Aeromechanics of Hovering Flight in Perturbed Flows: Insights from Computational Models and Animal Experiments

Abstract

Stability of flapping flight, a natural requirement for flying insects, is one of the major challenges for designing micro aerial vehicles (MAVs). To better understand how a flying insect could stabilize itself during hover, we have employed a fully coupled computational model, which combines the Navier-Strokes equations and the equations of motion in six degrees-of-freedom (NS6DOF) to model the hovering flight of a hawkmoth. These simulations are combined with high-speed videogrammetry experiments on live, untethered hawkmoths flying in quiescent and perturbed flows. The flight videos were used to identify a potential mechanism that could be used by the moth to stabilize its hovering flight; the effectiveness of this mechanism was investigated using CFD-based simulations and semianalytic approximations.= angular momentum of two wings in pitch

Hawkmoths use wingstroke-to-wingstroke frequency modulation for aerial recovery to vortex ring perturbations

“…One of the major challenges in measuring wingbeat frequency modulation is in designing experiments to elicit behaviors that deviate from steady-state [33]. We were inspired by prior studies that used mechanical perturbations to trigger recovery maneuvers in free flying insects [34,35]. In particular, prior work has shown that moths hover feeding from flowers can be successfully perturbed by vortex rings [35].…”

“…We were inspired by prior studies that used mechanical perturbations to trigger recovery maneuvers in free flying insects [34,35]. In particular, prior work has shown that moths hover feeding from flowers can be successfully perturbed by vortex rings [35]. We adopted a similar experimental paradigm and tuned the strength of the vortex perturbation to be just weak enough for the moth to remain airborne.…”