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);
}
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;
}
Foam::forceSuSp Foam::PressureGradientForce<CloudType>::calcCoupled
(
const typename CloudType::parcelType& p,
const scalar dt,
const scalar mass,
const scalar Re,
const scalar muc
) const
{
forceSuSp value(Zero, 0.0);
vector DUcDt =
DUcDtInterp().interpolate(p.position(), p.currentTetIndices());
value.Su() = mass*p.rhoc()/p.rho()*DUcDt;
return value;
}
Foam::forceSuSp Foam::LiftForce<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);
vector curlUc =
curlUcInterp().interpolate(p.position(), p.currentTetIndices());
scalar Cl = this->Cl(p, curlUc, Re, muc);
value.Su() = mass/p.rho()*p.d()/2.0*p.rhoc()*Cl*((p.Uc() - p.U())^curlUc);
return value;
}
Foam::forceSuSp Foam::NonInertialFrameForce<CloudType>::calcNonCoupled
(
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 vector r = p.position() - centreOfRotation_;
value.Su() =
mass
*(
-W_
+ (r ^ omegaDot_)
+ 2.0*(p.U() ^ omega_)
+ (omega_ ^ (r ^ omega_))
);
return value;
}
Foam::forceSuSp Foam::SRFForce<CloudType>::calcNonCoupled
(
const typename CloudType::parcelType& p,
const scalar dt,
const scalar mass,
const scalar Re,
const scalar muc
) const
{
forceSuSp value(Zero, 0.0);
const typename SRF::SRFModel& srf = *srfPtr_;
const vector& omega = srf.omega().value();
const vector& r = p.position();
// Coriolis and centrifugal acceleration terms
value.Su() =
mass*(1.0 - p.rhoc()/p.rho())
*(2.0*(p.U() ^ omega) + (omega ^ (r ^ omega)));
return value;
}
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;
}
}
void Foam::PatchInteractionModel<CloudType>::patchData
(
typename CloudType::parcelType& p,
const polyPatch& pp,
const scalar trackFraction,
const tetIndices& tetIs,
vector& nw,
vector& Up
) const
{
const fvMesh& mesh = this->owner().mesh();
const volVectorField& Ufield =
mesh.objectRegistry::lookupObject<volVectorField>(UName_);
label patchI = pp.index();
label patchFaceI = pp.whichFace(p.face());
vector n = tetIs.faceTri(mesh).normal();
n /= mag(n);
vector U = Ufield.boundaryField()[patchI][patchFaceI];
// Unless the face is rotating, the required normal is n;
nw = n;
if (!mesh.moving())
{
// Only wall patches may have a non-zero wall velocity from
// the velocity field when the mesh is not moving.
if (isA<wallPolyPatch>(pp))
{
Up = U;
}
else
{
Up = vector::zero;
}
}
else
{
vector U00 = Ufield.oldTime().boundaryField()[patchI][patchFaceI];
vector n00 = tetIs.oldFaceTri(mesh).normal();
// Difference in normal over timestep
vector dn = vector::zero;
if (mag(n00) > SMALL)
{
// If the old normal is zero (for example in layer
// addition) then use the current normal, meaning that the
// motion can only be translational, and dn remains zero,
// otherwise, calculate dn:
n00 /= mag(n00);
dn = n - n00;
}
// Total fraction thought the timestep of the motion,
// including stepFraction before the current tracking step
// and the current trackFraction
// i.e.
// let s = stepFraction, t = trackFraction
// Motion of x in time:
// |-----------------|---------|---------|
// x00 x0 xi x
//
// where xi is the correct value of x at the required
// tracking instant.
//
// x0 = x00 + s*(x - x00) = s*x + (1 - s)*x00
//
// i.e. the motion covered by previous tracking portions
// within this timestep, and
//
// xi = x0 + t*(x - x0)
// = t*x + (1 - t)*x0
// = t*x + (1 - t)*(s*x + (1 - s)*x00)
// = (s + t - s*t)*x + (1 - (s + t - s*t))*x00
//
// let m = (s + t - s*t)
//
// xi = m*x + (1 - m)*x00 = x00 + m*(x - x00);
//
// In the same form as before.
scalar m =
p.stepFraction()
+ trackFraction
- (p.stepFraction()*trackFraction);
// When the mesh is moving, the velocity field on wall patches
// will contain the velocity associated with the motion of the
// mesh, in which case it is interpolated in time using m.
// For other patches the face velocity will need to be
// reconstructed from the face centre motion.
const vector& Cf = mesh.faceCentres()[p.face()];
vector Cf00 = mesh.faces()[p.face()].centre(mesh.oldPoints());
if (isA<wallPolyPatch>(pp))
{
Up = U00 + m*(U - U00);
}
else
{
Up = (Cf - Cf00)/this->owner().time().deltaTValue();
}
if (mag(dn) > SMALL)
{
// Rotational motion, nw requires interpolation and a
// rotational velocity around face centre correction to Up
// is required.
nw = n00 + m*dn;
// Cf at tracking instant
vector Cfi = Cf00 + m*(Cf - Cf00);
// Normal vector cross product
vector omega = (n00 ^ n);
scalar magOmega = mag(omega);
// magOmega = sin(angle between unit normals)
// Normalise omega vector by magOmega, then multiply by
// angle/dt to give the correct angular velocity vector.
omega *=
Foam::asin(magOmega)
/(magOmega*this->owner().time().deltaTValue());
// Project position onto face and calculate this position
// relative to the face centre.
vector facePos =
p.position()
- ((p.position() - Cfi) & nw)*nw
- Cfi;
Up += (omega ^ facePos);
}
// No further action is required if the motion is
// translational only, nw and Up have already been set.
}
}