Resonance of flexible flapping wings at low Reynolds number

TLDR

The study uses 3‑D simulations to examine the hovering aerodynamics of flexible planar wings oscillating at resonance. Flexible wings are modeled as tilted elastic plates whose sinusoidal plunging motion is imposed at the plate root. Simulations show that large‑amplitude resonance of elastic wings greatly increases lift and efficiency at low Reynolds numbers, producing hovering forces comparable to small insects and demonstrating feasibility for efficient microscale flyers.

Abstract

Using three-dimensional computer simulations, we examine hovering aerodynamics of flexible planar wings oscillating at resonance. We model flexible wings as tilted elastic plates whose sinusoidal plunging motion is imposed at the plate root. Our simulations reveal that large-amplitude resonance oscillations of elastic wings drastically enhance aerodynamic lift and efficiency of low-Reynolds-number plunging. Driven by a simple sinusoidal stroke, flexible wings at resonance generate a hovering force comparable to that of small insects that employ a very efficient but much more complicated stroke kinematics. Our results indicate the feasibility of using flexible wings driven by a simple harmonic stroke for designing efficient microscale flying machines.