iterativeGaussGrad.C

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    Copyright (C) 2021-2023 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.
 
    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
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    (at your option) any later version.
 
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    for more details.
 
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#include "iterativeGaussGrad.H"
#include "skewCorrectionVectors.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
template<class Type>
Foam::tmp
<
    Foam::GeometricField
    <
        typename Foam::outerProduct<Foam::vector, Type>::type,
        Foam::fvPatchField,
        Foam::volMesh
    >
>
Foam::fv::iterativeGaussGrad<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;
    typedef GeometricField<GradType, fvsPatchField, surfaceMesh>
        GradSurfFieldType;
    typedef GeometricField<Type, fvsPatchField, surfaceMesh> SurfFieldType;
 
    tmp<SurfFieldType> tssf = linearInterpolate(vsf);
    const SurfFieldType& ssf = tssf.cref();
 
    tmp<GradFieldType> tgGrad = fv::gaussGrad<Type>::gradf(ssf, name);
    GradFieldType& gGrad = tgGrad.ref();
 
    const skewCorrectionVectors& skv = skewCorrectionVectors::New(vsf.mesh());
 
    scalar relax = 1;
    const bool useRelax =
        vsf.mesh().relaxField("grad(" + vsf.name() + ")", relax);
 
    for (label i = 0; i < nIter_; ++i)
    {
        tmp<GradSurfFieldType> tsgGrad = linearInterpolate(gGrad);
 
        tmp<SurfFieldType> tcorr = skv() & tsgGrad;
 
        tcorr.ref().dimensions().reset(vsf.dimensions());
 
        if (useRelax)
        {
            // relax*prediction + (1-relax)*old
            gGrad *= (1.0 - relax);
            gGrad += relax*fv::gaussGrad<Type>::gradf(tcorr + ssf, name);
        }
        else
        {
            gGrad = fv::gaussGrad<Type>::gradf(tcorr + ssf, name);
        }
    }
 
    fv::gaussGrad<Type>::correctBoundaryConditions(vsf, gGrad);
 
    return tgGrad;
}
 
 
// ************************************************************************* //