hello plm community,

 what i am trying to do here is simulate an air flow that enters from one side of the cylinder and exits from those small holes at its bottom to the cube represents the environment that the air will flow in, i need to know how we apply BC AND IN WHICH FACES  , i am not experts so your help would be very much appreciated and any answer can help me a lot.

i need to know what bc i need to use to get a realistic results 

the part is down bellow

thank you in advance sir.