/*---------------------------------------------------------------------------*\
  ==  == ====== ====   ====    |
                    \\     ||  | Multiphase Code Repository by HZDR
  ======   //   ||  || ===//   | Website: https://doi.org/10.14278/rodare.767
  ||  ||  //    ||  // || \\   | License: GPL-3.0-or-later
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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
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    Multiphase Code Repository by HZDR is free software: you can redistribute
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Class
    Foam::addonFilmSurfaceVelocityFvPatchVectorField

Description
    Film surface velocity boundary condition

    Evaluates the surface velocity from the shear imposed by the neighbouring
    phases velocity using either a simple drag model based on the difference
    between the phases and film velocities multiplied by the coefficient \c Cs
    or if \c Cs is set to 0, the fluid viscous shear stress.

    The simple model might be used in preference to the fluid viscous shear
    stress model in order to provide some means to include the drag enhancing
    effect of surface ripples, rivulets etc. in the film surface.

    The model supports multiple phases and allows different Cs values for each.
    The contribution to the shear stress of every phase is weighted by its
    volume fraction. The total shear is calculated as the weighted sum of the
    contributions given by each phase.

Usage
    \table
        Property     | Description                    | Required | Default value
        phases       | List of names of all phases    | yes      |
        Cs.phaseName | Drag coefficient per phase     | no       | 0
    \endtable

    Example of boundary condition specification:
    \verbatim
    <patchName>
    {
        type           addonFilmSurfaceVelocity;
        libs           ("libaddonIsothermalFilm.so");
        phases         (air liquid);
        Cs.air         0.005;
        Cs.liquid      0;
        value          $internalField;
    }
    \endverbatim

See also
    Foam::mixedFvPatchField
    Foam::filmSurfaceVelocityFvPatchVectorField

SourceFiles
    addonFilmSurfaceVelocityFvPatchVectorField.C

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

#ifndef addonFilmSurfaceVelocityFvPatchVectorField_H
#define addonFilmSurfaceVelocityFvPatchVectorField_H

#include "mixedFvPatchFields.H"

namespace Foam
{
/*---------------------------------------------------------------------------*\
          Class addonFilmSurfaceVelocityFvPatchVectorField Declaration
\*---------------------------------------------------------------------------*/

class addonFilmSurfaceVelocityFvPatchVectorField
:
    public mixedFvPatchVectorField
{
    // Private Data

        //- List of all phase names
        const wordList phaseNames_;

        //- List of drag coefficients for each phase
        scalarList Cs_;


public:

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

   // Constructors

        //- Construct from patch, internal field and dictionary
        addonFilmSurfaceVelocityFvPatchVectorField
        (
            const fvPatch&,
            const DimensionedField<vector, volMesh>&,
            const dictionary&
        );

        //- Construct by mapping onto a new patch
        addonFilmSurfaceVelocityFvPatchVectorField
        (
            const addonFilmSurfaceVelocityFvPatchVectorField&,
            const fvPatch&,
            const DimensionedField<vector, volMesh>&,
            const fieldMapper&
        );

        //- Disallow copy without setting internal field reference
        addonFilmSurfaceVelocityFvPatchVectorField
        (
            const addonFilmSurfaceVelocityFvPatchVectorField&
        ) = delete;

        //- Copy constructor setting internal field reference
        addonFilmSurfaceVelocityFvPatchVectorField
        (
            const addonFilmSurfaceVelocityFvPatchVectorField&,
            const DimensionedField<vector, volMesh>&
        );

        //- Construct and return a clone setting internal field reference
        virtual tmp<fvPatchVectorField> clone
        (
            const DimensionedField<vector, volMesh>& iF
        ) const
        {
            return tmp<fvPatchVectorField>
            (
                new addonFilmSurfaceVelocityFvPatchVectorField
                (
                    *this,
                    iF
                )
            );
        }


    // Member Functions

        //- Update the coefficients associated with the patch field
        virtual void updateCoeffs();

        //- Write
        virtual void write(Ostream&) const;
};


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

} // End namespace Foam

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

#endif

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