Bio-inspired adaptive wingtip devices for low Reynolds number operation

Lynch, Michael K

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

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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