void Foam::LambertWall<CloudType>::evaluatePendularWall ( typename CloudType::parcelType& p, const point& site, const WallSiteData<vector>& data, scalar pREff ) const { const scalar& st = this->surfaceTension(); const scalar& ca = this->contactAngle(); const scalar& lf = this->liqFrac(); const scalar& vis = this->viscosity(); const scalar& ms = this->minSep(); scalar Vtot = lf*(p.Vliq()); vector r_PW = p.position() - site; vector U_PW = p.U() - data.wallData(); scalar r_PW_mag = mag(r_PW); scalar normalOverlapMag = pREff - r_PW_mag; scalar S = -normalOverlapMag; vector rHat_PW = r_PW/(r_PW_mag + VSMALL); // Normal force scalar capMag = 4*mathematical::pi*pREff*st*cos(ca)/ (1+max(S, 0)*sqrt(mathematical::pi*pREff/Vtot)); //Info << "the value of capMag is " << capMag << endl; //Info << " the value of overlapMag S is " << S << endl; //Info << " the volume of Vtot is " << Vtot << endl; scalar Svis = max(pREff*ms, S); scalar etaN = 6*mathematical::pi*vis*pREff*pREff/Svis; vector fN_PW = (-capMag - etaN*(U_PW & rHat_PW)) * rHat_PW; p.f() += fN_PW; vector UT_PW = U_PW - (U_PW & rHat_PW)*rHat_PW - ((pREff*p.omega()) ^ rHat_PW); scalar etaT = 6*mathematical::pi*vis*pREff*(8./15.*log(pREff/Svis) + 0.9588); vector fT_PW = -etaT * UT_PW; p.f() += fT_PW; p.torque() += (pREff*-rHat_PW) ^ fT_PW; }
void Foam::PairSpringSliderDashpot<CloudType>::evaluatePair ( typename CloudType::parcelType& pA, typename CloudType::parcelType& pB ) const { vector r_AB = (pA.position() - pB.position()); scalar dAEff = pA.d(); if (useEquivalentSize_) { dAEff *= cbrt(pA.nParticle()*volumeFactor_); } scalar dBEff = pB.d(); if (useEquivalentSize_) { dBEff *= cbrt(pB.nParticle()*volumeFactor_); } scalar r_AB_mag = mag(r_AB); scalar normalOverlapMag = 0.5*(dAEff + dBEff) - r_AB_mag; if (normalOverlapMag > 0) { //Particles in collision vector rHat_AB = r_AB/(r_AB_mag + VSMALL); vector U_AB = pA.U() - pB.U(); // Effective radius scalar R = 0.5*dAEff*dBEff/(dAEff + dBEff); // Effective mass scalar M = pA.mass()*pB.mass()/(pA.mass() + pB.mass()); scalar kN = (4.0/3.0)*sqrt(R)*Estar_; scalar etaN = alpha_*sqrt(M*kN)*pow025(normalOverlapMag); // Normal force vector fN_AB = rHat_AB *(kN*pow(normalOverlapMag, b_) - etaN*(U_AB & rHat_AB)); // Cohesion force if (cohesion_) { fN_AB += -cohesionEnergyDensity_ *overlapArea(dAEff/2.0, dBEff/2.0, r_AB_mag) *rHat_AB; } pA.f() += fN_AB; pB.f() += -fN_AB; vector USlip_AB = U_AB - (U_AB & rHat_AB)*rHat_AB + (pA.omega() ^ (dAEff/2*-rHat_AB)) - (pB.omega() ^ (dBEff/2*rHat_AB)); scalar deltaT = this->owner().mesh().time().deltaTValue(); vector& tangentialOverlap_AB = pA.collisionRecords().matchPairRecord ( pB.origProc(), pB.origId() ).collisionData(); vector& tangentialOverlap_BA = pB.collisionRecords().matchPairRecord ( pA.origProc(), pA.origId() ).collisionData(); vector deltaTangentialOverlap_AB = USlip_AB*deltaT; tangentialOverlap_AB += deltaTangentialOverlap_AB; tangentialOverlap_BA += -deltaTangentialOverlap_AB; scalar tangentialOverlapMag = mag(tangentialOverlap_AB); if (tangentialOverlapMag > VSMALL) { scalar kT = 8.0*sqrt(R*normalOverlapMag)*Gstar_; scalar etaT = etaN; // Tangential force vector fT_AB; if (kT*tangentialOverlapMag > mu_*mag(fN_AB)) { // Tangential force greater than sliding friction, // particle slips fT_AB = -mu_*mag(fN_AB)*USlip_AB/mag(USlip_AB); tangentialOverlap_AB = vector::zero; tangentialOverlap_BA = vector::zero; } else { fT_AB = -kT*tangentialOverlapMag *tangentialOverlap_AB/tangentialOverlapMag - etaT*USlip_AB; } pA.f() += fT_AB; pB.f() += -fT_AB; pA.torque() += (dAEff/2*-rHat_AB) ^ fT_AB; pB.torque() += (dBEff/2*rHat_AB) ^ -fT_AB; } } }
void Foam::WallLocalSpringSliderDashpot<CloudType>::evaluateWall ( typename CloudType::parcelType& p, const point& site, const WallSiteData<vector>& data, scalar pREff ) const { // wall patch index label wPI = patchMap_[data.patchIndex()]; // data for this patch scalar Estar = Estar_[wPI]; scalar Gstar = Gstar_[wPI]; scalar alpha = alpha_[wPI]; scalar b = b_[wPI]; scalar mu = mu_[wPI]; vector r_PW = p.position() - site; vector U_PW = p.U() - data.wallData(); scalar normalOverlapMag = max(pREff - mag(r_PW), 0.0); vector rHat_PW = r_PW/(mag(r_PW) + VSMALL); scalar kN = (4.0/3.0)*sqrt(pREff)*Estar; scalar etaN = alpha*sqrt(p.mass()*kN)*pow025(normalOverlapMag); vector fN_PW = rHat_PW *(kN*pow(normalOverlapMag, b) - etaN*(U_PW & rHat_PW)); p.f() += fN_PW; vector USlip_PW = U_PW - (U_PW & rHat_PW)*rHat_PW + (p.omega() ^ (pREff*-rHat_PW)); scalar deltaT = this->owner().mesh().time().deltaTValue(); vector& tangentialOverlap_PW = p.collisionRecords().matchWallRecord(-r_PW, pREff).collisionData(); tangentialOverlap_PW += USlip_PW*deltaT; scalar tangentialOverlapMag = mag(tangentialOverlap_PW); if (tangentialOverlapMag > VSMALL) { scalar kT = 8.0*sqrt(pREff*normalOverlapMag)*Gstar; scalar etaT = etaN; // Tangential force vector fT_PW; if (kT*tangentialOverlapMag > mu*mag(fN_PW)) { // Tangential force greater than sliding friction, // particle slips fT_PW = -mu*mag(fN_PW)*USlip_PW/mag(USlip_PW); tangentialOverlap_PW = vector::zero; } else { fT_PW = -kT*tangentialOverlapMag *tangentialOverlap_PW/tangentialOverlapMag - etaT*USlip_PW; } p.f() += fT_PW; p.torque() += (pREff*-rHat_PW) ^ fT_PW; } }