thixotropicViscosity.H

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Class
    Foam::regionModels::surfaceFilmModels::thixotropicViscosity
 
Description
    Thixotropic viscosity model based on the evolution of the structural
    parameter \f$ \lambda \f$:
 
        \f[
            \lambda = a(1 - \lambda)^b - c \lambda \dot{\gamma}^d
        \f]
 
    The viscosity is then calculated using the expression
 
        \f[
            \mu = \frac{\mu_{\infty}}{{1 - K \lambda}^2}
        \f]
 
    Where the parameter K is given by:
 
        \f[
            K = 1 - \sqrt{\frac{\mu_{\infty}}{\mu_{0}}}
        \f]
 
    Here:
    \vartable
        \lambda         | structural parameter
        a               | model coefficient
        b               | model coefficient
        c               | model coefficient
        d               | model coefficient
        \dot{\gamma}    | stress rate [1/s]
        \mu_{0}         | limiting viscosity when \f$ \lambda = 1 \f$
        \mu_{\infty}    | limiting viscosity when \f$ \lambda = 0 \f$
    \endvartable
 
    Reference:
    \verbatim
        Barnes H A, 1997.  Thixotropy - a review.  J. Non-Newtonian Fluid
        Mech 70, pp 1-33
    \endverbatim
 
SourceFiles
    thixotropicViscosity.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef thixotropicViscosity_H
#define thixotropicViscosity_H
 
#include "filmViscosityModel.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace regionModels
{
namespace surfaceFilmModels
{
 
/*---------------------------------------------------------------------------*\
                    Class thixotropicViscosity Declaration
\*---------------------------------------------------------------------------*/
 
class thixotropicViscosity
:
    public filmViscosityModel
{
    // Private member functions
 
        //- No copy construct
        thixotropicViscosity(const thixotropicViscosity&) = delete;
 
        //- No copy assignment
        void operator=(const thixotropicViscosity&) = delete;
 
 
protected:
 
    // Protected data
 
        //- Model `a' coefficient
        dimensionedScalar a_;
 
        //- Model `b' coefficient
        dimensionedScalar b_;
 
        //- Model `d' coefficient
        dimensionedScalar d_;
 
        //- Model `c' coefficient (read after d since dims depend on d value)
        dimensionedScalar c_;
 
        //- Limiting viscosity when lambda = 1
        dimensionedScalar mu0_;
 
        //- Limiting viscosity when lambda = 0
        dimensionedScalar muInf_;
 
        //- Model coefficient
        dimensionedScalar K_;
 
        //- Structural parameter
        //  0 = freestream value (most liquid)
        //  1 = fully built (most solid)
        volScalarField lambda_;
 
 
public:
 
    //- Runtime type information
    TypeName("thixotropic");
 
 
    // Constructors
 
        //- Construct from surface film model
        thixotropicViscosity
        (
            surfaceFilmRegionModel& film,
            const dictionary& dict,
            volScalarField& mu
        );
 
 
    //- Destructor
    virtual ~thixotropicViscosity();
 
 
    // Member Functions
 
        //- Correct
        virtual void correct
        (
            const volScalarField& p,
            const volScalarField& T
        );
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace surfaceFilmModels
} // End namespace regionModels
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //