CFD Online Discussion Forums - OF-2.2.x: Can't access cellZones in parallel run

Hi,

I was writing a small functionObject to monitor p and U values in selected cellSets. The sets are created with topoSet and then converted to cellZones with setsToZones. It does all run well in a serial simulation, but not if I try to run it in parallel using mpirun. It will then just think that the cellZones are empty.

What I did before, when having to handle cellZones, is that I executed the topoSet and setsToZones in every processor directory explicitly, which seemed to solve the problems. This time that did not solve the problem.

I have a guess that just one processor is looped over in my functionObject and not all of them, and that the processors don't communicate in this cellZone loop, as they would in a loop over a volume field.

Code:

const fvMesh& mesh(refCast<const fvMesh>(obr_));

const volScalarField& p(mesh.lookupObject<volScalarField>("p"));

const volVectorField& U(mesh.lookupObject<volVectorField>("U"));

const cellZoneMesh& cellZones(mesh.cellZones());



forAll(cellZones, zoneID)

        {

            const word& zoneName(cellZones.names()[zoneID]);

            const labelUList& cellZone(cellZones[zoneID]);



            scalar pSumme(0);

            scalar UXSumme(0);

            scalar UYSumme(0);

            scalar UZSumme(0);

            scalar count(0);



            forAll(cellZone, i)

            {

                pSumme += p[cellZone[i]];

                UXSumme += U[cellZone[i]].x();

                UYSumme += U[cellZone[i]].y();

                UZSumme += U[cellZone[i]].z();

                count++;

            }

            

            scalar pAvg = pSumme/(count+VSMALL);

            scalar UXAvg = UXSumme/(count+VSMALL);

            scalar UYAvg = UYSumme/(count+VSMALL);

            scalar UZAvg = UZSumme/(count+VSMALL);



            Info<< nl << zoneName << ": " << pAvg << tab 

                << UXAvg << tab << UYAvg << tab

                << UZAvg << nl << endl;

}

The problem is that my cellZone, which the parallel run gives me output for, seems to be empty and I did an "Info<< cellZone.size()" which verified that. So how can I access all the cellZones, when running in parallel.

The method I chose isn't the most elegant one, but I don't know how I can average in an easier way and I don't know if that even matters, because the cellZones can't be found.

Anyone having an idea?