Unsteady load alleviation on highly flexible bio-inspired wings in longitudinally oscillating freestreams

TL;DR

This paper investigates how highly flexible bio-inspired wings can reduce unsteady aerodynamic loads in gusty conditions, combining experimental, numerical, and theoretical insights to suggest potential for energy-efficient flight.

Contribution

It introduces a numerical study on flexible wings inspired by avian feathers, demonstrating their ability to mitigate oscillating aerodynamic forces through flow stabilization mechanisms.

Findings

Flexible wings destabilize laminar separation bubbles

Flow stabilization leads to more turbulent boundary layers

Potential for energy-efficient flight in gusty environments

Abstract

This study delves into the aerodynamic behavior of a highly flexible NACA 0012 aerofoil, drawing inspiration from avian feathers to handle a gust. We first examined unsteady flow on a rigid wing both experimentally and numerically and then explored the implications of introducing wing flexibility purely numerically. Our findings underscore the potential of composite materials in alleviating the oscillating aerodynamic forces on a wing under a streamwise gust. This behavior is attributed to its capacity to destabilize the laminar separation bubble, fostering a more stable turbulent boundary layer. While direct avian evidence remains limited, it is postulated that in nature, such mechanisms could mitigate undesired wing flapping, optimizing energy consumption in perturbed environments.