Open-Loop Flow Control At Low Reynolds Numbers Using Periodic Airfoil Morphing

© 2015 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. This paper investigates the application of a periodically deforming airfoil surface for the purpose of flow control at low Reynolds numbers. A physical model has been fabricated by bonding Macro Fiber Composite actuators to the underside of an airfoil’s suction surface. This model is actuated using a high voltage amplifier and has been tested in a closed-loop wind tunnel at Rec = 5 × 10 4 . It was found that at high enough actuation frequencies such a control technique reduces drag and simultaneously increases lift { thus achieving signif- icant improvements in performance in a flight regime notorious for poor airfoil behavior. Furthermore, by delaying the onset of stall, actuation was able to increase the maximum lift achievable by this airfoil section at Rec = 5 × 10 4 which can be of benefit to small aircraft at take-off and landing where high lift coeffcients are required.