Akiko Matsumura

Experiment on Tsunami Flow in Wave Basin

In this study, it is discussed about the method to generate a strong flow by tsunami in a wave basin. The authors are tried to adopt the vertical jet system and measured horizontal water particle velocities. Before the experiments, numerical analysis has done, and the vertical distribution of horizontal water particle velocity is estimated to be almost the same. However, the horizontal water particle velocity in the vicinity of the bottom was a little small in the experiment. But it is negligible because the flow velocity is very large compared with the flow generated by regular waves. Moreover, by controlling the volume of the jet periodically, the oscillating flow can be generated. Therefore, it is concluded that the vertical jet system can apply to the large scale tsunami experiments.

A COUNTERMEASURE AGAINST WAVE-OVERTOPPING USING SCRAP CONCRETE OF DAMAGED SEAWALLS

A lot of inundation of sea water has arisen at coastal zone in Japan recent years because of attacking larger tidal waves and storm surges than usual. Also there are many examples that a destruction of parapet could cause serious damage by increasing of overtopping to the coastal zone. When seawalls have been damaged, a lot of scrap concrete is generated. In this study, a countermeasure against wave overtopping using these scrap concrete of damaged seawalls is proposed and verified the validity of the facilities and equipments for countermeasures against disaster by hydraulic model tests. Furthermore a method for estimating overtopping over seawalls using CADMAS-SURF has applied to the model test and validated .