cellModel.C

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    Copyright (C) 2017 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.

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#include "cellModel.H"
#include "pyramid.H"

// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //

Foam::vector Foam::cellModel::centre
(
    const labelList& pointLabels,
    const UList<point>& points
) const
{
    // Estimate cell centre by averaging the cell points
    vector cEst = Zero;
    for (const label pointi : pointLabels)
    {
        cEst += points[pointi];
    }
    cEst /= scalar(pointLabels.size());


    // Calculate the centre by breaking the cell into pyramids and
    // volume-weighted averaging their centres

    scalar sumV = 0;
    vector sumVc = Zero;

    forAll(faces_, facei)
    {
        const Foam::face f(pointLabels, faces_[facei]);

        const scalar pyrVol = pyramidPointFaceRef(f, cEst).mag(points);

        if (pyrVol > SMALL)
        {
            WarningInFunction
                << "zero or negative pyramid volume: " << -pyrVol
                << " for face " << facei
                << endl;
        }

        sumV -= pyrVol;
        sumVc -= pyrVol * pyramidPointFaceRef(f, cEst).centre(points);
    }

    return sumVc/(sumV + VSMALL);
}


Foam::scalar Foam::cellModel::mag
(
    const labelList& pointLabels,
    const UList<point>& points
) const
{
    // Estimate cell centre by averaging the cell points
    vector cEst = Zero;
    for (const label pointi : pointLabels)
    {
        cEst += points[pointi];
    }
    cEst /= scalar(pointLabels.size());


    // Calculate the magnitude by summing the -mags of the pyramids
    // The sign change is because the faces point outwards
    // and a pyramid is constructed from an inward pointing face
    // and the base centre-apex vector

    scalar sumV = 0;

    forAll(faces_, facei)
    {
        const Foam::face f(pointLabels, faces_[facei]);

        const scalar pyrVol = pyramidPointFaceRef(f, cEst).mag(points);

        if (pyrVol > SMALL)
        {
            WarningInFunction
                << "zero or negative pyramid volume: " << -pyrVol
                << " for face " << facei
                << endl;
        }

        sumV -= pyrVol;
    }

    return sumV;
}


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