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Coastal upwelling on a sloping bottom: the formation of plumes, jets and pinched-off cyclones

Published online by Cambridge University Press:  21 April 2006

S. Narimousa  and
T. Maxworthy
S. Narimousa
Affiliation:
Department of Mechanical Engineering, University of Southern California, Los Angeles, CA 90089–1453, USA
T. Maxworthy
Affiliation:
Department of Mechanical Engineering, University of Southern California, Los Angeles, CA 90089–1453, USA
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Abstract

An experimental, two-layer, stratified model of coastal upwelling was produced at the outer edge of a cylindrical tank having a conical bottom. As in Narimousa & Maxworthy (1985), we find that most of the characteristics of the flow field can be described by the single non-dimensional parameter θ* = g′h0/μ*fλs (where g′ = gδP is the reduced gravity, h0 is the initial depth of the top layer, μ* is the friction velocity applied to the top surface of the fluid, f is the Coriolis parameter and λs is the distance of the stationary position of the upwelling front at the surface from the wall of the tank). For example, we find that the migration rate of the front at the surface, μf is given by μf/μ* ∼ θ−½*; the size λW of the frontal, circular waves is λW/λs ∼ θ*; that these waves first appear at the front when it has moved a distance λi < λs given by λi/λs ∼ θ−½*; and have a final drift velocity μw ≈ 0.5 U in the direction of the applied stress (where U is the mean velocity of the top layer). At low values of θ* complex interactions between the growing waves created intense meandering jets which transported upwelled fluid far from the mean position of the front.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 176 , March 1987 , pp. 169 - 190
Copyright
© 1987 Cambridge University Press

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