Dynamic mesh
 

Hi everybody, I'm working about Synthetic jet (closed cavity with membrane on one side and an orifice face to the membrane). I identified the membrane as a piston and I identified the external domain as a pressure-outlet. The first mesh containe 19000 cells, all is ok for the first order equations.

- My problem is when I use the second order or equation or a mesh with more of cells (50000 cells or more) the jet flow will begin to oscillate from the 5th period of work until this oscillation enter into the cavity !! (the literatures say that it will be stable ).

- I tried to make a large cells arround the external domain to diminishe th effect of the reflection but I had no good results.

- Please, if you have any idea to solve this problem, you can contact me on : batikhahmad@hotmail.com ,