title: Wake analysis of aerodynamic components for the glide envelope of a jackdaw (Corvus monedula).
abstract: Gliding flight is a relatively inexpensive mode of flight used by many larger bird species, where potential energy is used to cover the cost of aerodynamic drag. Birds have great flexibility in their flight configuration, allowing them to control their flight speed and glide angle. However, relatively little is known about how this flexibility affects aerodynamic drag. We measured the wake of a jackdaw (Corvus monedula) gliding in a wind tunnel, and computed the components of aerodynamic drag from the wake. We found that induced drag was mainly affected by wingspan, but also that the use of the tail has a negative influence on span efficiency. Contrary to previous work, we found no support for the separated primaries being used in controlling the induced drag. Profile drag was of similar magnitude to that reported in other studies, and our results suggest that profile drag is affected by variation in wing shape. For a folded tail, the body drag coefficient had a value of 0.2, rising to above 0.4 with the tail fully spread, which we conclude is due to tail profile drag.
authors.affiliation: Department of Biology, Lund University, Lund SE-223 62, Sweden Marco.Klein_Heerenbrink@biol.lu.se Anders.Hedenstrom@biol.lu.se.
authors.forename: Marco
authors.identifier: 0000-0001-8172-8121
authors.initials: M
authors.lastname: KleinHeerenbrink
authors.affiliation: Department of Biology, Lund University, Lund SE-223 62, Sweden.
authors.forename: Kajsa
authors.identifier: 0000-0003-1038-8953
authors.initials: K
authors.lastname: Warfvinge
authors.affiliation: Department of Biology, Lund University, Lund SE-223 62, Sweden Marco.Klein_Heerenbrink@biol.lu.se Anders.Hedenstrom@biol.lu.se.
authors.forename: Anders
authors.identifier: 0000-0002-1757-0945
authors.initials: A
authors.lastname: Hedenström
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D046368:Crows / Q000502:physiology*; D005426:Flight, Animal / Q000502:physiology*; D011187:Posture / Q000502:physiology; D013623:Tail; D014921:Wings, Animal / Q000502:physiology*
keywords: Aerodynamics; Biomechanics; Gliding flight; PIV; Particle image velocimetry; Wind tunnel; Wing morphology