Unsteady Aerodynamics of Insect Flight

Jane Wang

The myth `bumble-bees can not fly according to conventional

aerodynamics' simply reflects our poor understanding of

unsteady viscous fluid dynamics. In particular, we lack a

theory of vorticity shedding due to dynamic boundaries at

the intermediate Reynolds numbers relevant to insect flight,

typically between 10^2 and 10^4, where both

viscous and inertial effects are important. In our study,

we compute unsteady viscous flows, governed by the Navier-Stokes

equation, about a two dimensional flapping wing which

mimics the motion of an insect wing. I will present two main

results: the existence of a preferred frequency in forward flight

and its physical origin, and 2) the vortex dynamics and forces

in hovering dragonfly flight. If time permits, I will show

the recent results on comparing our computational results

against robotic fruitfly experiments and modeling three

dimensional flapping flight driven by muscles.