[KlasJ]

Hi Roman,

Perhaps you have already solved this issue, but if not perhaps this could be of help.

My experience with multidomain cases is that it is much easier to use a manual decomposition. What I usually do is to produce a list of all the cells for all the regions in my simulation. Then I supply the lists (one per region) to the manual mode of decompasePar. The decomposeParDict would read:

numberOfSubdomains N;
method          manual;
manualCoeffs
{
        dataFile "cellDecomposition";
}
distributed no;

and the cellDecomposition would look something like:

FoamFile
{
    version     2.0;
    format      ascii;
    class       labelList;
    location    "constant";
    object      cellDecomposition;
}

ZZ
(
X
....
X
)

where ZZ are the number of cells for this region and X are the processor numbers where you want this cell to be placed.

Now, the interesting part is how you produce such lists. When the problems have very specific geometries or specific interfaces I often prefer to determine the processor boundaries somewhat manual. For example, if you have repeating geometry (like a set of fuel pins in a reactor) the point of automatic decomposition is much smaller.

I use a utility application to perform the splitting using topoSets. The application reads some splitting coordinates from a dictionary and then computes the processor for each of the cells. If you are interested I could share this small application.

Best regards,

Klas