SHOCK PRESSURE OF BREAKING WAVE

Hisashi Mitsuyasu

Abstract


Shock pressure due to breaking wave was studied experimentally and analytically for the case of two-dimensional regular oscillatory wave. In the first part of this paper, important characteristics of shock pressures were described, which were obtained by using the newly designed pressure gauges of very high frequency responces ( 10 ~ 10000 c/s ). And the following two points were mainly examined l) the detailed characteristics of pressure-time histories of shock pressures, and li) the similarity of pressure-time histories observed simultaneously with two separated gauges. In the second part of this paper, the dynamical models representing the generation mechanism of shock pressure were examined to explain the observed properties of shock pressures, in which the new air-cushion model extended from the original air-cushion model of Bagnold (1939) was included. Under the assumption of small compression of the air cushion, the analytical solutions representing the pressure-time histories were obtained both for the original model of Bagnold (1939) and for the present new model. For the cases of relatively high-intensity shock pressures, the consistent results were obtained by analyzing the observed shock pressures by the new air-cushion model. The discussion of shock pressure due to finite compression of air cushion was also included.

Keywords


shock pressure; wave breaking

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