Optimal Design of Kaimei-type Wave Power Absorber

Abstract

Japan Marine Sience and Technology Center is putting into practice th e Kaimei project Phase II. The targets of this plan mainly include the field test of the turbine and generator, and the establishment of the phase control technique. The wave power device Kaimei is classified as the floating attenuator type using the air turbine and the generator. The performance of this device seems to depend on the arrangement of the air chambers and the buoyancy rooms, and also on the external loads. This study as a part of the project aims to extablish the design procedure of the optimal device form by predicting the power output and estimating the feasibility at the identified site and sea condition.In this paper the hydrodynamic forces are calculated by the singular distribution method and the performance is estimated by changing the fundamental form parameters. The results are following.(1) The wave power absorbing performance of the Kaimei type device is almost proportional to the areal ratio of the air chambers in an optimal external load condition.(2) By making the breadth of the device wide, we can expect the increasing performance.Further in order to assure the design procedure, the model experiment was made and compared with the analysis. Both agree well as a whole. However, the heaving and pitching motions of the floating device are made clear to badly affect on the performance. The author recommends the device form hard to move, or with the performance not susceptible of the motion of the floating device.