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The growth and breakdown of streamwise vortices in the presence of a wallThe growth and breakdown of counter-rotating streamwise vortices, generated on a concave wall via the Goertler instability mechanism, were experimentally studied as a model for comparable eddy structures that exist in transitional and turbulent flat-plate boundary layers. The experiments were conducted in a low-speed open-return wind tunnel, using smoke-wire visualization and multiple-probe hot wires to study the vortices. As low-momentum fluid was removed from the wall, low-speed regions formed between the vortices; these regions grew in the normal direction faster than a nominally Blasius boundary layer and created strongly inflexional normal and spanwise profiles of the streamwise velocity component. Instability oscillations developed on these unstable profiles that scaled with the local shear-layer thickness and velocity difference. The spatial scales of the temporal velocity fluctuations were found to correlate with the velocity gradient in the spanwise (rather than in the normal) direction.
Document ID
19880027233
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Swearingen, Jerry D.
(University of Southern California Los Angeles, CA, United States)
Blackwelder, Ron F.
(Southern California, University Los Angeles, CA, United States)
Date Acquired
August 13, 2013
Publication Date
September 1, 1987
Publication Information
Publication: Journal of Fluid Mechanics
Volume: 182
ISSN: 0022-1120
Subject Category
Fluid Mechanics And Heat Transfer
Accession Number
88A14460
Funding Number(s)
CONTRACT_GRANT: F49620-78-C-0060
CONTRACT_GRANT: NAG1-19
Distribution Limits
Public
Copyright
Other

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