Hydrodynamic Investigation of a Dual-Cylindrical OWC Wave Energy Converter Integrated into a Fixed Caisson Breakwater

Abstract

A fixed dual cylindrical oscillating water column (OWC) acting as a breakwater-type wave energy converter (WEC) is proposed to harvest the wave energy effectively for shallow offshore sites. An analytical model is developed to investigate the hydrodynamic characteristics and the energy capture capacity of the cylindrical OWC device in severe waves. Based on the linear potential flow theory, the analytical solutions of the velocity potential in diffraction mode are solved by matching the Eigen-function expansion technique, and the continuous conditions of the velocity potential and fluid velocity between the computational sub-domains are involved in solving the problem for determining a solution. The proposed model is verified against the published data. The effects of the wave height, the angle of chamber clapboard and the radius of the inner and outer cylindrical column on the energy conversion efficiency are investigated in this paper. To improve the energy conversion performance and obtain a faster prediction for structural optimization of the cylindrical OWC, the geometrical parameters are further discussed in the analytical model. The results indicate that the geometrical parameters of the chamber have significant effects on the wave energy absorption efficiency. It is found that the effective frequency bandwidth of the dual cylindrical column can be broadened by improving the angle of the chamber clapboard and the inner–outer cylinder diameter ratio.

Review of the Influence of Oceanographic and Geometric Parameters on Oscillating Water Columns

“…An optimum chamber volume exists and it should be calculated for each case. Wang et al (2020) studied the wave loads on a land-based dual chamber OWC using a nonlinear numerical model and they reached the following conclusions [78]:…”

Experimental investigation and performance comparison of a 1 single OWC, array and M-OWC

“…Concerning the terminating array, multiple OWCs, not necessarily as an M-OWC, but in integrated applications such as in fixed shoreline defence or breakwater applications are becoming popular as a research topic as can be seen in the modelling by Refs. [22,23]. The OWC array as an M-OWC in large floating breakwaters is also becoming relevant with recent work in Ref.…”

Design Selection and Geometry in OWC Wave Energy Converters for Performance

“…When the OWC is designed to be isolated, the cylindrical shape is one of the most common alternatives given that this solution is not affected by wave direction [13]. It was proposed both for nearshore devices [14,15] as well as for hybrid wind-wave applications [16]. Hybrid wave farms combining OWC WECs with other wave energy conversion technologies have also been investigated [17,18].…”