Abaqus CFD

Hello,

I have a 6mm straight tube which is pressureized to 8bar dry air, then the pressure is 

released to 2 bar and the time is measured. (pressure drop duration)

I wonder if this problem is possible to analyize in Abaqus CFD?

In abaqus CFD i can assign 8 bar pressure at one end of the tube and 2 bar at

the other end but then i wonder if Abaqus will adjust the velocity to achieve this 

solution during the specified step time, if this is the case then i will not

be able to get the correct time?

Can you please advise!! also if there is a way yo calculate the time by hand?

Best regards

Ali