Aerodynamic response of flapping wings to brief gust perturbations

Natural fliers frequently encounter various perturbed flows during their daily flapping flights. To address the flight stability issue of the flapping micro aerial vehicles under additional aerodynamic loads induced by gust disturbances, inspired by natural flyers, this study numerically solves the unsteady Navier–Stokes equations to investigate the influence of brief gusts on the aerodynamic characteristics of rigid flapping wings. A comprehensive analysis is performed on the effects of gust amplitude, frequency, phase, and waveform on the aerodynamic forces and vortex shedding of the flapping wing. The results show that the lift response is stronger than the thrust response, and the variance of the net aerodynamic force increment is concentrated in the region where the gust amplitude is 1–1.5 times the maximum flapping speed and the gust duration is 0.5–1 times the flapping period. A phase difference between the gust input and the flapping stroke leads to a substantial increase in aerodynamic loads. The overall aerodynamic response of the flapping wing varies only slightly across different gust waveforms. The flapping wing performs better in resisting square-wave gusts but has greater difficulty maintaining balance under sawtooth-wave gusts. The present findings are valuable for developing robust flight control strategies and providing design guidance for micro aerial vehicles.