Divergence in Dynamic Mesh Problem

James

Hello all. I have been trying to model a 2-d engine cycle using my own geometry. My problem set-up is very similar to the fluent tutorial. The movement and mesh handling appear to be set up correctly but when I try to solve the problem, the solution diverges when the valves just open. i.e. at very low valve lifts. I have set the min absolute pressure at 1000 PA and the max at 5000000 Pa. also the min static temp is 100K. I have also used the same under-relaxation factors that are in the tutorial.

Can anyone who has experience of this type of simulation advise me on how to avoid this problem at low valve lifts?

I would be very grateful for any assistance. Sorry for the long post!!

James. (james.oloughlin@ul.ie)