgei];
 
            scalar maxEdge = max(vsfOwn, vsfNei);
            scalar minEdge = min(vsfOwn, vsfNei);
            const scalar maxMinEdge = rk*(maxEdge - minEdge);
            maxEdge += maxMinEdge;
            minEdge -= maxMinEdge;
 
            limitEdge
            (
                limiter[own],
                maxEdge - vsfOwn,
                minEdge - vsfOwn,
                magSqr(gradf)
            );
        }
    };
 
 
    const areaVectorField::Boundary& bvf = vvf.boundaryField();
    forAll(bvf, patchi)
    {
        const faPatchVectorField& psf = bvf[patchi];
 
        if (psf.coupled())
        {
            updateLimiter(patchi, psf.patchNeighbourField());
        }
        else if (psf.fixesValue())
        {
            updateLimiter(patchi, psf);
        }
    }
 
    if (fa::debug)
    {
        auto limits = gMinMax(limiter);
        auto avg = gAverage(limiter);
 
        Info<< "gradient limiter for: " << vvf.name()
            << " min = " << limits.min()
            << " max = " << limits.max()
            << " average: " << avg << endl;
    }
 
    g.primitiveFieldRef() *= limiter;
    g.correctBoundaryConditions();
    gaussGrad<vector>::correctBoundaryConditions(vvf, g);
 
    return tGrad;
}
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace fa
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// ************************************************************************* //