// Construct from components
Foam::lagrangianWriter::lagrangianWriter
(
const vtkMesh& vMesh,
const bool binary,
const fileName& fName,
const word& cloudName,
const bool dummyCloud
)
:
vMesh_(vMesh),
binary_(binary),
fName_(fName),
cloudName_(cloudName),
os_(fName.c_str())
{
const fvMesh& mesh = vMesh_.mesh();
// Write header
writeFuns::writeHeader(os_, binary_, mesh.time().caseName());
os_ << "DATASET POLYDATA" << std::endl;
if (dummyCloud)
{
nParcels_ = 0;
os_ << "POINTS " << nParcels_ << " float" << std::endl;
}
else
{
Cloud<passiveParticle> parcels(mesh, cloudName_, false);
nParcels_ = parcels.size();
os_ << "POINTS " << nParcels_ << " float" << std::endl;
DynamicList<floatScalar> partField(3*parcels.size());
forAllConstIter(Cloud<passiveParticle>, parcels, elmnt)
{
writeFuns::insert(elmnt().position(), partField);
}
writeFuns::write(os_, binary_, partField);
}
void stochasticDispersionRAS::disperseParcels() const
{
const scalar cps = 0.16432;
scalar dt = spray_.runTime().deltaT().value();
const volScalarField& k = turbulence().k();
//volVectorField gradk = fvc::grad(k);
const volScalarField& epsilon = turbulence().epsilon();
const volVectorField& U = spray_.U();
for
(
spray::iterator elmnt = spray_.begin();
elmnt != spray_.end();
++elmnt
)
{
label celli = elmnt().cell();
scalar UrelMag = mag(elmnt().U() - U[celli] - elmnt().Uturb());
scalar Tturb = min
(
k[celli]/epsilon[celli],
cps*pow(k[celli], 1.5)/epsilon[celli]/(UrelMag + SMALL)
);
// parcel is perturbed by the turbulence
if (dt < Tturb)
{
elmnt().tTurb() += dt;
if (elmnt().tTurb() > Tturb)
{
elmnt().tTurb() = 0.0;
scalar sigma = sqrt(2.0*k[celli]/3.0);
vector dir = 2.0*spray_.rndGen().vector01() - vector::one;
dir /= mag(dir) + SMALL;
// numerical recipes... Ch. 7. Random Numbers...
scalar x1,x2;
scalar rsq = 10.0;
while((rsq > 1.0) || (rsq == 0.0))
{
x1 = 2.0*spray_.rndGen().scalar01() - 1.0;
x2 = 2.0*spray_.rndGen().scalar01() - 1.0;
rsq = x1*x1 + x2*x2;
}
scalar fac = sqrt(-2.0*log(rsq)/rsq);
fac *= mag(x1);
elmnt().Uturb() = sigma*fac*dir;
}
}
else
{
elmnt().tTurb() = GREAT;
elmnt().Uturb() = vector::zero;
}
}
}
void Foam::stochasticDispersionRAS::disperseParcels() const
{
const scalar cps = 0.16432;
const vector one(1.0, 1.0, 1.0);
scalar dt = spray_.runTime().deltaTValue();
const volScalarField& k = turbulence().k();
// volVectorField gradk(fvc::grad(k));
const volScalarField& epsilon = turbulence().epsilon();
const volVectorField& U = spray_.U();
forAllIter(spray, spray_, elmnt)
{
const label cellI = elmnt().cell();
scalar UrelMag = mag(elmnt().U() - U[cellI] - elmnt().Uturb());
scalar Tturb = min
(
k[cellI]/epsilon[cellI],
cps*pow(k[cellI], 1.5)/epsilon[cellI]/(UrelMag + SMALL)
);
// parcel is perturbed by the turbulence
if (dt < Tturb)
{
elmnt().tTurb() += dt;
if (elmnt().tTurb() > Tturb)
{
elmnt().tTurb() = 0.0;
scalar sigma = sqrt(2.0*k[cellI]/3.0);
vector dir = 2.0*spray_.rndGen().sample01<vector>() - one;
dir /= mag(dir) + SMALL;
// numerical recipes... Ch. 7. Random Numbers...
scalar x1,x2;
scalar rsq = 10.0;
while (rsq > 1.0 || rsq == 0.0)
{
x1 = 2.0*spray_.rndGen().sample01<scalar>() - 1.0;
x2 = 2.0*spray_.rndGen().sample01<scalar>() - 1.0;
rsq = x1*x1 + x2*x2;
}
scalar fac = sqrt(-2.0*log(rsq)/rsq);
fac *= mag(x1);
elmnt().Uturb() = sigma*fac*dir;
}
}
else
{
elmnt().tTurb() = GREAT;
elmnt().Uturb() = vector::zero;
}
}
}
void gradientDispersionRAS::disperseParcels() const
{
const scalar cps = 0.16432;
scalar dt = spray_.runTime().deltaT().value();
const volScalarField& k = turbulence().k();
volVectorField gradk = fvc::grad(k);
const volScalarField& epsilon = turbulence().epsilon();
const volVectorField& U = spray_.U();
for
(
spray::iterator elmnt = spray_.begin();
elmnt != spray_.end();
++elmnt
)
{
label celli = elmnt().cell();
scalar UrelMag = mag(elmnt().U() - U[celli] - elmnt().Uturb());
scalar Tturb = min
(
k[celli]/epsilon[celli],
cps*pow(k[celli], 1.5)/epsilon[celli]/(UrelMag + SMALL)
);
// parcel is perturbed by the turbulence
if (dt < Tturb)
{
elmnt().tTurb() += dt;
if (elmnt().tTurb() > Tturb)
{
elmnt().tTurb() = 0.0;
scalar sigma = sqrt(2.0*k[celli]/3.0);
vector dir = -gradk[celli]/(mag(gradk[celli]) + SMALL);
// numerical recipes... Ch. 7. Random Numbers...
scalar x1 = 0.0;
scalar x2 = 0.0;
scalar rsq = 10.0;
while((rsq > 1.0) || (rsq == 0.0))
{
x1 = 2.0*spray_.rndGen().scalar01() - 1.0;
x2 = 2.0*spray_.rndGen().scalar01() - 1.0;
rsq = x1*x1 + x2*x2;
}
scalar fac = sqrt(-2.0*log(rsq)/rsq);
// in 2D calculations the -grad(k) is always
// away from the axis of symmetry
// This creates a 'hole' in the spray and to
// prevent this we let x1 be both negative/positive
if (spray_.twoD())
{
fac *= x1;
}
else
{
fac *= mag(x1);
}
elmnt().Uturb() = sigma*fac*dir;
}
}
else
{
elmnt().tTurb() = GREAT;
elmnt().Uturb() = vector::zero;
}
}
}
