curvatureSeparation.H

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License
    This file is part of OpenFOAM.

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Class
    Foam::regionModels::areaSurfaceFilmModels::curvatureSeparation

Description
    Curvature film separation model

    Assesses film curvature via the mesh geometry and calculates a force
    balance of the form:

        F_sum = F_inertial + F_body + F_surface

    If F_sum < 0, the film separates. Similarly, if F_sum > 0 the film will
    remain attached.

    Reference:
    \verbatim
        Owen, I., & Ryley, D. J. (1985).
        The flow of thin liquid films around corners.
        International journal of multiphase flow, 11(1), 51-62.
    \endverbatim

Usage
    Example of the model specification:
    \verbatim
    injectionModels
    (
        curvatureSeparation
    );

    curvatureSeparationCoeffs
    {
        // Optional entries
        deltaByR1Min        <scalar>;
        definedPatchRadii   <scalar>;
        fThreshold          <scalar>;
        minInvR1            <scalar>;

        // Inherited entries
        ...
    }
    \endverbatim

    where the entries mean:
    \table
      Property       | Description                    | Type  | Reqd | Deflt
      deltaByR1Min   | Minimum gravity driven film thickness | scalar | no | 0
      definedPatchRadii | Patch radius            i   | scalar | no | 0
      fThreshold     | Threshold force for separation | scalar | no | 1e-8
      minInvR1       | Minimum inv R1 for separation  | scalar | no | 5
    \endtable

    The inherited entries are elaborated in:
      - \link injectionModel.H \endlink

SourceFiles
    curvatureSeparation.C

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

#ifndef curvatureSeparation_H
#define curvatureSeparation_H

#include "injectionModel.H"

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

namespace Foam
{
namespace regionModels
{
namespace areaSurfaceFilmModels
{

/*---------------------------------------------------------------------------*\
                   Class curvatureSeparation Declaration
\*---------------------------------------------------------------------------*/

class curvatureSeparation
:
    public injectionModel
{
    // Private Member Functions

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

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


protected:

    // Protected Data

        //- Gradient of surface normals
        areaTensorField gradNHat_;

        //- Minimum gravity driven film thickness (non-dimensionalised delta/R1)
        scalar deltaByR1Min_;

        //- Patch radius
        scalar definedPatchRadii_;

        //- Magnitude of gravity vector
        scalar magG_;

        //- Direction of gravity vector
        vector gHat_;

        //- Threshold force for separation
        scalar fThreshold_;

        //- Minimum inv R1 for separation
        scalar minInvR1_;


    // Protected Member Functions

        //- Calculate local (inverse) radius of curvature
        tmp<areaScalarField> calcInvR1
        (
            const areaVectorField& U,
            const scalarField& calcCosAngle
        ) const;

        //- Calculate the cosine of the angle between gravity vector and
        //- cell out flow direction
        tmp<scalarField> calcCosAngle(const edgeScalarField& phi) const;


public:

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


    // Constructors

        //- Construct from surface film model
        curvatureSeparation
        (
            liquidFilmBase& film,
            const dictionary& dict
        );


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


    // Member Functions

        // Evolution

            //- Correct
            virtual void correct
            (
                scalarField& availableMass,
                scalarField& massToInject,
                scalarField& diameterToInject
            );
};


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

} // End namespace areaSurfaceFilmModels
} // End namespace regionModels
} // End namespace Foam

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

#endif

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