PROPOSAL OF A SELF-PROPELLED WAVEMAKER FOR TSUNAMI AND STORM SURGE EXPERIMENTS

Abstract

 After the 2011 off the Pacific coast of Tohoku Earthquake, the necessity of tenacious coastal/harbor structure has been pointed out. Although some investigations have been done experimentally, it is difficult to make waves similar to actual tsunami in hydraulic experiments. In this study, characteristics and feasibility of a self-propelled wavemaker is proposed and investigated using CADMAS-SURF/3D which is combined with the immersed boundary method. As a result, the following findings were obtained: 1) The magnitude of standing waves indued by the long-distance movement of a wave board in a water tank has approximately exponential relation with wave-making time, and the oscilallation with the natural frequency is predominant. 2) Regarding overflow phenomenon, it is possible to control overflow time and overflow depth by arbitrary movement of the wave board compared with the gate type generation. 3) When short period waves are made at the same time as water level rise, the period can be controlled by taking into account the Doppler effect. Consequently, it was shown that tsunami and storm surge experiments has more reality by the use of this wave generation system.