Control of self-induced roll oscillations using the sinusoidal leading-edge for low-aspect-ratio wings

A study on attenuating the self-induced roll oscillations of low-aspect-ratio flat-plate wings was conducted experimentally in a wind tunnel facility using a bionic flow control approach of the sinusoidal leading-edge (SLE). It was found that the effectiveness of the SLE on roll attenuation strongly depends on its amplitude and wavelength. Velocity measurements indicated that the SLE can generate streamwise counter-rotating vortex pairs (CVPs). These CVPs induce downwash flow, resulting in a decline in height of the leading-edge separated flow, thus attenuating roll oscillations. Force measurement results suggest that by choosing the appropriate wavelength-to-amplitude ratio of the SLE, self-induced roll oscillations can be suppressed with improved lift characteristics of the wing. Graphic abstract