[Cyp]

Hi!

I wonder what is the correct code form to modify the BC during runs.

I know that for a fixedValue BC the "==" sign is required to overwrite the orginal BC. For example:

phiS.boundaryField()[patchID]== phib.boundaryField()[patchID];

Now, if I want to modify a fixedGradient, it seems to me that "==" doesn't overwrite the orginal BC but "=" does. My piece of code is the following:

    fixedGradientFvPatchScalarField& gradpPatch=refCast<fixedGradientFvPatchScalarField>(p.boundaryField()[patchID]); 
    scalarField& gradpField =  gradpPatch.gradient();
    gradpField = fluxP;

Do you have an explanation ?

Best regards,
Cyp