Meeting Abstract

70.5  Tuesday, Jan. 6  Individual variability in the aerodynamics and kinematics of bat flight HUBEL, Tatjana*; BREUER, Kenneth; SWARTZ, Sharon; Brown University tatjana_hubel@brown.edu

Many studies on the aerodynamics of flight in birds and bats use relatively few individuals. However, previous work in our lab has shown that the kinematics of flight can vary significantly from individual to individual within a species. In this study, we sought to determine the degree to which differences in kinematics were reflected by the wake patterns generated during flight. We made measurements of bat flight in a wind tunnel using four high-speed cameras (200 Hz) and time-resolved PIV (200 Hz) perpendicular to the flow stream, behind the bat. Five Lesser dog-faced fruit bats ( Cynopterus brachyotis ) were trained to fly in the wind tunnel at speeds of three to seven ms-1. Several landmarks on the body, wing bones, and wing membrane were marked to allow high fidelity 3D reconstruction of wing kinematics. Each PIV acquisition sequence was correlated to the kinematics, accounting for the varying distance between the PIV laser light sheet and the bat wing, and correcting for the acceleration of the bat with respect to the wind tunnel. Our PIV recordings show the development of the tip vortex and circulation over the course of each wing beat cycle. The variability in position of the bat (maneuvering), and in the kinematics of the bat from wingbeat cycle to wingbeat cycle were substantial and this is reflected in the resulting wake signature measured using PIV.