2007/05/10 by Anders Hedenström, Lars Johansson, Marta Wolf +3 · 4 citations
Engineering · #Biomimetic flight and propulsion mechanisms #Aerospace Engineering and Energy Systems #Fluid Dynamics and Turbulent Flows
paper · doi:10.1126/science.1142281
openalex publication_date 2007/05/10 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/23
The flapping flight of animals generates an aerodynamic footprint as a time-varying vortex wake in which the rate of momentum change represents the aerodynamic force. We showed that the wakes of a small bat species differ from those of birds in some important respects. In our bats, each wing generated its own vortex loop. Also, at moderate and high flight speeds, the circulation on the outer (hand) wing and the arm wing differed in sign during the upstroke, resulting in negative lift on the hand wing and positive lift on the arm wing. Our interpretations of the unsteady aerodynamic performance and function of membranous-winged, flapping flight should change modeling strategies for the study of equivalent natural and engineered flying devices.