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Vortex formation and drag on low aspect ratio, normal flat plates

Citation

Ringuette, Matthew James (2004) Vortex formation and drag on low aspect ratio, normal flat plates. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-05292004-183807

Abstract

Experiments were done to investigate the role of vortex formation in the drag force generation of low aspect ratio, normal flat plates starting from rest. This very simplified case is a first, fundamental step toward understanding the more complicated flow of hovering flight, which relies primarily on drag for propulsion. The relative importance of the plate's free end, or tip, with varying aspect ratio was also studied.

Identifying the relationship among aspect ratio, vortex formation, and drag force can provide insight into the wing aspect ratios and kinematics found nature, with the eventual goal of designing man-made flapping wing micro air vehicles.

The experiments were carried out using flat plate models in a towing tank at a moderate Reynolds number of 3000. Two aspect ratios, 6 and 2, were considered, the latter in order to have a highly tip-dominated case. A force balance measured the time-varying drag, and multiple, perpendicular sections of the flow velocity were measured quantitatively using digital particle image velocimetry. Vorticity fields were calculated from the velocity data, and features in the drag force for different aspect ratios were related to the vortex dynamics. Finally, since the flow is highly three-dimensional, dye flow visualization was done to characterize its structure and to augment the two-dimensional digital particle image velocimetry data.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:aspect ratio; drag; flat plate; vortex formation
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Gharib, Morteza
Thesis Committee:
  • Gharib, Morteza (chair)
  • Leonard, Anthony
  • Burdick, Joel Wakeman
  • Dickinson, Michael H.
Defense Date:21 May 2004
Record Number:CaltechETD:etd-05292004-183807
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-05292004-183807
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2241
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:01 Jun 2004
Last Modified:26 Dec 2012 02:48

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