StochasticDispersionRAS.C

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#include "StochasticDispersionRAS.H"
#include "constants.H"
#include "standardNormal.H"
 
using namespace Foam::constant::mathematical;
 
// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
template<class CloudType>
Foam::StochasticDispersionRAS<CloudType>::StochasticDispersionRAS
(
    const dictionary& dict,
    CloudType& owner
)
:
    DispersionRASModel<CloudType>(dict, owner)
{}
 
 
template<class CloudType>
Foam::StochasticDispersionRAS<CloudType>::StochasticDispersionRAS
(
    const StochasticDispersionRAS<CloudType>& dm
)
:
    DispersionRASModel<CloudType>(dm)
{}
 
 
// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
template<class CloudType>
Foam::StochasticDispersionRAS<CloudType>::~StochasticDispersionRAS()
{}
 
 
// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
template<class CloudType>
Foam::vector Foam::StochasticDispersionRAS<CloudType>::update
(
    const scalar dt,
    const label celli,
    const vector& U,
    const vector& Uc,
    vector& UTurb,
    scalar& tTurb
)
{
    randomGenerator& rndGen = this->owner().rndGen();
    distributions::standardNormal& stdNormal = this->owner().stdNormal();
 
    const scalar cps = 0.16432;
 
    const scalar k = this->kPtr_->primitiveField()[celli];
    const scalar epsilon =
        this->epsilonPtr_->primitiveField()[celli] + rootVSmall;
 
    const scalar UrelMag = mag(U - Uc - UTurb);
 
    const scalar tTurbLoc =
        min(k/epsilon, cps*pow(k, 1.5)/epsilon/(UrelMag + small));
 
 
    // Parcel is perturbed by the turbulence
    if (dt < tTurbLoc)
    {
        tTurb += dt;
 
        if (tTurb > tTurbLoc)
        {
            tTurb = 0;
 
            const scalar sigma = sqrt(2*k/3.0);
 
            // Calculate a random direction dir distributed uniformly
            // in spherical coordinates
 
            const scalar theta = rndGen.scalar01()*twoPi;
            const scalar u = 2*rndGen.scalar01() - 1;
 
            const scalar a = sqrt(1 - sqr(u));
            const vector dir(a*cos(theta), a*sin(theta), u);
 
            UTurb = sigma*mag(stdNormal.sample())*dir;
        }
    }
    else
    {
        tTurb = great;
        UTurb = Zero;
    }
 
    return Uc + UTurb;
}
 
 
// ************************************************************************* //