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A class of elliptical free-surface flows

Published online by Cambridge University Press:  20 April 2006

A. L. New
Affiliation:
School of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, England Present address: Institute of Oceanographic Sciences, Crossway, Taunton, Somerset TA1 2DW.

Abstract

Exact solutions of the equations of motion for an inviscid fluid are rare. Using the formalism of John (1953), this paper presents a class of exact zero-gravity flows in which the free surface assumes the form of an ellipse having arbitrary but time-constant aspect ratio. The dynamically important region beneath the overturning crest of a breaking gravity wave is examined and the profile is found to be remarkably well approximated by a √3 aspect-ratio ellipse. The range of examples presented includes high-resolution computations in both deep and shallow water, and also the plunger-generated laboratory waves of Miller (1976).

The ellipse solution is shown to model qualitatively certain essential features of the numerical waves. A recent self-similar solution due to Longuet-Higgins (1981, 1982), in which the free surface is a parametric cubic curve, is also discussed.

Type
Research Article
Copyright
© 1983 Cambridge University Press

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