MECHANICS OF BEACH DEFORMATION DUE TO BREAKING WAVES

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1. Experiments on characteristics of breaking waves: Experiments were carried out by using four kinds of deep-water wave steepness, that is the values of 0.019 to 0.048. The wave profiles of the breaking waves and the velocities near breaking points were measured on the slope of 1/15. A summary of the results is as follows:(1) It was clarified that a new instrument of calibration for hot-film velocity meter, which was developed in this study, is available to calibrate easily. (2) The phenomena of ejection or sweep which are related to the generation and development of turbulence due to breaking waves were found by the time variation of Reynolds stresses measured near the breaking point. (3) In the case of large values of deep-water wave steepness, it is shown that the turbulence is propagated to the offshore region of breaking point by investigating the variation of the fluctuating turbulent velocity components.2.Deformation of two-dimensional beach profiles: Experiments on beach profile deformation were conducted by the same condition with that of dreaking waves. The results obtained are summarized as follows:(1) Two-dimensional beach profiles may be expressed in terms of the orthogonal polynomial macroscopically. (2) It is clarified that on-offshore sediment transport rate is calculated by applying the orthogonal polynomial. The results agree with those of previous studies macroscopically, except the randam variation of beach profiles.