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Accession Number ADA562723
Title Unsteady Flow Structure on Low Aspect Ratio Wings.
Publication Date Jan 2011
Media Count 106p
Personal Author D. Rockwell
Abstract The overall objective of this investigation was to determine the quantitative flow structure on low aspect ratio wings subjected to basic classes of maneuvers, in order to provide a basis for interpretation of induced forces. Techniques of particle image velocimetry were employed for critical planes of the flow field, and a technique of stereo particle image velocimetry was developed for water-based systems. Post-processing of the acquired images allowed determination of the vorticity and streamline topology, and construction of space-time volumes of the flow structure. These approaches led to characterization of the three-dimensional flow structure on flapping wings, as well as wings in rectilinear motion, and determination of patterns of spanwise- and streamwise-oriented vorticity. Passive control in the form of a sinusoidal leading-edge, which mimics the protuberances on the flipper of the humpback whale, and active open-loop control, in the form of small-amplitude perturbations of a wing can effectively can effectively manipulate the structure of the classes of flows investigated herein.
Keywords Aerodynamics
Aspect ratio
Flow fields
Flow separation
Particle image velocimetry
Passive systems
Three dimensional flow
Unsteady flow
Vortices
Wings


 
Source Agency Non Paid ADAS
NTIS Subject Category 51C - Aircraft
46B - Fluid Mechanics
Corporate Author Lehigh Univ., Bethlehem, PA. Dept. of Mechanical Engineering and Mechanics.
Document Type Technical report
Title Note Final rept. 1 FEb 2008-30 Nov 2010.
NTIS Issue Number 1225
Contract Number FA9550-08-1-0022-00002

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