Experimental Study on Three Dimensional Wave Overtopping Control Structures for Wave Energy Converter

Abstract

Waves incoming to coastal area can be amplified, swashed and overtopped by wave control structure, resulting in a conversion of the kinetic energy of wave motion into the potential energy of a static head between mean sea level and elevated water surface in reservoir. If the sufficient quantity of overflow is conserved in the reservoir, static water head can be utilized to produce hydroelectric power generation. This study is aim to optimize the shape of wave overtopping structure which results in efficient wave overtopping. Two dimensional wave overtopping experiments were carried out first to investigate the effects of 2-D shape parameters of the ramp slope ( ), relative freeboard height ( ) and relative length of the ramp ( ) (Shin and Hong, 2005). Then, the most efficient 2-D structure resulted from 2-D experiments was modified to three dimensional structures with different ratios between entrance and exit widths (b and B) of the ramp, and the effect of wave focusing of the 3-D shape parameter were investigated in 3-D wave tank. The wave overtopping flow rate was analyzed in terms of shape parameters. It was found that the ramp slope and relative freeboard are rather dominant parameters than the width ratio.