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::MaxwellianThermal<CloudType>::correct
(
typename CloudType::parcelType& p,
const wallPolyPatch& wpp
)
{
vector& U = p.U();
scalar& Ei = p.Ei();
label typeId = p.typeId();
label wppIndex = wpp.index();
label wppLocalFace = wpp.whichFace(p.face());
vector nw = p.normal();
nw /= mag(nw);
// Normal velocity magnitude
scalar U_dot_nw = U & nw;
// Wall tangential velocity (flow direction)
vector Ut = U - U_dot_nw*nw;
CloudType& cloud(this->owner());
Random& rndGen(cloud.rndGen());
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.scalar01()),
U.y()*(0.8 + 0.2*rndGen.scalar01()),
U.z()*(0.8 + 0.2*rndGen.scalar01())
);
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();
scalar iDof = cloud.constProps(typeId).internalDegreesOfFreedom();
U =
sqrt(physicoChemical::k.value()*T/mass)
*(
rndGen.GaussNormal()*tw1
+ rndGen.GaussNormal()*tw2
- sqrt(-2.0*log(max(1 - rndGen.scalar01(), VSMALL)))*nw
);
U += cloud.boundaryU().boundaryField()[wppIndex][wppLocalFace];
Ei = cloud.equipartitionInternalEnergy(T, iDof);
}
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.scalar01())
{
// 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.scalar01()),
U.y()*(0.8 + 0.2*rndGen.scalar01()),
U.z()*(0.8 + 0.2*rndGen.scalar01())
);
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.scalarNormal()*tw1
+ rndGen.scalarNormal()*tw2
- sqrt(-2.0*log(max(1 - rndGen.scalar01(), 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;
}
}
}
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;
}
}
void Foam::LarsenBorgnakkeVariableHardSphere<CloudType>::collide
(
typename CloudType::parcelType& pP,
typename CloudType::parcelType& pQ
)
{
CloudType& cloud(this->owner());
label typeIdP = pP.typeId();
label typeIdQ = pQ.typeId();
vector& UP = pP.U();
vector& UQ = pQ.U();
scalar& EiP = pP.Ei();
scalar& EiQ = pQ.Ei();
Random& rndGen(cloud.rndGen());
scalar inverseCollisionNumber = 1/relaxationCollisionNumber_;
// Larsen Borgnakke internal energy redistribution part. Using the serial
// application of the LB method, as per the INELRS subroutine in Bird's
// DSMC0R.FOR
scalar preCollisionEiP = EiP;
scalar preCollisionEiQ = EiQ;
direction iDofP = cloud.constProps(typeIdP).internalDegreesOfFreedom();
direction iDofQ = cloud.constProps(typeIdQ).internalDegreesOfFreedom();
scalar omegaPQ =
0.5
*(
cloud.constProps(typeIdP).omega()
+ cloud.constProps(typeIdQ).omega()
);
scalar mP = cloud.constProps(typeIdP).mass();
scalar mQ = cloud.constProps(typeIdQ).mass();
scalar mR = mP*mQ/(mP + mQ);
vector Ucm = (mP*UP + mQ*UQ)/(mP + mQ);
scalar cRsqr = magSqr(UP - UQ);
scalar availableEnergy = 0.5*mR*cRsqr;
scalar ChiB = 2.5 - omegaPQ;
if (iDofP > 0)
{
if (inverseCollisionNumber > rndGen.scalar01())
{
availableEnergy += preCollisionEiP;
if (iDofP == 2)
{
scalar energyRatio = 1.0 - pow(rndGen.scalar01(), (1.0/ChiB));
EiP = energyRatio*availableEnergy;
}
else
{
scalar ChiA = 0.5*iDofP;
EiP = energyRatio(ChiA, ChiB)*availableEnergy;
}
availableEnergy -= EiP;
}
}
if (iDofQ > 0)
{
if (inverseCollisionNumber > rndGen.scalar01())
{
availableEnergy += preCollisionEiQ;
if (iDofQ == 2)
{
scalar energyRatio = 1.0 - pow(rndGen.scalar01(), (1.0/ChiB));
EiQ = energyRatio*availableEnergy;
}
else
{
scalar ChiA = 0.5*iDofQ;
EiQ = energyRatio(ChiA, ChiB)*availableEnergy;
}
availableEnergy -= EiQ;
}
}
// Rescale the translational energy
scalar cR = sqrt(2.0*availableEnergy/mR);
// Variable Hard Sphere collision part
scalar cosTheta = 2.0*rndGen.scalar01() - 1.0;
scalar sinTheta = sqrt(1.0 - cosTheta*cosTheta);
