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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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References

Crapper, G. D. 1957 An exact solution for progressive capillary waves of arbitrary amplitude J. Fluid Mech. 2, 532540.Google Scholar
Greenhow, M. 1983 Free-surface flows related to breaking waves (unpublished manuscript).
John, F. 1953 Two-dimensional potential flows with a free boundary Communs Pure Appl. Maths 6, 497503.Google Scholar
Lamb, H. 1932 Hydrodynamics, 6th edn. Cambridge University Press.
Longuet-Higgins, M. S. 1972 A class of exact, time-dependent, free-surface flows J. Fluid Mech. 55, 529543.Google Scholar
Longuet-Higgins, M. S. 1976 Self-similar, time-dependent flows with a free surface J. Fluid Mech. 73, 603620.Google Scholar
Longuet-Higgins, M. S. 1980 On the forming of sharp corners at a free surface.Proc. R. Soc. Lond A 371, 453478.
Longuet-Higgins, M. S. 1981 A parametric flow for breaking waves. In Proc. Intl Symp. on Hydrodynamics in Ocean Engineering, Trondheim, Norway, vol. 1, pp. 121135. University of Trondheim.
Longuet-Higgins, M. S. 1982 Parametric solutions for breaking waves J. Fluid Mech. 121, 403424.Google Scholar
Longuet-Higgins, M. S. & Cokelet, E. D. 1976 The deformation of steep surface waves on water. I. A numerical method of computation Proc. R. Soc. Lond. A350, 126.Google Scholar
Miller, R. L. 1976 Role of vortices in surf zone prediction: sedimentation and wave forces. In Beach and Nearshore Sedimentation (ed. R. A. Davis & R. I. Ethington), pp. 92114. Soc. Econ. Paleontologists and Mineralogists Spec. Publ. 24.
New, A. L. 1983 On the breaking of water waves. Ph.D. thesis, University of Bristol.
Peregrine, D. H., Cokelet, E. D. & Mciver, P. 1980 The fluid mechanics of waves approaching breaking. In Proc. 17th Conf. Coastal Engng, Sydney, pp. 512528. A.S.C.E.