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

That's because they're not interior BC's. An interior BC allows fluid to pass through it without any interference (these are good for post-processing, or if you want to switch this surface to another BC later on, like a Pressure-Jump or a Wall, but that's it).

What you're trying to do is specify the cylinders as Walls. This way the flow can't pass through the BC and will be diverted around it.

Another way of looking at it...

An Interior BC is an imaginary plane you can use to look at or calculate flow properties, while a Wall BC is the equivalent to a hard surface which doesn't allow flow to pass through it.

Good luck, Jason