/*---------------------------------------------------------------------------*\
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  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
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    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    Copyright (C) 2011-2016 OpenFOAM Foundation
    Copyright (C) 2019-2020 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.

    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::RASModels::RNGkEpsilon

Group
    grpRASTurbulence

Description
    Renormalization group k-epsilon turbulence model for incompressible and
    compressible flows.

    Reference:
    \verbatim
        Yakhot, V., Orszag, S. A., Thangam, S.,
        Gatski, T. B., & Speziale, C. G. (1992).
        Development of turbulence models for shear flows
        by a double expansion technique.
        Physics of Fluids A: Fluid Dynamics (1989-1993), 4(7), 1510-1520.

    For the RDT-based compression term:
        El Tahry, S. H. (1983).
        k-epsilon equation for compressible reciprocating engine flows.
        Journal of Energy, 7(4), 345-353.
    \endverbatim

    The default model coefficients are
    \verbatim
        RNGkEpsilonCoeffs
        {
            Cmu         0.0845;
            C1          1.42;
            C2          1.68;
            C3          -0.33;
            sigmak      0.71942;
            sigmaEps    0.71942;
            eta0        4.38;
            beta        0.012;
        }
    \endverbatim

SourceFiles
    RNGkEpsilon.C

\*---------------------------------------------------------------------------*/

#ifndef RNGkEpsilon_H
#define RNGkEpsilon_H

#include "RASModel.H"
#include "eddyViscosity.H"

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

namespace Foam
{
namespace RASModels
{

/*---------------------------------------------------------------------------*\
                           Class RNGkEpsilon Declaration
\*---------------------------------------------------------------------------*/

template<class BasicTurbulenceModel>
class RNGkEpsilon
:
    public eddyViscosity<RASModel<BasicTurbulenceModel>>
{
    // Private Member Functions

        //- No copy construct
        RNGkEpsilon(const RNGkEpsilon&) = delete;

        //- No copy assignment
        void operator=(const RNGkEpsilon&) = delete;


protected:

    // Protected data

        // Model coefficients

            dimensionedScalar Cmu_;
            dimensionedScalar C1_;
            dimensionedScalar C2_;
            dimensionedScalar C3_;
            dimensionedScalar sigmak_;
            dimensionedScalar sigmaEps_;
            dimensionedScalar eta0_;
            dimensionedScalar beta_;


        // Fields

            volScalarField k_;
            volScalarField epsilon_;


    // Protected Member Functions

        virtual void correctNut();
        virtual tmp<fvScalarMatrix> kSource() const;
        virtual tmp<fvScalarMatrix> epsilonSource() const;


public:

    typedef typename BasicTurbulenceModel::alphaField alphaField;
    typedef typename BasicTurbulenceModel::rhoField rhoField;
    typedef typename BasicTurbulenceModel::transportModel transportModel;


    //- Runtime type information
    TypeName("RNGkEpsilon");


    // Constructors

        //- Construct from components
        RNGkEpsilon
        (
            const alphaField& alpha,
            const rhoField& rho,
            const volVectorField& U,
            const surfaceScalarField& alphaRhoPhi,
            const surfaceScalarField& phi,
            const transportModel& transport,
            const word& propertiesName = turbulenceModel::propertiesName,
            const word& type = typeName
        );


    //- Destructor
    virtual ~RNGkEpsilon() = default;


    // Member Functions

        //- Re-read model coefficients if they have changed
        virtual bool read();

        //- Return the effective diffusivity for k
        tmp<volScalarField> DkEff() const
        {
            return tmp<volScalarField>
            (
                new volScalarField
                (
                    "DkEff",
                    (this->nut_/sigmak_ + this->nu())
                )
            );
        }

        //- Return the effective diffusivity for epsilon
        tmp<volScalarField> DepsilonEff() const
        {
            return tmp<volScalarField>
            (
                new volScalarField
                (
                    "DepsilonEff",
                    (this->nut_/sigmaEps_ + this->nu())
                )
            );
        }

        //- Return the turbulence kinetic energy
        virtual tmp<volScalarField> k() const
        {
            return k_;
        }

        //- Return the turbulence kinetic energy dissipation rate
        virtual tmp<volScalarField> epsilon() const
        {
            return epsilon_;
        }

        //- Return the (estimated) specific dissipation rate
        virtual tmp<volScalarField> omega() const
        {
            return tmp<volScalarField>::New
            (
                IOobject
                (
                    IOobject::groupName("omega", this->alphaRhoPhi_.group()),
                    this->runTime_.timeName(),
                    this->mesh_
                ),
                epsilon_/(Cmu_*k_)
            );
        }

        //- Solve the turbulence equations and correct the turbulence viscosity
        virtual void correct();
};


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

} // End namespace RASModels
} // End namespace Foam

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

#ifdef NoRepository
    #include "RNGkEpsilon.C"
#endif

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

#endif

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