Meeting Abstract

10.1  Tuesday, Jan. 4  Time-resolved measurements of the velocity field over the wing of a bat during flight SCHUNK, C.*; CHIU, C.; BAHLMAN, J.W.; BERGOU, A.; CHENEY, J.; WALDMAN, R.M.; CURET, O.; ALBRIGHT, E.; SWARTZ, S.M.; BREUER, K.S.; Brown University, Providence, RI; University of Maryland, College Park, MD; Brown University, Providencem, RI; Brown University, Providence, RI; Brown University, Providence, RI; Brown University, Providence, RI; Brown University, Providence, RI; Brown University, Providence, RI; Brown University, Providence, RI; Brown University, Providence, RI cosima_schunk@brown.edu

Particle Image Velocimetry (PIV) has become a well-established tool to study flows associated with flying animals, including bats, and such measurements can provide valuable insight about an animal’s flight performance and how wing motion affects changes in lift generation that occur over the wingbeat cycle. Most previous studies have been performed by placing the laser light sheet downstream of the animal, thus capturing the wake flow. Here, we present time-resolved, on-wing measurements of the three-dimensional velocity field generated by a bat during flight. One individual big brown bat, Eptesicus fuscus, was trained to fly at a stationary position within the test section of a wind tunnel at a speed range of 4.5 m/s to 7 m/s. We measured the air flow around the left wing of a flying bat and in the wake immediately behind it using time-resolved (200 Hz) stereo PIV. In addition, three high-speed cameras (400 Hz) were used to capture the position and movement of the bat and to reconstruct the wing kinematics. The details of the wing flows, the tip and secondary vortex formation are all captured over multiple wingbeats.