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Bragg scattering of surface waves by periodic bars: theory and experiment

Published online by Cambridge University Press:  21 April 2006

Tetsu Hara  and
Chiang C. Mei
Tetsu Hara
Affiliation:
Department of Civil Engineering, University of Tokyoand Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Chiang C. Mei
Affiliation:
Department of Civil Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Abstract

We extend a recent linearized theory on Bragg scattering of surface waves by periodic sandbars to include second-order effects of the free surface and of the bars. New experiments are performed to verify the existence of the cutoff detuning frequency, the dispersive nature of the first-order wave envelope, and the radiation of second-order long waves. Measured transient and quasi-steady responses to incident wave packets and uniform wavetrains are compared with corresponding theoretical results. For quasi-steady incident waves of relatively small steepness it is found necessary to improve the theory to the second order in bar slope, in order that the calculated short-wave envelopes agree with those measured over the bars.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 178 , May 1987 , pp. 221 - 241
Copyright
© 1987 Cambridge University Press

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