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Reflection of water waves in a channel with corrugated bed

Published online by Cambridge University Press:  21 April 2006

T. Brooke Benjamin
Affiliation:
Mathematical Institute, 24/29 St Giles, Oxford OX1 3LB, UK
B. Boczar-Karakiewicz
Affiliation:
I.N.R.S.-Océanologie, Université du Québec, Rimouski, Québec G5L 3A1, Canada
W. G. Pritchard
Affiliation:
Department of Mathematics, Pennsylvania State University, University Park, PA 16802, USA

Abstract

Intended as a contribution towards understanding the multiple processes entailed in the development of coastal sand bars due to wave action, this theoretical and experimental study deals with the Bragg reflection of long-crested surface waves in a water channel whose bed is corrugated sinusoidally. The present findings complement and in a few respects improve upon those in previous investigations, particularly Davies & Heathershaw (1984).

In §2 a linearized theory is presented, being directed to the elucidation of experimental situations where monochromatic waves propagate into a channel with a limited stretch of corrugations on its bed and an imperfectly absorbing beach at its far end. Allowance is made fully for dispersive effects (§2.2) and approximately for small frictional effects (§2.3). Points of interpretation (§2.4) include accounts of degenerate but non-trivial solutions that apply at frequencies terminating the stopping band, wherein the spatial wavefield has an exponential envelope. The experimental results presented in §4 derive from measurements of the wavefield over a stretch of 24 corrugations, at various frequencies both inside and outside the stopping band. Quantitative comparisons (§4.2 and 4.3) demonstrate close agreements with the theory.

Type
Research Article
Copyright
© 1987 Cambridge University Press

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References

Barnard, B. J. S. & Pritchard, W. G. 1972 Cross waves. Part 2. Experiments. J. Fluid Mech. 55, 245256.Google Scholar
Bona, J. L., Pritchard, W. G. & Scott, L. R. 1981 A comparison of laboratory experiments with a model equation for water waves. Phil. Trans. R. Soc. Lond. A 302, 457510.Google Scholar
Briillouin, N. 1953 Wave propagation in periodic structures. Dover.
Buchan, S. 1979 Edge waves on plane beaches. M.Sc. dissertation, University of Essex.
Davies, A. G. & Heathershaw, A. D. 1984 Surface-wave propagation over sinusoidally varying topography. J. Fluid Mech. 144, 419443.Google Scholar
Elachi, C. 1976 Waves in active and passive periodic structures: a review. Proc. IEEE 64, 16661698.Google Scholar
Kirby, J. T. 1986a A general wave equation for waves over rippled beds. J. Fluid Mech. 162, 171186.Google Scholar
Kirby, J. T. 1986b On the gradual reflection of weakly nonlinear Stokes waves in regions with varying topography. J. Fluid Mech. 162, 187209.Google Scholar
Lau, J. & Travis, B. 1973 Slowly varying Stokes waves and submarine longshore bars. J. Geophys. Res. 78, 44894497.Google Scholar
Mahony, J. J. & Pritchard, W. G. 1980 Wave reflexion from beaches. J. Fluid Mech. 101, 809832.Google Scholar
Mei, C. C. 1985 Resonant reflection of surface waves by periodic sandbars. J. Fluid Mech. 152, 315335.Google Scholar
Mitra, A. & Greenberg, M. D. 1984 Slow interactions of gravity waves and a corrugated bed. Trans. ASME E: J. Appl. Mech. 51, 251255.Google Scholar
Rhines, P. 1970 Wave propagation in a periodic medium with application to the ocean. Rev. Geophysics Space Phys. 8, 303319.Google Scholar
Saylor, J. H. & Hands, E. B. 1970 Properties of longshore bars in the Great Lakes. Proc. XII Conf. Coastal Engng vol. 2, pp. 839853.
Short, A. D. 1975 Multiple offshore bars and standing waves. J. Geophys. Res. 80, 38383840.Google Scholar
Stoker, J. J. 1957 Water waves. Interscience.
Ursell, F., Dean, R. G. & Yu, Y. S. 1960 Forced small-amplitude water waves; a comparison of theory and experiment. J. Fluid Mech. 7, 3352.Google Scholar