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Laboratory observations of a gravity current on a sloping bottom: the generation of shelf waves

Published online by Cambridge University Press:  21 April 2006

John A. Whitehead  and
David C. Chapman
John A. Whitehead
Affiliation:
Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
David C. Chapman
Affiliation:
Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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Abstract

A source of light water was started along the outside vertical wall of a cylindrical tank in uniform rotation. Like wall gravity currents studied previously, it had a nose which detrained eddies as it propagated. The gravity current then impinged upon a sloping bottom with the following effects: (i) the gravity current became more laminar; the detrainment of eddies at the nose and off the side of the current ceased; (ii) the gravity current became wider; (iii) the gravity current suddenly slowed and then continued to decelerate; (iv) when the gravity current was slower than the first-mode barotropic shelf wave, a shelf wave was radiated ahead of the gravity current; and (v) the deceleration was significantly greater than the deceleration of a gravity current next to a vertical wall. This is probably attributable to shelf-wave radiation drag, viscous effects and a finite energy source, although the relative importance of each remains an open question.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 172 , November 1986 , pp. 373 - 399
Copyright
© 1991 Cambridge University Press

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