I am trying to solve a transport equation in ansys fluent16 (The image of the equation has been attached) .I have 5 zones, 1 is fluid and the rest are porous media. The equation has to be solved in all zones. My problem is that the convective term is not the same as that in fluent uds transport equation. I have been told to use uds_flux function to change flux function. In order to do that i need boundary faces ids which are accessible from boundary condition task page. My question is that is it possible to access interior faces ids? because i need to set convective fluxes on those faces too. An early reply would be highly appreciated.