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Title:Bio-inspired adaptive wingtip devices for low Reynolds number operation
Author(s):Lynch, Michael K
Advisor(s):Wissa, Aimy
Department / Program:Mechanical Sci & Engineering
Discipline:Mechanical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Avian-inspired flight
Wingtip devices
Multiple winglets
Low Reynolds
Abstract:Birds are highly capable and maneuverable fliers, traits not currently shared with current unmanned aerial vehicles. They are able to achieve these flight capabilities by adapting the shape of their wings during flight in a variety of complex manners. One feature of bird wings, the primary feathers, separate to form wingtip gaps at the distal end of the wing. This research presents bio-inspired wingtip devices with varying wingtip gap sizes, defined as the chordwise distance between wingtip devices, for operation in low Reynolds number conditions of Re = 100,000, similar to conditions experienced by many species of birds. Lift and drag data was measured for planar and nonplanar wingtip devices with the total wingtip gap size ranging from 0% to 40%. For a planar wing with a gap size of 20%, the mean coefficient of lift in the pre-stall region is increased by 7.25%, and the maximum coefficient of lift is increased by 5.6% compared to a configuration with no gaps. The nonplanar wingtip device was shown to reduce the induced drag. The effect of wingtip gap sizes is shown to be independent of the planarity/nonplanarity of the wingtip device, thereby allowing designers to decouple the wingtip parameters to tune the desired lift and drag produced. A light weight morphing mechanism design process is proposed, thereby enabling designers to build an adaptive wing that takes advantage of high lift benefits of having 20% wingtip gaps, useful for high payload conditions, as well as low drag benefits of having no gaps, useful for cruise conditions.
Issue Date:2017-04-28
Rights Information:Copyright 2017 Michael K. Lynch
Date Available in IDEALS:2017-08-10
Date Deposited:2017-05

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