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A turbulent spot in a two-dimensional duct

Published online by Cambridge University Press:  21 April 2006

M. Sokolov ,
R. A. Antonia  and
A. J. Chambers
M. Sokolov
Affiliation:
Department of Fluid Mechanics & Heat Transfer, Tel Aviv University, Tel Aviv, 69978, Israel
R. A. Antonia
Affiliation:
Department of Mechanical Engineering, University of Newcastle, NSW, 2308, Australia
A. J. Chambers
Affiliation:
Department of Fluid Mechanics & Heat Transfer, Tel Aviv University, Tel Aviv, 69978, Israel
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Abstract

A turbulent spot is induced by a spark triggered in one of the laminar boundary layers in the entrance region of a two-dimensional duct flow. The development of the spot is studied using ensemble-averaged velocity and wall shear stress in the plane of symmetry of the spot. Following an initial growth of the spot, the potential-flow field associated with this spot triggers a second spot on the opposite wall of the duct. This new spot propagates at the same convection velocity as the original spot and grows until the turbulent regions occupied by the two spots completely fill the width of the duct. This transition mechanism differs significantly from that observed for a plane Poiseuille flow, where the spot fills the duct almost immediately after it is generated.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 166 , May 1986 , pp. 211 - 225
Copyright
© 1986 Cambridge University Press

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