Unsteady low-Reynolds Number Flow Control in Different Regimes

Low-Reynolds number wings are susceptible to flow separation due to high viscous effects. Combined with wind gusts, the aerodynamic performance can highly fluctuate. In this study, we continue to investigate the open-loop and closed-loop control strategies aimed at mitigating lift fluctuations due to free-stream unsteadiness for a SD7003 airfoil at the chord Reynolds number of 1000. The flow control framework is based on the dielectric barrier discharge (DBD) actuator and a penalty-driven adaptive law incorporating generic system identification methods. The Strouhal number and reduced frequency of the freestream oscillation defines multiple disturbance regimes, where topological changes in liftdrag profile, stall vortex shedding, and multi-harmonic oscillations are characterized. The control system effectively reduces the lift fluctuations due to the disturbance-driven unsteady vortex dynamics, offering improved understanding of effective control mechanisms. © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.