velocityDampingConstraint.C

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/*---------------------------------------------------------------------------*\
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  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
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    Copyright (C) 2015 OpenFOAM Foundation
    Copyright (C) 2015-2022 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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    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
    You should have received a copy of the GNU General Public License
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\*---------------------------------------------------------------------------*/
 
#include "velocityDampingConstraint.H"
#include "addToRunTimeSelectionTable.H"
#include "fvMatrix.H"
#include "volFields.H"
 
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
namespace Foam
{
namespace fv
{
    defineTypeNameAndDebug(velocityDampingConstraint, 0);
    addToRunTimeSelectionTable
    (
        option,
        velocityDampingConstraint,
        dictionary
    );
}
}
 
 
// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
void Foam::fv::velocityDampingConstraint::addDamping(fvMatrix<vector>& eqn)
{
    // Note: we want to add
    //      deltaU/deltaT
    // where deltaT is a local time scale:
    //      U/(cbrt of volume)
    // Since directly manipulating the diagonal we multiply by volume.
 
    const scalarField& vol = mesh_.V();
    const volVectorField& U = eqn.psi();
    scalarField& diag = eqn.diag();
 
    // Count nTotCells ourselves
    // (maybe only applying on a subset)
    label nDamped(0);
    const label nTotCells(returnReduce(cells_.size(), sumOp<label>()));
 
    for (label celli : cells_)
    {
        const scalar magU = mag(U[celli]);
        if (magU > UMax_)
        {
            const scalar scale = sqr(Foam::cbrt(vol[celli]));
 
            diag[celli] += scale*(magU-UMax_);
 
            ++nDamped;
        }
    }
 
    reduce(nDamped, sumOp<label>());
 
    // Percent, max 2 decimal places
    const auto percent = [](scalar num, label denom) -> scalar
    {
        return (denom ? 1e-2*round(1e4*num/denom) : 0);
    };
 
    Info<< type() << ' ' << name_ << " damped "
        << nDamped << " ("
        << percent(nDamped, nTotCells)
        << "%) of cells, with max limit " << UMax_ << endl;
}
 
 
// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
Foam::fv::velocityDampingConstraint::velocityDampingConstraint
(
    const word& name,
    const word& modelType,
    const dictionary& dict,
    const fvMesh& mesh
)
:
    fv::cellSetOption(name, modelType, dict, mesh)
{
    read(dict);
}
 
 
// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
void Foam::fv::velocityDampingConstraint::constrain
(
    fvMatrix<vector>& eqn,
    const label fieldi
)
{
    addDamping(eqn);
}
 
 
void Foam::fv::velocityDampingConstraint::writeData(Ostream& os) const
{
    dict_.writeEntry(name_, os);
}
 
 
bool Foam::fv::velocityDampingConstraint::read(const dictionary& dict)
{
    if (fv::cellSetOption::read(dict))
    {
        coeffs_.readEntry("UMax", UMax_);
 
        if (!coeffs_.readIfPresent("UNames", fieldNames_))
        {
            fieldNames_.resize(1);
            fieldNames_.first() = coeffs_.getOrDefault<word>("U", "U");
        }
 
        fv::option::resetApplied();
 
        return true;
    }
 
    return false;
}
 
 
// ************************************************************************* //