Hi, thanks for the answer, but I still have a question. How should I define the mesh for the CFD problem to address this kind of issue? In this case, I need to solve for q” through the line in order to estimate the h coefficient (please remember that the boundary condition dictates constant temperature). I’ve also run the simulation in double precision, but the outcome remains the same. Also because I would like to know which of them is the right one (iso_05 or iso_049)