Unsteady aerodynamics and odorant transport in an upwind surging flight of drosophila

For foraging and mating purposes, insects rely on their olfactory system to detect odor stimuli and track down odor sources using their high-efficient flapping wing mechanism. However, we have little understanding of how insects utilize the local filament-like odor plume structures to perceive the surrounding dynamic environments. In this study, a fully coupled three-way numerical solver is developed, which solves the 3D Navier-Stokes equations coupled with equations of motion for the passive flapping wings and the odorant advection-diffusion equation. High-fidelity numerical simulations of a model fruit fly in surging upwind flight is performed, superimposing isotropic turbulent fluctuations to the uniform inflow. A parametric study is conducted to investigate unsteady aerodynamics and odorant transport over a range of key parameters, including turbulent intensity, reduced frequency, Reynolds number, and Schmidt number. Our simulation results will provide new insights into the mechanism of how fruit flies perceive odor landscape and inspire the future design of odor-guided micro aerial vehicles for surveillance and detection missions.