Foam::forceSuSp Foam::PlessisMasliyahDragForce<CloudType>::calcCoupled ( const typename CloudType::parcelType& p, const scalar dt, const scalar mass, const scalar Re, const scalar muc ) const { scalar alphac(alphac_[p.cell()]); scalar cbrtAlphap(pow(1.0 - alphac, 1.0/3.0)); scalar A = 26.8*pow3(alphac) /( sqr(cbrtAlphap) *(1.0 - cbrtAlphap) *sqr(1.0 - sqr(cbrtAlphap)) + SMALL ); scalar B = sqr(alphac) /sqr(1.0 - sqr(cbrtAlphap)); return forceSuSp ( vector::zero, (mass/p.rho()) *(A*(1.0 - alphac) + B*Re)*muc/(alphac*sqr(p.d())) ); }
Foam::forceSuSp Foam::DPMDragModels::ErgunWenYu<CloudType>::calcCoupled ( const typename CloudType::parcelType& p, const scalar dt, const scalar mass, const scalar Re, const scalar muc ) const { scalar alphac(alphac_[p.cell()]); if (alphac < 0.8) { return forceSuSp ( vector::zero, (mass/p.rho()) *((150.0*(1.0 - alphac) + 1.75*Re)*muc/(alphac*sqr(p.d()))) ); } else { return forceSuSp ( vector::zero, (mass/p.rho()) *0.75*CdRe(alphac*Re)*muc*pow(alphac, -2.65)/sqr(p.d()) ); } }
Foam::vector Foam::DampingModels::Relaxation<CloudType>::velocityCorrection ( typename CloudType::parcelType& p, const scalar deltaT ) const { const tetIndices tetIs(p.cell(), p.tetFace(), p.tetPt(), this->owner().mesh()); const scalar x = deltaT*oneByTimeScaleAverage_->interpolate(p.position(), tetIs); const vector u = uAverage_->interpolate(p.position(), tetIs); return (u - p.U())*x/(x + 2.0); }
Foam::forceSuSp Foam::BrownianMotionForce<CloudType>::calcCoupled ( const typename CloudType::parcelType& p, const scalar dt, const scalar mass, const scalar Re, const scalar muc ) const { forceSuSp value(vector::zero, 0.0); const scalar dp = p.d(); const scalar Tc = p.Tc(); const scalar eta = rndGen_.sample01<scalar>(); const scalar alpha = 2.0*lambda_/dp; const scalar cc = 1.0 + alpha*(1.257 + 0.4*exp(-1.1/alpha)); const scalar sigma = physicoChemical::sigma.value(); scalar f = 0.0; if (turbulence_) { const label cellI = p.cell(); const volScalarField& k = *kPtr_; const scalar kc = k[cellI]; const scalar Dp = sigma*Tc*cc/(3*mathematical::pi*muc*dp); f = eta/mass*sqrt(2.0*sqr(kc)*sqr(Tc)/(Dp*dt)); } else { const scalar rhoRatio = p.rho()/p.rhoc(); const scalar s0 = 216*muc*sigma*Tc/(sqr(mathematical::pi)*pow5(dp)*(rhoRatio)*cc); f = eta*sqrt(mathematical::pi*s0/dt); } const scalar sqrt2 = sqrt(2.0); for (label i = 0; i < 3; i++) { const scalar x = rndGen_.sample01<scalar>(); const scalar eta = sqrt2*erfInv(2*x - 1.0); value.Su()[i] = mass*f*eta; } return value; }
Foam::forceSuSp Foam::WenYuDragForce<CloudType>::calcCoupled ( const typename CloudType::parcelType& p, const scalar dt, const scalar mass, const scalar Re, const scalar muc ) const { scalar alphac(alphac_[p.cell()]); return forceSuSp ( vector::zero, (mass/p.rho()) *0.75*CdRe(alphac*Re)*muc*pow(alphac, -2.65)/(alphac*sqr(p.d())) ); }
Foam::forceSuSp Foam::BrownianMotionForce<CloudType>::calcCoupled ( const typename CloudType::parcelType& p, const typename CloudType::parcelType::trackingData& td, const scalar dt, const scalar mass, const scalar Re, const scalar muc ) const { forceSuSp value(Zero, 0.0); const scalar dp = p.d(); const scalar Tc = td.Tc(); const scalar alpha = 2.0*lambda_/dp; const scalar cc = 1.0 + alpha*(1.257 + 0.4*exp(-1.1/alpha)); // Boltzmann constant const scalar kb = physicoChemical::k.value(); scalar f = 0; if (turbulence_) { const label celli = p.cell(); const volScalarField& k = *kPtr_; const scalar kc = k[celli]; const scalar Dp = kb*Tc*cc/(3*mathematical::pi*muc*dp); f = sqrt(2.0*sqr(kc)*sqr(Tc)/(Dp*dt)); } else { const scalar s0 = 216*muc*kb*Tc/(sqr(mathematical::pi)*pow5(dp)*sqr(p.rho())*cc); f = mass*sqrt(mathematical::pi*s0/dt); } // To generate a cubic distribution (3 independent directions) : // const scalar sqrt2 = sqrt(2.0); // for (direction dir = 0; dir < vector::nComponents; dir++) // { // const scalar x = rndGen_.sample01<scalar>(); // const scalar eta = sqrt2*erfInv(2*x - 1.0); // value.Su()[dir] = f*eta; // } // To generate a spherical distribution: Random& rnd = this->owner().rndGen(); const scalar theta = rnd.scalar01()*twoPi; const scalar u = 2*rnd.scalar01() - 1; const scalar a = sqrt(1 - sqr(u)); const vector dir(a*cos(theta), a*sin(theta), u); value.Su() = f*mag(rnd.scalarNormal())*dir; return value; }