limitVelocity.C

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/*---------------------------------------------------------------------------*\
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  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
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    Copyright (C) 2021-2025 OpenCFD Ltd.
-------------------------------------------------------------------------------
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
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
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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,
    const word& defaultAreaName
)
:
    fa::faceSetOption(name, modelType, dict, mesh, defaultAreaName),
    UName_(coeffs_.getOrDefault<word>("U", "U")),
    max_(coeffs_.get<scalar>("max"))
{
    fieldNames_.resize(1, UName_);
    applied_.resize(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();
    }
}
 
 
// ************************************************************************* //