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Cartesian subCelling of collision cell implemented. Need to check the impact on performance and results

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This commit is contained in:
graham
2009-03-10 17:41:25 +00:00
parent 542e05ce7f
commit dc0d41f816
1 changed files with 82 additions and 5 deletions
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87
src/lagrangian/dsmc/clouds/Templates/DsmcCloud/DsmcCloud.C
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@ -224,6 +224,9 @@ void Foam::DsmcCloud<ParcelType>::collisions()
{
buildCellOccupancy();
// Temporary storage for subCells
List<DynamicList<label> > subCells(8);
scalar deltaT = mesh_.time().deltaT().value();
label collisionCandidates = 0;
@ -238,6 +241,37 @@ void Foam::DsmcCloud<ParcelType>::collisions()
if (nC > 1)
{
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Assign particles to one of 8 Cartesian subCells
// Clear temporary lists
forAll(subCells, i)
{
subCells[i].clear();
}
// Inverse addressing specifying which subCell a parcel is in
List<label> whichSubCell(cellParcels.size());
const point& cC = mesh_.cellCentres()[celli];
forAll(cellParcels, i)
{
ParcelType* p = cellParcels[i];
vector relPos = p->position() - cC;
label subCell =
pos(relPos.x()) + 2*pos(relPos.y()) + 4*pos(relPos.z());
subCells[subCell].append(i);
whichSubCell[i] = subCell;
}
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
scalar sigmaTcRMax = sigmaTcRMax_[celli];
scalar selectedPairs = collisionSelectionRemainder_[celli]
@ -252,17 +286,60 @@ void Foam::DsmcCloud<ParcelType>::collisions()
for(label c = 0; c < nCandidates; c++)
{
// Select the first collision candidate
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// subCell candidate selection procedure
// Select the first collision candidate
label candidateP = rndGen_.integer(0, nC-1);
label candidateQ = rndGen_.integer(0, nC-1);
// Declare the second collision candidate
label candidateQ = -1;
// If the same candidate is chosen, choose again
while(candidateP == candidateQ)
List<label> subCellPs = subCells[whichSubCell[candidateP]];
label nSC = subCellPs.size();
if (nSC > 1)
{
candidateQ = rndGen_.integer(0, nC-1);
// If there are two or more particle in a subCell, choose
// another from the same cell. If the same candidate is
// chosen, choose again.
do
{
candidateQ = subCellPs[rndGen_.integer(0, nSC-1)];
} while(candidateP == candidateQ);
}
else
{
// Select a possible second collision candidate from the
// whole cell. If the same candidate is chosen, choose
// again.
do
{
candidateQ = rndGen_.integer(0, nC-1);
} while(candidateP == candidateQ);
}
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// uniform candidate selection procedure
// // Select the first collision candidate
// label candidateP = rndGen_.integer(0, nC-1);
// // Select a possible second collision candidate
// label candidateQ = rndGen_.integer(0, nC-1);
// // If the same candidate is chosen, choose again
// while(candidateP == candidateQ)
// {
// candidateQ = rndGen_.integer(0, nC-1);
// }
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
ParcelType* parcelP = cellParcels[candidateP];
ParcelType* parcelQ = cellParcels[candidateQ];