University of Illinois Urbana-Champaign

Bio-inspired adaptive wingtip devices for low Reynolds number operation

Lynch, Michael K

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LYNCH-THESIS-2017.pdf

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https://hdl.handle.net/2142/97802

Description

Title
Bio-inspired adaptive wingtip devices for low Reynolds number operation
Author(s)
Lynch, Michael K
Issue Date
2017-04-28
Director of Research (if dissertation) or Advisor (if thesis)
Wissa, Aimy
Department of Study
Mechanical Sci & Engineering
Discipline
Mechanical Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Date of Ingest
2017-08-10T20:33:31Z
Keyword(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.
Graduation Semester
2017-05
Type of Resource
text
Permalink
http://hdl.handle.net/2142/97802
Copyright and License Information
Copyright 2017 Michael K. Lynch

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