Coupled dynamics and scaling relations of thin flexible wings with multiple distributed feathers

This study investigates the coupled aeroelastic dynamics and performance enhancement of thin flexible wings equipped with multiple distributed feathers, motivated by bio-inspired design of agile micro-air and unmanned aerial vehicles. A multi-body aeroelastic framework is developed by coupling an incompressible Navier–Stokes solver with large-eddy simulation in an arbitrary Lagrangian–Eulerian frame and a flexible multi-body structural model. The aeroelastic solver is applied to examine the aerodynamic performance of thin flexible wings without feathers, with a single leading-edge feather and with multiple overlapping feathers over a range of angles of attack, feather preset angles and feather lengths at Re = 2500. The results show that multi-feather configurations reorganize leading-edge vortex dynamics, yielding higher lift and lift-to-drag ratios than membrane-only wings. This is particularly evident in pre-stall and transitional regimes, where the design also keeps drag penalties moderate and reduces force fluctuations. A shallow positive preset angle combined with an intermediate feather length establishes a soft chordwise slot that sustains a gently convecting leading-edge vortex, accelerates pressure recovery and improves aerodynamic efficiency. When feathers become too long or too steep, blockage effects re-inflate drag and degrade performance. A new empirical scaling relation incorporating bounded feather coverage and preset-angle modifiers is proposed to predict the maximum membrane deformation under a Weber-number backbone. These findings provide quantitative guidelines for designing feathered morphing membrane wings with tunable lift, efficiency and stability across a wide angle-of-attack envelope.