/*---------------------------------------------------------------------------*\
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    Copyright (C) 2018-2020 OpenFOAM Foundation
    Copyright (C) 2020 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.

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    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.

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#include "HerschelBulkley.H"
#include "volgpuFields.H"
#include "addToRunTimeSelectionTable.H"

// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //

namespace Foam
{
namespace laminarModels
{
namespace generalizedNewtonianViscosityModels
{
    defineTypeNameAndDebug(HerschelBulkley, 0);

    addToRunTimeSelectionTable
    (
        generalizedNewtonianViscosityModel,
        HerschelBulkley,
        dictionary
    );
}
}
}


// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //

Foam::laminarModels::generalizedNewtonianViscosityModels::HerschelBulkley::
HerschelBulkley
(
    const dictionary& viscosityProperties
)
:
    generalizedNewtonianViscosityModel(viscosityProperties),
    HerschelBulkleyCoeffs_
    (
        viscosityProperties.optionalSubDict(typeName + "Coeffs")
    ),
    n_("n", dimless, HerschelBulkleyCoeffs_),
    tau0_("tau0", dimViscosity/dimTime, HerschelBulkleyCoeffs_)
{}


// * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //

bool Foam::laminarModels::generalizedNewtonianViscosityModels::
HerschelBulkley::read
(
    const dictionary& viscosityProperties
)
{
    generalizedNewtonianViscosityModel::read(viscosityProperties);

    HerschelBulkleyCoeffs_ =
        viscosityProperties.optionalSubDict(typeName + "Coeffs");

    HerschelBulkleyCoeffs_.readEntry("n", n_);
    HerschelBulkleyCoeffs_.readEntry("tau0", tau0_);

    return true;
}


Foam::tmp<Foam::volScalargpuField>
Foam::laminarModels::generalizedNewtonianViscosityModels::HerschelBulkley::
nu
(
    const volScalargpuField& nu0,
    const volScalargpuField& strainRate
) const
{
    const dimensionedScalar tone("tone", dimTime, 1);
    const dimensionedScalar rtone("rtone", dimless/dimTime, 1);

    return
    (
        min
        (
            nu0,
            (tau0_ + nu0*rtone*pow(tone*strainRate, n_))
           /max
            (
                strainRate,
                dimensionedScalar("SMALL", dimless/dimTime, VSMALL)
            )
        )
    );
}


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