[reggid]

Hi i am trying to look at the flow behavior from atmospheric conditions into a finite container caused by the motion of the piston moving at a velocity V.

i cant seem to work out the proper boundary conditions for the inlet and outlet for a non transient analysis.

i can do a pressure differential but don't believe this is the best approach.

if i'm not mistaken the air immediate to the top of the piston should always move vertically and at the same speed as the piston itself? how do you input that as a boundary condition?

also can anyone point me in the direction of a tutorial to simulated this in a transient analysis with a moving boundary?

here is a sketch