[johnuthin]

Hello,

I have a multiregion solver based on chtmultiregionfoam with 1 solid region and 1 fluid region and arbitrary N neutron physics regions solving another equation set. I have read many posts about meshToMesh but I am not sure if anyone has implemented this structure for a case with multiple solid zones, multiple fluid zones, and multiple extra zones for another physics set.

I want to transfer data between the single solid region and ALL N neutron regions. I then use that data in the neutron physics equations, then transfer other data back to the solid regions. I also do the same for fluid regions. I am mainly interested in transferring just temperature and velocity data. The neutron physics regions are subdivisions of each solid and fluid region. There can be potentially hundreds of individual neutron physics zones based on the problem size. The neutron physics meshes, when combined, also covers the entire fluid+solid domains so all space is covered.

For now, the combination of all neutron region meshes would be consistent with the solid and fluid meshes to ease the data transfer process. I also do not want to extrapolate any data when transferring data from a neutron mesh to the solid mesh. It seems that there are however problems with extrapolation reported here:

Undesired extrapolation when using mapFields/meshToMesh

such that when going from a smaller mesh to a larger mesh, data is extrapolated beyond the smaller mesh boundaries. In my case this would be the data transfer between the neutron (small) mesh and the solid mesh. I havent exactly tested this for my case yet since I am unsure if the implementation would even work.

Is there any way to do what I want using meshToMesh? I thought about creating a loop that looks like the following (slight psuedo-code) but am unsure of how it would work or if it would just cause extrapolation errors and issues. Unfortunately for my problem, I must have many neutron zones. Ideally I would like to have multiple solid or fluid zones and create a generalized solver but I will stick with a signal zone of solids and fluids for now. Here is my proposed pseudo code but I am not sure if it will extrapolate erronously or cause issues going from the smaller neutron meshes to the bigger solid meshes and vice versa.

Solid to neutron meshToMesh:

ptrList<meshToMesh> solidToNeutron(neutronRegions.size());
forAll(neutronRegions, N)
{
meshToMesh solidToNeutron[N] 
(
neutronRegions[N],
solidRegions[0],
interpolationMethod,
procMapMethod,
false
);
}

Then when we want data exchange:

forAll(neutronRegions, N)
{
solidToNeutron[N].mapSrcToTgt(solidTemp[0],  plusEqOp<scalar>(), neutronTemp[N])
}

Then I would repeat similar structure for fluidToNeutron, neutronToFluid, and neutronToSolid at every iteration loop.