Flow control effectiveness of synthetic jet on a stalled airfoil

Abstract

Synthetic jet has attracted much attention for its use as an effective active flow control technique. With the aim of achieving a deeper understanding of the mechanisms and the critical fluid flow phenomena associated with synthetic jet, 2D simulations are conducted, in which a synthetic jet is placed on a NACA 0012 airfoil’s upper surface near the leading edge simulating the periodic blowing and suction control at Re = 5 × 10 5 and an angle of attack of 18°. Important control parameters, such as jet amplitude and frequency are investigated over a wide range and the jet width is also considered. Numerical results show that the recirculation region on the airfoil is decreased with a maximum increase in the lift by about 40 per cent and a reduced drag. The synthetic jet is found to be particularly effective at high forcing levels when the forcing frequency f e is close to the natural shedding frequency of the airfoil, and however become ineffective at low forcing levels. Use of higher forcing frequencies further decreases the drag of the airfoil but also reduces the lift.