Research on the regulatory mechanisms of flexible wing twisting motion on aerodynamic performance and energy recovery

Flapping wing micro aerial vehicles (FWMAVs) with flexible wings offer unique advantages across multiple scenarios due to their high energy efficiency and precision capabilities. This study explores the fluid-structure interaction (FSI) mechanisms and aerodynamic performance differences among three flexible wing motion patterns – passive twisting (PT), chordwise active twisting (CAT), and ‘Figure-8’ active twisting (FAT) – using a bidirectional FSI numerical simulation platform. A bionic wing model (aspect ratio AR = 3.86) and a Multiphysics-coupled framework were developed to evaluate the effects of dynamic wing torsion on lift and energy recovery. Results show that PT enhances aerodynamic performance by delaying flow separation and stabilising leading-edge vortices (LEVs). At 4 m/s, the average lift of flexible wings (FW) with PT is 6.31 times higher than that of rigid wings (RW). Active twisting strategies further improve efficiency: CAT increases average lift by 143% compared to PT at θmax = 40°, while FAT achieves 14.9% energy recovery rate through wake capture and elastic potential energy release, with an elastic energy release rate 2.79 times higher than CAT. Vortex dynamics analysis reveals that active twisting optimises lift by enhancing LEV circulation and proximity to the wing surface. CAT strengthens LEV attachment near the wing root, while FAT stabilises vortices at the wingtip. This research provides insights into energy efficiency optimisation and active control strategies for FWMAVs, highlighting the benefits of flexible deformation and intelligent motion regulation in improving aerodynamic performance and energy management.