The Invariants of Water Waves Breaking On Beaches with Variable Slope
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University of Lagos
The breaking of water waves is examined experimentally on four different laboratory beach slopes of 1:40, 1:20, 1:10 and 1:5. Several measurements of shoalling variables are made in the wave tank both before and after wave breaking. The variables measured in the breaker zone include breaker height and depth, plunge point (when applicable), breaker travel distance, end of aeration, run-up and run-down points. Graphical techniques and the statistical method of least squares are used to investigate the various relationships that exist between breaker and deep sea parameters. In order to make the conclusion of the analysis undertaken to be of wider applications, the data published on the subject by several accredited investigators such as Iversen (1952). Galvin (1968), Iwagaki et al (1974) and Van Dorn (1978) are re-analysed and their results are compared with those arrived at through the analysis of the data obtained in this experimental investigation. In several cases, the agreement is remarkably close. On the whole, the joint analysis of the data from the study with those of the other investigators present a more complete picture of the shape and kinematics of breaking waves. In the shoalling Zone where turbulence limits the application of detailed analysis, the laws of motion are derived as time and depth averaged equations. A numerical model is also developed that uses one form of the two dimensional Boussinessq equations formulated in terms of mass and momemtum conservation laws. Differential equations are approximated by finite difference scheme that employs a three level preissmann scheme so as to provide the high order of accuracy needed to simulate the various non-linear terms of the governing equations. The numerical model developed is used to simulate the propagation of solitary waves in a channel of constant depth averaged equations.
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Graphical techniques , Statistical method , Numerical Model , Turbulence
Oyegoke, S.E (1982) The Invariants of Water Waves Breaking On Beaches with Variable Slope. University of Lagos School of Postgraduate Studies Phd Civil Engineering Thesis and Dissertation Abstracts, 157p.