The use of combined wind and wave energy harvesting devices (CWWHDs) is an effective way to synergistically capture offshore wind and wave energy. However, the form of combined energy harvesting and coupled simulation techniques limit the development of CWWHDs. This paper classifies the existing CWWHDs based on wave energy converters and offshore wind turbines, summarizes the theoretical background and implementation forms of the numerical simulation of CWWHDs, and focuses on the technical details of wind-wave coupling and multi-body coupling simulation, which fills the gap in the research of the wind-wave coupling and multi-body coupling numerical simulation of CWWHDs. Finally, the current research focus and development direction of CWWHDs and their numerical simulation technology are summarized to provide a reference for the future development and application of CWWHDs and numerical simulation technology.

Floating offshore wind turbines (FOWTs), particularly the 15 MW wind turbine variant represented by the IEA 15 MW wind turbine, are the focal point of this study. This study addresses design and testing challenges in deep-marine environments. An initial analysis examines the shortcomings of three main propulsion systems under mismatched Froude and Reynolds numbers. Subsequently, a novel multi-fan aerodynamic load actuator (NMALA) suitable for 15 MW FOWTs is proposed, featuring a design structure, mathematical model, and hardware specifications. Utilizing a robust regression algorithm, the mathematical model of NMALA produces inverse formulas for aerodynamic loads. Simulation experiments using FAST and MATLAB validate the accuracy of the structure and inverse formulas for NMALA under a time step of 0.1s. Future studies could enhance understanding by exploring the impact of environmental factors on motor and propeller hardware, and by constructing a physical NMALA platform to conduct Real-Time Hybrid Model (RTHM) tests on 15 MW FOWTs. This study contributes to advancing the development of high-capacity FOWTs for efficient harnessing of offshore wind energy resources. By considering the intricate interplay between wind and wave forces and proposing innovative solutions such as NMALA, this study lays the foundation for further advancements in offshore wind turbine technology, ultimately contributing to the global transition towards sustainable energy sources.