Optimization of a three-dimensional hybrid system combining a floating breakwater and a wave energy converter array

Combining wave energy converters (WECs) with a floating breakwater provides a potential approach to help develop commercial-scale wave power operations. This paper aims to design and optimize a three-dimensional floating breakwater integrated with a WEC array by developing a numerical model of a multi-floating-body coupled system based on potential flow theory with viscous correction in the frequency domain. By analyzing the wave surface elevations around the breakwater, the size of the breakwater was optimized and the optimal installation locations of the WECs were determined. Under the condition of coupled constraints and six degrees-of-freedom motion, the interactions between the WEC array and the breakwater were analyzed. Subsequently, the number of WECs and the distance between the WECs and the breakwater were optimized to maximize the wave energy conversion performance of the hybrid system. Results show that the wave focusing areas appear more frequently near the breakwater. These focusing areas significantly improve WEC power, and thus better wave energy conversion performance can be achieved when the WECs are placed close to the breakwater. The vertical forces on the breakwater significantly increase due to the presence of the WECs, however the horizontal forces are decreased. The findings of this paper provide guidance to design and optimize a hybrid WEC-breakwater system in practical engineering applications.