An experimental investigation on the aerodynamics of the Pseudaletia Unipuncta moth subjected to varying upstream flow conditions
Résumé
The effects of varying flow conditions on the flight and wake of the Pseudaletia Unipuncta moth were investigated, for the first time, using Particle Image Velocimetry (PIV) measurements on a live tethered moth, subjected to three upstream flow conditions: no flow (hover), smooth flow and perturbed flow. High-Speed Imaging (HSI) was used to study the basic kinematics of the moth, from which the wingbeat frequency (F) of the moth was found to be approximately 45 Hz. In configurations with no upstream flow, a possible Leading Edge Vortex (LEV) was observed as well as counter-rotating vortices in the moth's wake. Varying the upstream flow conditions significantly changed the mean turbulent statistics in the moth's wake, with larger levels of mean turbulent kinetic energy being observed in configurations with upstream flow compared to configurations with no upstream flow. It was observed that the mean flow perturbation modified the wake generated by the moth.