Numerical study on flow separation control of cascades with synthetic jet using dynamic mesh method

The flow control effect of synthetic jet was numerically investigated by solving the three-dimensional viscous unsteady Navier-Stokes equations based on large-eddy simulation (LES) and dynamic mesh method. The maximum velocity of synthetic jet is 6. 5m/s and the exciting frequency is 80Hz. The results indicate that, a shear layer is formed at the orifice outlet and the shear layer rolls up to form a vortex ring in the blowing process. Fluid around the orifice enters into the cavity, and the vortex pair moves away from the orifice under its own momentum when the membrane moves to the bottom position in the suction process. Sinusoidal distribution was appeared at the jet outlet. The LES results show that obvious flow control effect is obtained by the synthetic jet control device. In the time averaged results, the separation area reduces to 17.23%C_ax (chord length in axial direction) from 28. 60%C_ax by the jet. Effect of suppressing flow separation are existed in both blowing and suction process but the control effect during blowing-suction alternating process and suction process is weaker.