Comparative Analysis of Seakeeping of Offshore Photovoltaic Floating Unit

Background: In recent years, offshore photovoltaic (PV) power systems have become an emerging hot issue. For offshore PV, the marine environmental loads are more complex, especially wave loads will put higher demands on the mooring system, and a failure of the mooring system will cause great harm. In order to ensure the safe operation of the system, the floating unit should be designed for high seakeeping. Objective: In this paper, six common configurations of floating units are selected, and the six configurations are divided into two experimental groups, one of which includes floating units with different shapes of holes, and mainly discusses the effects of different shapes of holes on the seakeeping of floating units, and the other experimental group includes common configurations of catamarans and trimarans in ships, and mainly discusses the effects of different bottom structures on the seakeeping of floating units. And after determining the better configuration, further shape optimization is performed. Methods: The problem described in this paper cannot ignore the change of the solid deformation on the flow field boundary, when both interaction processes between the two phases need to be calculated. Therefore, this paper discusses a bi-directional fluid-solid coupling process. For the six float units, a bi-directional fluid-structure coupling calculation analysis was carried out with high seakeeping as the research objective, and the effects of different float unit configurations on the seakeeping performance of floats were discussed. Results: Ultimately, the trimaran configuration is considered to have better seakeeping performance than the remaining configurations among the six configurations. On this basis, the bottom structure of the trimaran configuration was further optimized, and the cross-sectional shape of the bottom structure with better seakeeping performance was obtained. Conclusion: The wave resistance of the trimaran configuration was calculated to be superior compared with other configurations. The cross-sectional shape of the bottom structure of the trimaran was further analyzed. It is concluded that the trimaran structure with a bottom structure cross-section whose bottom edge is at an angle of 0° with the horizontal plane has the best wave resistance. It provides some guidance for the design of similar marine structures with high seakeeping.