scalar phi = twoPi*rndGen.scalar01();
vector postCollisionRelU =
cR
*vector
(
cosTheta,
sinTheta*cos(phi),
sinTheta*sin(phi)
);
UP = Ucm + postCollisionRelU*mQ/(mP + mQ);
UQ = Ucm - postCollisionRelU*mP/(mP + mQ);
}
bool Foam::StandardWallInteraction<CloudType>::correct
(
typename CloudType::parcelType& p,
const polyPatch& pp,
bool& keepParticle,
const scalar trackFraction,
const tetIndices& tetIs
)
{
vector& U = p.U();
bool& active = p.active();
if (isA<wallPolyPatch>(pp))
{
switch (interactionType_)
{
case PatchInteractionModel<CloudType>::itEscape:
{
scalar dm = p.mass()*p.nParticle();
keepParticle = false;
active = false;
U = vector::zero;
nEscape_++;
massEscape_ += dm;
break;
}
case PatchInteractionModel<CloudType>::itStick:
{
keepParticle = true;
active = false;
U = vector::zero;
nStick_++;
break;
}
case PatchInteractionModel<CloudType>::itRebound:
{
keepParticle = true;
active = true;
vector nw;
vector Up;
this->owner().patchData(p, pp, trackFraction, tetIs, nw, Up);
// Calculate motion relative to patch velocity
U -= Up;
scalar Un = U & nw;
vector Ut = U - Un*nw;
if (Un > 0)
{
U -= (1.0 + e_)*Un*nw;
}
U -= mu_*Ut;
// Return velocity to global space
U += Up;
break;
}
default:
{
FatalErrorIn
(
"bool StandardWallInteraction<CloudType>::correct"
"("
"typename CloudType::parcelType&, "
"const polyPatch&, "
"bool& keepParticle, "
"const scalar, "
"const tetIndices&"
") const"
) << "Unknown interaction type "
<< this->interactionTypeToWord(interactionType_)
<< "(" << interactionType_ << ")" << endl
<< abort(FatalError);
}
}
return true;
}
return false;
}
bool Foam::LocalInteraction<CloudType>::correct
(
typename CloudType::parcelType& p,
const polyPatch& pp,
bool& keepParticle,
const scalar trackFraction,
const tetIndices& tetIs
)
{
label patchI = patchData_.applyToPatch(pp.index());
if (patchI >= 0)
{
vector& U = p.U();
bool& active = p.active();
typename PatchInteractionModel<CloudType>::interactionType it =
this->wordToInteractionType
(
patchData_[patchI].interactionTypeName()
);
switch (it)
{
case PatchInteractionModel<CloudType>::itEscape:
{
scalar dm = p.mass()*p.nParticle();
keepParticle = false;
active = false;
U = vector::zero;
nEscape_[patchI]++;
massEscape_[patchI] += dm;
if (writeFields_)
{
label pI = pp.index();
label fI = pp.whichFace(p.face());
massEscape().boundaryField()[pI][fI] += dm;
}
break;
}
case PatchInteractionModel<CloudType>::itStick:
{
scalar dm = p.mass()*p.nParticle();
keepParticle = true;
active = false;
U = vector::zero;
nStick_[patchI]++;
massStick_[patchI] += dm;
if (writeFields_)
{
label pI = pp.index();
label fI = pp.whichFace(p.face());
massStick().boundaryField()[pI][fI] += dm;
}
break;
}
case PatchInteractionModel<CloudType>::itRebound:
{
keepParticle = true;
active = true;
vector nw;
vector Up;
this->owner().patchData(p, pp, trackFraction, tetIs, nw, Up);
// Calculate motion relative to patch velocity
U -= Up;
scalar Un = U & nw;
vector Ut = U - Un*nw;
if (Un > 0)
{
U -= (1.0 + patchData_[patchI].e())*Un*nw;
}
U -= patchData_[patchI].mu()*Ut;
// Return velocity to global space
U += Up;
break;
}
default:
{
FatalErrorIn
(
"bool LocalInteraction<CloudType>::correct"
"("
"typename CloudType::parcelType&, "
"const polyPatch&, "
"bool&, "
"const scalar, "
"const tetIndices&"
") const"
) << "Unknown interaction type "
<< patchData_[patchI].interactionTypeName()
<< "(" << it << ") for patch "
<< patchData_[patchI].patchName()
<< ". Valid selections are:" << this->interactionTypeNames_
<< endl << abort(FatalError);
}
}
return true;
}
return false;
}