/*---------------------------------------------------------------------------*\
  ==  == ====== ====   ====    |
                    \\     ||  | Multiphase Code Repository by HZDR
  ======   //   ||  || ===//   | Website: https://doi.org/10.14278/rodare.767
  ||  ||  //    ||  // || \\   | License: GPL-3.0-or-later
  ==  == ====== ====   ==  ==  |
-------------------------------------------------------------------------------
License
    This file is part of the Multiphase Code Repository by HZDR.

    Copyright (C) 2025 by Helmholtz-Zentrum Dresden-Rossendorf e.V. (HZDR),
    Website: https://hzdr.de

    Multiphase Code Repository by HZDR is based on the free software for
    computational fluid dynamics (CFD) from the OpenFOAM Foundation.
    Copyright (C) 2025 by OpenFOAM Foundation, Website: https://openfoam.org

    If you are interested in which files are original OpenFOAM Foundation
    files, which OpenFOAM Foundation files were modified, and which files were
    newly created, see FILES.md.

    Multiphase Code Repository by HZDR 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.

    Multiphase Code Repository by HZDR 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 the Multiphase Code Repository by HZDR. If not, see
    <http://www.gnu.org/licenses/>.

Class
    Foam::dragModels::StrubeljTiselj

Description
    Numerical drag for handling of resolved interfaces in multi-fluid model

    \verbatim
        Strubelj, L., & Tiselj, I. (2011).
        Two-fluid model with interface sharpening.
        International Journal for Numerical Methods in Engineering, 85, 575-590.
    \endverbatim

Usage
    \table
        Property      | Description            | Required | Default value
        Tau           | Time scale ratio       | yes      | -
        residualAlpha | Residual fraction for phases | no | phase.residualAlpha
    \endtable

    Example usage:
    \verbatim
    gas_segregatedWith_liquid
    {
        type            StrubeljTiselj;

        Tau             1e8;

        residualAlpha   1e-6;
    }
    \endverbatim

SourceFiles
    StrubeljTiselj.C

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

#ifndef StrubeljTiselj_H
#define StrubeljTiselj_H

#include "dragModel.H"
#include "segregatedPhaseInterface.H"

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

namespace Foam
{
namespace dragModels
{

/*---------------------------------------------------------------------------*\
                       Class StrubeljTiselj Declaration
\*---------------------------------------------------------------------------*/

class StrubeljTiselj
:
    public dragModel
{
    // Private Data

        //- Interface
        const segregatedPhaseInterface interface_;

        //- Ratio of physical time step to relaxation time
        const dimensionedScalar tau_;

        //- Residual value for phase fraction of phase 1
        const dimensionedScalar residualAlpha1_;

        //- Residual value for phase fraction of phase 2
        const dimensionedScalar residualAlpha2_;


public:

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


    // Constructors

        //- Construct from a dictionary and an interface
        StrubeljTiselj
        (
            const dictionary& dict,
            const phaseInterface& interface,
            const bool registerObject
        );


    //- Destructor
    virtual ~StrubeljTiselj();


    // Member Functions

        //- Return the drag coefficient K as a scalar
        //  used in the momentum equations
        //    ddt(alpha1*rho1*U1) + ... = ... K*(U1-U2)
        //    ddt(alpha2*rho2*U2) + ... = ... K*(U2-U1)
        virtual tmp<volScalarField> K() const;

        //- Return the drag coefficient Kf
        //  used in the face-momentum equations
        virtual tmp<surfaceScalarField> Kf() const;
};


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

} // End namespace dragModels
} // End namespace Foam

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

#endif

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