Oscillatory cylinder
 

Hi
I try to simulate this paper:

A. Rehman, K. Kontis, Synthetic Jet Control Effectiveness on Stationary and Pitching Airfoil. Journal of Aircraft, 2006

in this paper, Dt is 0.0001.
When I use this time step flow field is wrong but when I use 0.001 flow field is correct.
I don't Know why?
Could you help me?:confused:

I attached these images.
1- steady state before unsteady calculation.
2- unsteady calculation with Dt=0.0001
3- unsteady calculation with Dt=0.001

Excuse me title is oscillatory airfoil, no oscillatory cylinder