Phi.H

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/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2011-2015 OpenFOAM Foundation
     \\/     M anipulation  |
-------------------------------------------------------------------------------
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.
 
    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    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
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
Class
    Foam::PhiLimiter
 
Description
    Class with limiter function which returns the limiter for the
    Phi differencing scheme.
 
    Used in conjunction with the template class PhiScheme.
 
SourceFiles
    Phi.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef Phi_H
#define Phi_H
 
#include "vector.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
/*---------------------------------------------------------------------------*\
                           Class PhiLimiter Declaration
\*---------------------------------------------------------------------------*/
 
class PhiLimiter
{
    scalar k_;
 
public:
 
    PhiLimiter(Istream& is)
    :
        k_(readScalar(is))
    {
        if (k_ < 0 || k_ > 1)
        {
            FatalIOErrorInFunction(is)
                << "coefficient = " << k_
                << " should be >= 0 and <= 1"
                << exit(FatalIOError);
        }
    }
 
    scalar limiter
    (
        const scalar cdWeight,
        const scalar faceFlux,
        const vector& PhiP,
        const vector& PhiN,
        const vector& Sf,
        const scalar&
    ) const
    {
        scalar phiP = Sf&PhiP;
        scalar phiN = Sf&PhiN;
 
        scalar phiU;
 
        if (faceFlux > 0)
        {
            phiU = phiP;
        }
        else
        {
            phiU = phiN;
        }
 
        scalar phiCD = cdWeight*phiP + (1 - cdWeight)*phiN;
 
        // Calculate the effective limiter for the Phi interpolation
        //scalar PLimiter =
        //    (1.0 - k_) + k_*(faceFlux - phiU)/stabilise(phiCD - phiU, SMALL);
 
        scalar PLimiter =
            ((faceFlux - phiU)/stabilise(phiCD - phiU, SMALL) + k_);
 
        // Limit the limiter between upwind and central
        return max(min(PLimiter, 1), 0);
    }
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //