[Kossivi]

Hi,

I'm working on a piston cylinder simulation and have some difficulty interpreting the solution I got from the rhoPimpleDyMFaom solver.

I have a of of 2 m diameter and 5 m long. the left end on the cylinder is supposed to the the piston moving and the right one is a fixed wall. So the fluid (air) is confined in the cylinder. According to what I understood from thermodynamics, the pressure must be uniform constant at each compression...and so for the Temperature and the density.
But in my simulation I observed some instability at the on two cells which are at the same pressure with the rest of the domain at the end of compression.
the moving piston is moving at the velocity of 1m/s.
So I need your help to figure out what me be I doing wrong in the process . I attached the case file .