Adaptive Feedback Control of Flow Separation

Abstract

An adaptive feedback disturbance rejection algorithm is applied in conjunction with a piezoelectric synthetic jet actuator and surface mounted unsteady pressure transducers to control the separated flow on a NACA 0025 airfoil model at and . The goal of this feedback control scheme is to suppress the pressure fluctuations on the upper surface of the airfoil model, which results in reduced flow separation, increased lift, and reduced drag. A recursive ARMARKOV system identification (ID) algorithm is used to estimate the flow dynamics and does a good job of tracking the unsteady pressure sensor output. The disturbance rejection algorithm is able to reduce the broadband power of the pressure fluctuations by up to ~5 dB. Furthermore, the flow is completely reattached and the lift/drag ratio, measured using an integrated balance, is increased by a factor of ~5 using 1/3 12 α = 5 Re 10 c =