[Hanzo]

Hello,

I try to set-up a case using chtMultiRegionFoam.
Later the goal is to include chemistry but at the moment I have a rather simple problem:

In the tutorial for MultiRegionHeater there is always a solid region connected to a fluid region. Therefore velocity at the interface boundaries such as
topAir_to_heater becomes simply (0 0 0).

When I have a case with two fluid zones neighbouring each other, what could be a good BC for velocity, pressure and temperature between these fluid zones? I tried

- BC "calculated": results in the following error
gradientInternalCoeffs cannot be called for a calculatedFvPatchField

- BC "inletOutlet": divergence after a few steps

I also tried some other combinations but I cannot figure out good one.

Thanks for any hints.