Mass Increase for closed system with moving wall
 

My issue is with a closed system filled with an ideal gas. It is a 2D axisymmetric model which also includes a moving wall representing a pressure wave generator or piston-cylinder assembly. The problem is the system's mass is steadily increasing. I have tried several variations on modeling the moving wall using various smoothing techniques. I am certain the moving mesh and its UDF is working properly with visual reference, however I believe the code is somehow adding mass on the back stroke.

Any help would be greatly appreciated. Thanks.

Coupled Flow _ Rigid Body Motion - Battery Cooling
 

Hello,
I have the same problem.
My mass flow rate is alternating increasing up to 700%.
The Residuals seems to be ok, but Tke and Tdr pass up quick above 1.

I am getting no pressure and temperature rise for rapid compression in fluid 2D axi-symetric acse

I have entered these values at initialisation

Problem is that I am not geting temp and pressure rise during compression stroke