Effect of the wavy leading edge on hydrodynamic characteristics for flow around low aspect ratio wing

The present study numerically investigates the effect of the wavy leading edge on hydrodynamic characteristics for the flow of rectangular wings with the low aspect ratio of 1.5 at one Reynolds number of 106 based on free stream velocity and the chord length C. The waviness ratio Rw is defined by the span length of wing to the spanwise length covered by the waviness. Five different waviness ratios of 0.2, 0.4, 0.6, 0.8 and 1.0 at fixed wavelength of 0.2C and wavy amplitude of 0.025C have been considered. The smooth wing and Rw = 0.2 revealed the similar variation of lift coefficient CL according to the angle of attack α, resulting in the same stall angle of 20°, where the maximum lift appears. The case of Rw = 0.6 presented the earliest occurrence of the stall at α = 12°. The cases of Rw = 1.0, 0.8 and 0.4 produced the same stall angle of α = 16°. In the post-stall region, CL for Rw = 0.4, 0.6, 0.8 and 1.0 recovered and became larger than those of the smooth wing and Rw = 0.2. A spiral formation of the limiting streamlines occurred in the wavy troughs, which derive relatively low pressure along the leading edge.