This paper aims to investigate the wave resonance in the WECbreakwater gap of a dual-body hybrid system using the Star-CCM+ software. The effects of the narrow gap wave resonance on the performance of the dual-body hybrid system and the forces on the breakwater are studied. The influence of the WEC motion and the gap width of the hybrid system on the wave elevations are analyzed. Results reveal that the wave resonance in the WEC-breakwater gap significantly improves the wave energy extraction performance of the hybrid system, but has little impact on the wave attenuation performance of the hybrid system.
The high construction cost and low extraction performance of the Wave Energy Converters (WECs) reduce the economic competitiveness of the wave energy, which constrains the development of the commercialscale wave power operations. Combining WECs with the breakwater can provide an effective solution to make the wave energy economically competitive and promote the development of WECs and floating breakwaters (Mustapa et al., 2017; Zhao et al., 2019).
One of the widely studied integrated WEC-breakwater system is Oscillating-Buoy (OB) type WECs integrated with floating breakwaters, which mainly includes the single-floater integrated system (Ning and Zhao, 2016; Madhi et al., 2014; Zhang et al., 2020a) and the dual-body hybrid system (Zhao and Ning, 2018; Ning et al., 2019; Reabroy et al., 2019). The existence of the gap between two floaters of the dual-body hybrid system is one of main differences comparing with the singlefloater integrated system. The wave surface in the gap between two structures oscillates and the wave response amplitude can reach the maximum under certain wave frequency, which is called wave resonance in the narrow gap. The wave resonance in the gap between two floaters of the dual-body hybrid system can significantly affects the performance of the WEC. Thus, it is essential to study the influence of the gap wave resonance on the performance of the hybrid system.