An experimental study of steep solitary wave reflection at a vertical wall
Résumé
Until now very few experimental investigations have been conducted to study the reflection of steep solitary waves at a vertical wall whereas many theoretical analysis and numerical simulations were developed in the past. The
use of experimental techniques to capture the waveform and associate phenomena during the short-time head-on collision of two solitary waves (or the reflection of a solitary wave by a vertical wall) is not an easy task. Solitary waves with amplitude a/h ≤ 0.556 are experimentally generated by a piston type wavemaker. We have used a high speed camera and our experimental results were compared with previous studies, including both theoretical investigations and numerical simulations. We found that previous theoretical results underestimate wave run-up characteristics (maximal run-up amplitude, attachment and detachment times, wall residence time), except the third-order result of Su & Mirie [1] who calculated maximal run-up which is in good agreement with experiments. Within the range of solitary wave amplitude considered experimentally, present measurements are in excellent agreement with numerical results of Cooker et al [2] and Chambarel et al [3]. Furthermore, for very steep solitary waves we found numerically the occurrence of a Rayleigh-Taylor instability on the top of the jet due the collision.
A theoretical explanation of the existence of this instability is given.