Numerical Study of Motion Responses of a New Combined Floating Wind Turbine and Wave Energy Converters

Abstract Improving power generation efficiency and reducing development costs is one of the main challenges for the floating offshore wind turbine (FOWT). A similar set of challenges is encountered in wave energy converter (WEC) systems. In response, this paper proposes a novel hybrid concept that combines FOWT and oscillating water columns (OWC) to capitalize on their respective advantages, as substantiated through a comprehensive numerical comparison with a purely FOWT system. The hybrid concept’s advantages are underscored by a rigorous analysis that incorporates wave-induced loads on the semi-submersible floating foundation and OWC using the potential theory, encompassing the 1st and 2nd order excitation forces as well as radiating added mass and damping, all integrated within the AQWA code. Viscous effects are approximated via the empirical Morison equation. Furthermore, the aerodynamic impact of the turbine blades is meticulously simulated using the blade element momentum method within the FAST code. Pitch and Nacelle horizontal acceleration of system are identified as the primary criterion for illustrating the advantages of the hybrid concept. In addition, this paper conducts a comparative study that explores the impact of sizing OWC in hybrid systems, shedding light on the potential for optimizing system motion performance and improving cost efficiency while maintaining constant structural weight. The paper culminates in a proposed arrangement plan, serving as a fundamental reference for the design of future offshore wind turbine systems.