I have added the groovy boundary conditions on the temperature at the free surface to calculate the radiative heat transfer. However, when I calculate the case using this boundary condition, the temperature along the free surface is not shown as expected. I have added the slides and related files to this post.

I met the same problem when I used coded mixed BC to define the temperature distribution(Gaussian) outside the liquid bridge along the free surface. If I put "value," it reads well. Once I put "gradient," the temperature is not shown as expected. (Gaussian profile at the free surface)       So, in my opinion, the ambient temperature may not be defined correctly in the boundary condition.       I feel appreciate it if you could check my boundary condition whether there is something to modify. Thank you very much.