68th Annual Meeting of the APS Division of Fluid Dynamics (November 22, 2015 — November 24, 2015)

V0088: Turning on a Dime – Asymmetric Vortex Formation in Hummingbird Maneuvering Flight

Authors

• Yan Ren, University of Virginia
• Haibo Dong, University of Virginia
• Xinyan Deng, Purdue University
• Bret Tobalske, University of Montana

DOI: https://doi.org/10.1103/APS.DFD.2015.GFM.V0088

Hummingbirds are versatile natural flyers that can perform locomotion as insects, such as hovering, forward/backward flight, turning maneuver and more. The unsteady vortex dynamics is key to understand aerodynamic features of these motions. Here we present an integrated approach combining high-speed photogrammetry, wing/body surface tracking, and immersed boundary method based flow simulations to study the three-dimensional vortex dynamics of a freely maneuvering hummingbird. The simulation results of the hummingbird performing pure yaw turn show asymmetric wake structures between the inner and outer wings. Dual-loop vortex structures have been observed in the near wake of the outer wing during downstroke, and of the inner wing during upstroke. The interactions between the wings and these complex vortex structures have implied both aerodynamic and dynamic benefits of the flapping wings in hummingbird’s maneuvering flight. (This work is supported by NSF CBET-1313217 and AFOSR FA9550-12-1-0071)