[aeroBassti]

Hi there,



Unfortunately, I am an early beginner with programming in OpenFOAM.

I would like to get a for each time step a value (here U) averaged over all cells in the (inner) mesh that are at positions x>0 (or other values). Is it possible to split the field into two areas: before (x<0) and after the object (x>0) and output each value via

"Info << UposX.weightedAverage(mesh.V()).value() << endl;
Info << UnegX.weightedAverage(mesh.V()).value() << endl;"

?

[olesen]

For this particular requirement do it yourself will be the best approach. Build two quantities during the loop, followed by any reductions. For example,

scalar volNeg = 0, volPos = 0;
for (label celli=0; celli < mesh.nCells(); ++celli) 
{
    const scalar vol = mesh.V()[celli];
    if (mesh.C()[celli].x() >= 0)
    {
        volPos += vol;
    }
    else
    {
        volNeg += vol;
    } 
}
reduce(volNeg, sumOp<scalar>());
reduce(volPos, sumOp<scalar>());

If you are going to do this a lot (or for several different fields) you can also build a labelList with the cell ids where x>=0 and another for the others. Then use a UIndirectList for walking the fields.