Aerodynamic Characteristics of Finite Span Wings with Leading Edge Protuberances

A series of water-tunnel experiments were conducted to determine the effect of sinusoidal leading-edge protuberances on the aerodynamic characteristics of finite span wings. The models consisted of seven rectangular planform wings, two swept-leading-edge wings, and two wings with a planform resembling humpback-whale flippers. All models had an underlying NACA 634-021 profile with protuberance amplitudes of 0.025–0.12 times the chord length. The models were examined at Reynolds numbers up to 4.5×105 and angles of attack up to 30 deg. The lift and drag coefficients were nearly independent of Reynolds numbers above 3.6×105. Specific rectangular-planform models had appreciably greater lift coefficients over a limited angle-of-attack range when compared to the baseline model. However, with the exception of the planform that resembled the humpback-whale flipper, the lift-to-drag ratio of all leading-edge modified models was comparable to or less than the equivalent baseline model. The flipper model had a slight...