Maxwell.H

Go to the documentation of this file.

/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Copyright (C) 2016-2026 OpenFOAM Foundation
     \\/     M anipulation  |
-------------------------------------------------------------------------------
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 3 of the License, or
    (at your option) any later version.
 
    OpenFOAM 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 OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
Class
    Foam::laminarModels::Maxwell
 
Description
    Generalised Maxwell model for viscoelasticity using the upper-convected time
    derivative of the stress tensor with support for multiple modes.
 
    See http://en.wikipedia.org/wiki/Upper-convected_Maxwell_model
        http://en.wikipedia.org/wiki/Generalised_Maxwell_model
 
    The model includes an additional viscosity (nu) from the viscosity
    model from which it is instantiated, which makes it equivalent to
    the Oldroyd-B model for the case of an incompressible viscosity
    model (where nu is non-zero).
    See https://en.wikipedia.org/wiki/Oldroyd-B_model
 
    Reference:
    \verbatim
        Wiechert, E. (1889). Ueber elastische Nachwirkung.
        (Doctoral dissertation, Hartungsche buchdr.).
 
        Wiechert, E. (1893).
        Gesetze der elastischen Nachwirkung für constante Temperatur.
        Annalen der Physik, 286(11), 546-570.
 
        Amoreira, L. J., & Oliveira, P. J. (2010).
        Comparison of different formulations for the numerical calculation
        of unsteady incompressible viscoelastic fluid flow.
        Adv. Appl. Math. Mech, 4, 483-502.
    \endverbatim
 
SourceFiles
    Maxwell.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef Maxwell_H
#define Maxwell_H
 
#include "laminarModel.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace laminarModels
{
 
/*---------------------------------------------------------------------------*\
                           Class Maxwell Declaration
\*---------------------------------------------------------------------------*/
 
template<class BasicMomentumTransportModel>
class Maxwell
:
    public laminarModel<BasicMomentumTransportModel>
{
    // Private Member Functions
 
        //- Return the source term for the momentum equation
        template<class RhoFieldType>
        tmp<fvVectorMatrix> DivDevTau
        (
            const RhoFieldType& rho,
            volVectorField& U
        ) const;
 
 
protected:
 
    // Protected data
 
        // Model coefficients
 
            //- Mode coefficients dictionary
            dictionary modeCoefficients_;
 
            //- Number of modes
            label nModes_;
 
            //- Mode non-Newtonian viscosities
            PtrList<dimensionedScalar> nuM_;
 
            //- Mode time-scales
            PtrList<dimensionedScalar> lambdas_;
 
            //- Sum of mode non-Newtonian viscosities
            dimensionedScalar nuMSum_;
 
 
        // Fields
 
            //- Single or mode sum viscoelastic stress
            volSymmTensorField sigma_;
 
            //- Mode viscoelastic stresses
            PtrList<volSymmTensorField> sigmas_;
 
 
    // Protected Member Functions
 
        //- Read a coefficient for all modes and return as a list
        PtrList<dimensionedScalar> readModeCoefficients
        (
            const word& name,
            const dimensionSet& dims
        ) const;
 
        //- Read a coefficient for all modes and return as a list
        PtrList<dimensionedScalar> readModeCoefficients
        (
            const word& type,
            const word& name,
            const dimensionSet& dims
        ) const;
 
        //- Return the sum of the given list of mode viscosities
        dimensionedScalar sumNuM(const PtrList<dimensionedScalar>& nuM) const;
 
        //- Return the effective viscosity
        tmp<volScalarField> nu0() const
        {
            return this->nu() + nuMSum_;
        }
 
        virtual tmp<fvSymmTensorMatrix> sigmaSource
        (
            const label modei,
            volSymmTensorField& sigma
        ) const;
 
 
public:
 
    typedef typename BasicMomentumTransportModel::alphaField alphaField;
    typedef typename BasicMomentumTransportModel::rhoField rhoField;
 
 
    //- Runtime type information
    TypeName("Maxwell");
 
 
    // Constructors
 
        //- Construct from components
        Maxwell
        (
            const alphaField& alpha,
            const rhoField& rho,
            const volVectorField& U,
            const surfaceScalarField& alphaRhoPhi,
            const surfaceScalarField& phi,
            const viscosity& viscosity,
            const word& type = typeName
        );
 
 
    //- Destructor
    virtual ~Maxwell()
    {}
 
 
    // Member Functions
 
        //- Read model coefficients if they have changed
        virtual bool read();
 
        //- Return the effective viscosity, i.e. the laminar viscosity
        virtual tmp<volScalarField> nuEff() const;
 
        //- Return the effective viscosity on patch
        virtual tmp<scalarField> nuEff(const label patchi) const;
 
        //- Return the effective surface stress
        virtual tmp<surfaceVectorField> devTau() const;
 
        //- Return the source term for the momentum equation
        virtual tmp<fvVectorMatrix> divDevTau(volVectorField& U) const;
 
        //- Return the source term for the momentum equation
        virtual tmp<fvVectorMatrix> divDevTau
        (
            const volScalarField& rho,
            volVectorField& U
        ) const;
 
        //- The Maxwell stress is not predicted
        virtual void predict()
        {}
 
        //- Correct the Maxwell stress
        virtual void correct();
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace laminarModels
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#ifdef NoRepository
    #include "Maxwell.C"
#endif
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //