Meeting Abstract
Bumblebees are relentless foragers capable of flying in a wide range of weather conditions. Flight in unsteady wind is of particular interest as it presents a complex dynamical interaction between the fluid and the insect. To interpret the observed behavior and identify the control strategies employed, it is essential to disentangle the voluntary maneuvering performed by the insect from the passive mechanical response of the flight apparatus in unsteady winds. Here we analyze the lateral flight dynamics of bumblebees through a combination of experimental observations and high fidelity numerical simulations. Detailed flight trajectories of bumblebees flying upwind in unsteady winds towards an artificial flower were measured using high speed videography. Unsteady wind was generated by placing a vertical cylinder at the inlet of the wind tunnel test section, resulting in the formation of a von Kármán vortex street in the wake. We also performed high fidelity numerical simulations of a bumblebee with similar anatomical features, flying in similar unsteady wind, with no flight control to investigate the passive dynamic interactions. By comparing the experiment and the numerical simulation, we reveal that the flight path of the bee is a result of the superposition of two distinct modes: a voluntary low-frequency casting motion and a passive high-frequency buffeting. Our findings suggest that bumblebees use a combination of active and passive strategies to mitigate the challenges imposed by wind unsteadiness.
