/*---------------------------------------------------------------------------*\
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    \\  /    A nd           | Copyright held by original author
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-------------------------------------------------------------------------------
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 2 of the License, or (at your
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    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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    You should have received a copy of the GNU General Public License
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Class
    threePhaseInterfaceProperties

Description
    Properties to aid interFoam :
    1. Correct the alpha boundary condition for dynamic contact angle.
    2. Calculate interface curvature.

SourceFiles
    threePhaseInterfaceProperties.C

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

#ifndef threePhaseInterfaceProperties_H
#define threePhaseInterfaceProperties_H

#include "threePhaseMixture.H"
#include "surfaceFields.H"

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

namespace Foam
{

/*---------------------------------------------------------------------------*\
              Class threePhaseInterfaceProperties Declaration
\*---------------------------------------------------------------------------*/

class threePhaseInterfaceProperties
{
    // Private data

        const threePhaseMixture& mixture_;

        //- Compression coefficient
        scalar cAlpha_;

        //- Surface tension 1-2
        dimensionedScalar sigma12_;

        //- Surface tension 1-3
        dimensionedScalar sigma13_;

        //- Stabilisation for normalisation of the interface normal
        const dimensionedScalar deltaN_;

        surfaceScalarField nHatf_;
        volScalarField K_;


    // Private Member Functions

        //- Disallow default bitwise copy construct and assignment
        threePhaseInterfaceProperties(const threePhaseInterfaceProperties&);
        void operator=(const threePhaseInterfaceProperties&);

        //- Correction for the boundary condition on the unit normal nHat on
        //  walls to produce the correct contact dynamic angle
        //  calculated from the component of U parallel to the wall
        void correctContactAngle
        (
            surfaceVectorField::GeometricBoundaryField& nHat
        ) const;

        //- Re-calculate the interface curvature
        void calculateK();


public:

    //- Conversion factor for degrees into radians
    static const scalar convertToRad;


    // Constructors

        //- Construct from volume fraction field alpha and IOdictionary
        threePhaseInterfaceProperties(const threePhaseMixture& mixture);


    // Member Functions

        scalar cAlpha() const
        {
            return cAlpha_;
        }

        const dimensionedScalar& deltaN() const
        {
            return deltaN_;
        }

        const surfaceScalarField& nHatf() const
        {
            return nHatf_;
        }

        const volScalarField& K() const
        {
            return K_;
        }

        tmp<volScalarField> sigma() const
        {
            volScalarField limitedAlpha2 = max(mixture_.alpha2(), scalar(0));
            volScalarField limitedAlpha3 = max(mixture_.alpha3(), scalar(0));

            return
                (limitedAlpha2*sigma12_ + limitedAlpha3*sigma13_)
               /(limitedAlpha2 + limitedAlpha3 + SMALL);
        }

        tmp<volScalarField> sigmaK() const
        {
            return sigma()*K_;
        }

        void correct()
        {
            calculateK();
        }
};


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

} // End namespace Foam

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

#endif

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