Decaying of Flow Separation from a Low Reynolds Number Airfoil with High Frequency Perturbations

Abstract

Piezo-ceramic actuators were used to decay boundary layer separation from a NACA0015 airfoil. The actuators generated a small normal-to-surface perturbation near the leading edge of the airfoil. While the flow field around the airfoil was measured using a particle imaged velocimeter, instantaneous lift and drag forces were obtained using a load cell. The results show that the flow separation can be postponed by this perturbation as long as the perturbation frequency is high enough, say higher than 10 times of the dominant frequency of vortex shedding from the airfoil. It was found that the static-stall angle of attack can be extended by 1 degrees similar to 2 degrees at the present Reynolds number of 1.2x10(5).