Wave Energy Absorption Characteristics of Circular Air-Chamber for Use of Light Beacon Fixed on Sunken Rock

Summary

The light beacon which is installed on the sunken rock, etc.as navigation aid has great difficulty in securing power supply because of its installing location.

The research project concerns both with the experimental investigation on the performance of circular air chamber and that of air turbine, which means a technical extension of the light buoy technology which already has been realized as only case successfully utilizing wave energy.

This paper deals with the first stage of the investigation, i.e., the power absorbing characteristics of circular air chamber in order to squeeze wave energy efficiently even in the calm or moderate sea state throughout a year.

The circular air chamber is attached around circular base as shown in Fig. 1 and is divided into two or four chambers.

In the experiment a 1/5 scale model has been used in the Offshore Structure Experimental Basin of Ship Research Institute, and the wave power absorbing efficiencies for each air chamber have been measured for various wave directions, wave periods and heights, water-line levels and so on. As the results, it is clarified that this system can generate sufficient power for use of the light beacon. Furthermore, absorbed wave energy was calculated by use of the equivalent floating body concept and compared with experimental values.