/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 1991-2009 OpenCFD Ltd.
     \\/     M anipulation  |
-------------------------------------------------------------------------------
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 2 of the License, or (at your
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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    You should have received a copy of the GNU General Public License
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\*---------------------------------------------------------------------------*/

#include "nutUSpaldingWallFunctionFvPatchScalarField.H"
#include "RASModel.H"
#include "fvPatchFieldMapper.H"
#include "volFields.H"
#include "addToRunTimeSelectionTable.H"

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

namespace Foam
{
namespace incompressible
{
namespace RASModels
{

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

tmp<scalarField> nutUSpaldingWallFunctionFvPatchScalarField::calcNut() const
{
    const label patchI = patch().index();

    const RASModel& rasModel = db().lookupObject<RASModel>("RASProperties");
    const fvPatchVectorField& Uw = rasModel.U().boundaryField()[patchI];
    const scalarField magGradU = mag(Uw.snGrad());
    const scalarField& nuw = rasModel.nu().boundaryField()[patchI];

    return max(scalar(0), sqr(calcUTau(magGradU))/magGradU - nuw);
}


tmp<scalarField> nutUSpaldingWallFunctionFvPatchScalarField::calcUTau
(
    const scalarField& magGradU
) const
{
    const RASModel& rasModel = db().lookupObject<RASModel>("RASProperties");
    const scalarField& y = rasModel.y()[patch().index()];

    const fvPatchVectorField& Uw =
        rasModel.U().boundaryField()[patch().index()];
    const scalarField magUp = mag(Uw.patchInternalField() - Uw);

    const scalarField& nuw = rasModel.nu().boundaryField()[patch().index()];
    const scalarField& nutw = *this;

    tmp<scalarField> tuTau(new scalarField(patch().size(), 0.0));
    scalarField& uTau = tuTau();

    forAll(uTau, facei)
    {
        scalar magUpara = magUp[facei];

        scalar ut = sqrt((nutw[facei] + nuw[facei])*magGradU[facei]);

        if (ut > VSMALL)
        {
            int iter = 0;
            scalar err = GREAT;

            do
            {
                scalar kUu = min(kappa_*magUpara/ut, 50);
                scalar fkUu = exp(kUu) - 1 - kUu*(1 + 0.5*kUu);

                scalar f =
                    - ut*y[facei]/nuw[facei]
                    + magUpara/ut
                    + 1/E_*(fkUu - 1.0/6.0*kUu*sqr(kUu));

                scalar df =
                    y[facei]/nuw[facei]
                  + magUpara/sqr(ut)
                  + 1/E_*kUu*fkUu/ut;

                scalar uTauNew = ut + f/df;
                err = mag((ut - uTauNew)/ut);
                ut = uTauNew;

            } while (ut > VSMALL && err > 0.01 && ++iter < 10);
            uTau[facei] = max(0.0, ut);
        }
    }

    return tuTau;
}


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

nutUSpaldingWallFunctionFvPatchScalarField::
nutUSpaldingWallFunctionFvPatchScalarField
(
    const fvPatch& p,
    const DimensionedField<scalar, volMesh>& iF
)
:
    nutkWallFunctionFvPatchScalarField(p, iF)
{}


nutUSpaldingWallFunctionFvPatchScalarField::
nutUSpaldingWallFunctionFvPatchScalarField
(
    const nutUSpaldingWallFunctionFvPatchScalarField& ptf,
    const fvPatch& p,
    const DimensionedField<scalar, volMesh>& iF,
    const fvPatchFieldMapper& mapper
)
:
    nutkWallFunctionFvPatchScalarField(ptf, p, iF, mapper)
{}


nutUSpaldingWallFunctionFvPatchScalarField::
nutUSpaldingWallFunctionFvPatchScalarField
(
    const fvPatch& p,
    const DimensionedField<scalar, volMesh>& iF,
    const dictionary& dict
)
:
    nutkWallFunctionFvPatchScalarField(p, iF, dict)
{}


nutUSpaldingWallFunctionFvPatchScalarField::
nutUSpaldingWallFunctionFvPatchScalarField
(
    const nutUSpaldingWallFunctionFvPatchScalarField& wfpsf
)
:
    nutkWallFunctionFvPatchScalarField(wfpsf)
{}


nutUSpaldingWallFunctionFvPatchScalarField::
nutUSpaldingWallFunctionFvPatchScalarField
(
    const nutUSpaldingWallFunctionFvPatchScalarField& wfpsf,
    const DimensionedField<scalar, volMesh>& iF
)
:
    nutkWallFunctionFvPatchScalarField(wfpsf, iF)
{}


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

tmp<scalarField> nutUSpaldingWallFunctionFvPatchScalarField::yPlus() const
{
    const label patchI = patch().index();

    const RASModel& rasModel = db().lookupObject<RASModel>("RASProperties");
    const scalarField& y = rasModel.y()[patchI];
    const fvPatchVectorField& Uw = rasModel.U().boundaryField()[patchI];
    const scalarField& nuw = rasModel.nu().boundaryField()[patchI];

    return y*calcUTau(mag(Uw.snGrad()))/nuw;
}


void nutUSpaldingWallFunctionFvPatchScalarField::write(Ostream& os) const
{
    fvPatchField<scalar>::write(os);
    writeLocalEntries(os);
    writeEntry("value", os);
}


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

makePatchTypeField
(
    fvPatchScalarField,
    nutUSpaldingWallFunctionFvPatchScalarField
);

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

} // End namespace RASModels
} // End namespace incompressible
} // End namespace Foam

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