periodic boundary condition
 

hi every body
I'm simulating an enclosure with 2 inlet and 2 outlet, i have to simulate boundaries as 2 sets of periodic boundaries. when i set periodic boundary conditions and when i want to set ''periodic condition>> flow direction'' i encounter my problem, i dont know how to set flow direction, because fluent automatically change direction when i set it for one group of periodic conditions.
i will be grateful for any kind of suggestion