Numerical Analysis of Effects of Leading-Edge Protuberances on Aircraft Wing Performance

Abstract

This thesis investigates the effects of biologically inspired leading-edge protuberances on aircraft wings. The study of humpback whales and their flipper performance was the impetus to modifying the leading edge of an aircraft wing in order to gain an aerodynamic advantage during flight. This study examines the effect of leading-edge modification on wing performance at a low Reynolds number (Re), since low Reynolds number flows have unique features, and the knowledge about this flight regime is extremely important for small aircraft, called unmanned aerial vehicles (UAVs), flying at low speeds. Simulations were executed on wings with leading-edge sinusoidal protuberances, in order to compare the lift and drag characteristics with that of a wing with a smooth leading edge. All wings had the same cross section of National Advisory Committee for Aeronautics (NACA) 2412 and a simulated Reynolds number of 5.7 * 10^5. Results from numerical simulations revealed that a decrease in lift and an increase in drag was observed at low angles of attack (AoA) in all cases of the modified wings. At higher angles (α ≥16o), the lift of the modified wings was up to 48% greater than the baseline wing, with 44% less drag or no drag penalty. The amplitude of protuberances significantly affects wing performance. Although the maximum lift generated by modified wings was lower than baseline, protuberances along the leading edge of the wing proved to have a profound advantage in obtaining higher lift at high angles of attack.