Aerodynamic performance in bat flight

Abstract: Bats are the only mammals capable of flight, and they are the only animal flyers that are mammals. This thesis focuses on the latter of those facts, and investigates how bats fly, from an aerodynamic perspective. The data on which this thesis is based were generated by examining the airflows beneath and behind bats flying in a wind tunnel, and by examining their wing kinematics manually and automatically, using high-speed cameras. We analysed the data by writing computer scripts and interfaces that calculated forces, powers, efficiencies, and kinematical and morphological parameters. Among other things, we found hovering bats to have asymmetrical wingbeats with regard to up- and downstroke, discovered new levels of complexity in the wakes of large-eared bats, quantified the aerodynamic consequences of large ears in bat flight, and we devised a new method for automatically reconstructing the wing shapes of flying animals.