[JoeFriend]

Hi, I'm programming a boundary condition for a multi region case (based on compressible::turbulentTemperatureCoupledBaffleMix ed), and I need to access the temperature value of an specific cell in a patch called "maxY".

This is what I've been doing:

const volScalarField& T = db().lookupObject<volScalarField>("T");
const fvMesh& mesh = patch().boundaryMesh().mesh();
label PatchId = mesh.boundaryMesh().findPatchID("maxY");
scalar firstT = T.boundaryField()[PatchId][0]; // face value of the first cell in the patch called "maxY"

I want to assign this value (firstT) to "refGradient" in the BC "turbulentTemperatureCoupledBaffleMixedFvPatchScal arField". The BC compilation is ok, but the solver crashes when it has to solve the temperature fields.

(1) Is there something wrong with the code I wrote?
(2) Does the cell indexes change when decomposing the mesh?
(3) Is it possible to access a field value from an specific cell in a different region? I couldn't find related issues in forums.

I would appreciate any help! Thanks.