Internal/interior Boudaries with GAMBIT

pk

Hi,

I am trying to simulate a 3d flow around a 2 cylinders in a cross shaped.Both of them are in a Control Flow volume .

I have define with GAMBIT - the boundaries of my Control Flow volume as WALL (4 faces of a brick ) - One INLET VELOCITY (one face of my Control Flow volume) - one PREssure OUTLET (the last face of my control FLow volume).

My 2 cylinders are define as Internal Or Interior, but in both case I got this error msg , when I read the case in FLUENT:

"Cannot change interior.3 to interior because there is only one adjacent cell thread ".

What does it means ? Any clue ?

Thanks for any help