Biomathematics Seminar
Tuesday 3/20/07

Speaker: Laura Miller
Department of Mathematics
University of North Carolina - Chapel Hill

Title: Understanding tiny insect flight

Abstract:

In this presentation, I will discuss the the aerodynamic challenges of 
tiny insect flight and discuss possible morphological and kinematic 
adaptions to increase the lift forces generated. I explored flight 
aerodynamics over a range of Reynolds numbers using the immersed 
boundary method to numerically solve the two-dimensional Navier-Stokes 
equations with moving, flexible boundaries. For the smallest flying 
insects, my work has shown that flight becomes very inefficient as 
relative lift forces decrease and relative drag forces increase with 
decreasing Reynolds number. This effect is related to the behavior of 
the vortex wake behind the wing. At lower Reynolds numbers, neither 
leading nor trailing edge vorticity separates from the wings until 
stroke reversal. Tiny insects use the Weis-Fogh mechanism (clap and 
fling) to augment the lift forces generated during flight. My work has 
shown that there is, however, a large aerodynamic cost for this 
behavior. At lower Reynolds numbers, very large drag forces are 
required to perform the clap and fling. This negative effect can be 
reduced with wing flexibility and possibly wing bristles.