limitVelocity.C

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    Copyright (C) 2021-2022 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.

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    under the terms of the GNU General Public License as published by
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#include "limitVelocity.H"
#include "areaFields.H"
#include "addToRunTimeSelectionTable.H"

// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //

namespace Foam
{
namespace fa
{
    defineTypeNameAndDebug(limitVelocity, 0);
    addToRunTimeSelectionTable
    (
        option,
        limitVelocity,
        dictionary
    );
}
}

// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //

Foam::fa::limitVelocity::limitVelocity
(
    const word& name,
    const word& modelType,
    const dictionary& dict,
    const fvMesh& mesh
)
:
    faceSetOption(name, modelType, dict, mesh),
    UName_(coeffs_.getOrDefault<word>("U", "U")),
    max_(coeffs_.get<scalar>("max"))
{
    fieldNames_.setSize(1, UName_);
    applied_.setSize(1, false);
}


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

bool Foam::fa::limitVelocity::read(const dictionary& dict)
{
    if (faceSetOption::read(dict))
    {
        coeffs_.readEntry("max", max_);

        return true;
    }

    return false;
}


void Foam::fa::limitVelocity::correct(areaVectorField& U)
{
    const scalar maxSqrU = sqr(max_);

    // Count nTotFaces ourselves
    // (maybe only applying on a subset)
    label nFacesAbove(0);
    const label nTotFaces(returnReduce(faces_.size(), sumOp<label>()));

    vectorField& Uif = U.primitiveFieldRef();

    for (const label facei : faces_)
    {
        auto& Uval = Uif[facei];

        const scalar magSqrUi = magSqr(Uval);

        if (magSqrUi > maxSqrU)
        {
            Uval *= sqrt(maxSqrU/max(magSqrUi, SMALL));
            ++nFacesAbove;
        }
    }

    // Handle boundaries in the case of 'all'
    label nEdgesAbove(0);

    if (!faceSetOption::useSubMesh())
    {
        for (faPatchVectorField& Up : U.boundaryFieldRef())
        {
            if (!Up.fixesValue())
            {
                for (auto& Uval : Up)
                {
                    const scalar magSqrUi = magSqr(Uval);

                    if (magSqrUi > maxSqrU)
                    {
                        Uval *= sqrt(maxSqrU/max(magSqrUi, SMALL));
                        ++nEdgesAbove;
                    }
                }
            }
        }
    }

    // Percent, max 2 decimal places
    const auto percent = [](scalar num, label denom) -> scalar
    {
        return (denom ? 1e-2*round(1e4*num/denom) : 0);
    };


    reduce(nFacesAbove, sumOp<label>());
    reduce(nEdgesAbove, sumOp<label>());

    Info<< type() << ' ' << name_ << " Limited "
        << nFacesAbove << " ("
        << percent(nFacesAbove, nTotFaces)
        << "%) of faces, with max limit " << max_ << endl;

    if (nFacesAbove || nEdgesAbove)
    {
        // We've changed internal values so give
        // boundary conditions opportunity to correct
        U.correctBoundaryConditions();
    }
}


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