Response of Point-Absorbing Wave Energy Conversion System in 50-Years Return Period Extreme Focused Waves

This work evaluates the survivability of a point-absorbing wave energy converter at sea states along and inside the 50-year environmental contour for a selected-site in North Sea, by utilizing CFD simulations. Focused wave groups based on NewWave theory are used to model the extreme waves. The numerical breaking waves have been previously predicted by the analytical breaking criterion, showing that the latter provides an accurate estimate for the breaking state. The forces on key components of the device and the system’s dynamics are studied and compared. Slamming loads are identified in the interaction with extreme waves, particularly with breaking waves, and compared with the analytical formulas for slamming estimation as suggested by industrial standards. Considering the extreme wave characteristics, the accompanied phenomena and the resulting WEC’s response, this work contributes to the identification of the design-waves given the environmental contour of the selected site. The top-left side of the contour is identified as the more critical area as it consists of steep and high waves inducing significant nonlinear phenomena, resulting in high loads.The research in this paper was supported by the Centre of Natural Hazards and DisasterScience, Sweden, the Swedish Research Council (VR, Grant No. 2015-04657), the Swedish EnergyAuthority (project number 47264-1), and the Onassis Foundation (Scholarship ID: FZP 021-1/2019-2020). Erik Nilsson and Anna Rutgersson were funded partly by the Swedish Research CouncilFORMAS (Grant No. 2018-01784) and the Centre of Natural Hazards and Disaster Science (CNDS).