Dear all,

I want to define the Marangoni stress at a liquid free surface boundary. Marangoni stress is written as follows: del(sigma)=d(sigma)/dT*del(T).

In FLUENT's UDF, we can use cell variations macros to define del(T). For example, dT/dx=C_T_G(c,t)[0].But for face variations, FLUENT don't define corresponding macros, i.e., there is not F_T_G(c,t)[0].

So, I want to know how to define del(T) at a face.

In addition, I want to know how to define cell variations macros in cylindrical coordinates. For example, dT/dr=?

Thank you in advance!

Who can ask my questions?

Thanks ahead!