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Transport in the near aerodynamic wakes of flat plates

Published online by Cambridge University Press:  20 April 2006

A. S. M. Maclennan  and
J. H. Vincent
A. S. M. Maclennan
Affiliation:
Department of Applied Physics, University of Strathclyde, Glasgow, Scotland Present address: Sperry Gyroscope, Bracknell, Berks, England.
J. H. Vincent
Affiliation:
Physics Branch, Institute of Occupational Medicine, Edinburgh, Scotland
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Abstract

An experimental investigation has been carried out into the nature of the transport of airborne material in the near aerodynamic wakes of bluff bodies with simple shapes. The main attention was focused on the essential differences existing between axi- symmetric flows (as about disks) and two-dimensional flows (as about rectangular long thin flat plates). Measurements were made for such bodies of the near-wake residence time of injected small particles, along with other and more familiar near- wake properties such as the vortex-shedding frequency and base pressure. It was concluded for disks that the transport of material into and out of the near-wake region is dominated by turbulent diffusion, and is strongly influenced by free-stream turbulence, especially for free-stream turbulence whose length scale is substantially smaller than the disk diameter. For rectangular flat plates, transport is dominated by the periodic shedding of vortices, and to only a secondary extent by turbulent motions, and is not strongly influenced by free-stream turbulence.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 120 , July 1982 , pp. 185 - 197
Copyright
© 1982 Cambridge University Press

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