MixedDiffuseSpecular.C

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    Copyright (C) 2011-2017 OpenFOAM Foundation
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License
    This file is part of OpenFOAM.
 
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#include "MixedDiffuseSpecular.H"
 
// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
template<class CloudType>
Foam::MixedDiffuseSpecular<CloudType>::MixedDiffuseSpecular
(
    const dictionary& dict,
    CloudType& cloud
)
:
    WallInteractionModel<CloudType>(dict, cloud, typeName),
    diffuseFraction_(this->coeffDict().getScalar("diffuseFraction"))
{}
 
 
// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
template<class CloudType>
Foam::MixedDiffuseSpecular<CloudType>::~MixedDiffuseSpecular()
{}
 
 
// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
template<class CloudType>
void Foam::MixedDiffuseSpecular<CloudType>::correct
(
    typename CloudType::parcelType& p
)
{
    vector& U = p.U();
 
    scalar& Ei = p.Ei();
 
    label typeId = p.typeId();
 
    const label wppIndex = p.patch();
 
    const polyPatch& wpp = p.mesh().boundaryMesh()[wppIndex];
 
    label wppLocalFace = wpp.whichFace(p.face());
 
    const vector nw = p.normal();
 
    // Normal velocity magnitude
    scalar U_dot_nw = U & nw;
 
    CloudType& cloud(this->owner());
 
    Random& rndGen = cloud.rndGen();
 
    if (diffuseFraction_ > rndGen.sample01<scalar>())
    {
        // Diffuse reflection
 
        // Wall tangential velocity (flow direction)
        vector Ut = U - U_dot_nw*nw;
 
        while (mag(Ut) < SMALL)
        {
            // If the incident velocity is parallel to the face normal, no
            // tangential direction can be chosen.  Add a perturbation to the
            // incoming velocity and recalculate.
            U = vector
            (
                U.x()*(0.8 + 0.2*rndGen.sample01<scalar>()),
                U.y()*(0.8 + 0.2*rndGen.sample01<scalar>()),
                U.z()*(0.8 + 0.2*rndGen.sample01<scalar>())
            );
 
            U_dot_nw = U & nw;
 
            Ut = U - U_dot_nw*nw;
        }
 
        // Wall tangential unit vector
        vector tw1 = Ut/mag(Ut);
 
        // Other tangential unit vector
        vector tw2 = nw^tw1;
 
        scalar T = cloud.boundaryT().boundaryField()[wppIndex][wppLocalFace];
 
        scalar mass = cloud.constProps(typeId).mass();
 
        direction iDof = cloud.constProps(typeId).internalDegreesOfFreedom();
 
        U =
            sqrt(physicoChemical::k.value()*T/mass)
           *(
                rndGen.GaussNormal<scalar>()*tw1
              + rndGen.GaussNormal<scalar>()*tw2
              - sqrt(-2.0*log(max(1 - rndGen.sample01<scalar>(), VSMALL)))*nw
            );
 
        U += cloud.boundaryU().boundaryField()[wppIndex][wppLocalFace];
 
        Ei = cloud.equipartitionInternalEnergy(T, iDof);
    }
    else
    {
        // Specular reflection
 
        if (U_dot_nw > 0.0)
        {
            U -= 2.0*U_dot_nw*nw;
        }
    }
 
}
 
 
// ************************************************************************* //