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;
}
}
