Experimental study on the efficiency of a navigable wave-energy converter with a variable water column

Abstract

Aiming at the problems of existing wave energy technology, such as high cost and poor survivability, this paper introduces a new wave-energy converter with a variable water column for propelled capability. This converter consists of a buoyancy tank, vertical pipe, horizontal pipe, and sluice gate, among others. By opening and closing the sluice gate, the length and shape of the water column in the converter are changed, resulting in a change in the motion resistance. The effects of the changes in the length and shape of the water column and the way of airflow work on the conversion characteristics of the system are studied experimentally, and a set of quantitative criteria is proposed to evaluate the conversion characteristics of the converter. The results of flume experiments show that the maximum capture width ratio reaches 154.6% for regular waves and 97.0% for random waves. The capture width ratio of the gate-opening converter is about 1/2 that of the gate-closing converter under regular waves and about 1/2 under random waves.