Discretization of gradient vector - unstructured mesh
 

Hello,

I have an unstructured triangular mesh that has two different zones (on bottom: zone1, on top: zone2). To impose the boundary condition at the interface, I have these equations:

a [grad(T)*n]1 + b = c [grad(T)*n]2 + d
Tf1 = Tf2 = Tf (interface values)

where the indices 1 and 2 designate the zone and a, b, c and d are constant.

I would like to know how can I descretize the scalar product grad(T)*n at the interface (if it was a structured mesh, I could use (Tf-T1)/ds and (T2-Tf)/ds, but this is not the case) to can impose the value of Tf at the interface.

Thanks in advance

Another question:

Instead of imposing the value of Tf, is there a way to impose directly the flux at both interfaces (interface and interface_SHADOW) even in this situation:

flux(interface) = a [grad(T)*n]1 = c [grad(T)*n]2 + d - b

flux(interface_SHADOW) = c [grad(T)*n]2 = a [grad(T)*n]1 + b - d

I tried to do it using C_T_G(c,t) in the function DEFINE_PROFILE(name,t,i) to calculate grad(T) in the zones 1 and 2, but Fluent pointed out an error.