The combined development of offshore wind energy and marine aquaculture has gradually drawn attention and become a research focus in consideration of saving space resources and reducing costs. Therefore, a novel integrated structure including the offshore wind turbine (OWT) and aquaculture cage is proposed, and its hydrodynamic responses under complicated sea conditions are investigated. As is known, the hydrodynamic analysis of monopile-supported OWT has been widely studied by the computational fluid mechanics (CFD) method, while the corresponding analysis of the integrated structure is rarely executed. Meanwhile, the combined wave-current loading should be considered in the hydrodynamic analysis for reproducing the real ocean environment loading. Hence, in this study, a module utilized to generate the combined wave-current loading is self-developed in the open-source module "waves2Foam", and the numerical model of integrated structure including the monopile-supported OWT and aquaculture cage made of ultra-high molecular weight polyethylene (UHMWPE) are established in open-source software "OpenFOAM", which is referred from and verified by experiment. Subsequently, the hydrodynamic behaviors of the integrated structure subjected to wave-current loading are investigated in detail. It is noted that the influences of the UHMWPE cage on the pressure and wave-up of the monopile are significantly enlarged when applying the combined wave-current loading compared to the wave loading only.
Renewable energy has played a pivotal role in contemporary energy security strategies due to the attention on the environment and energy shortages, with a notable emphasis on wind energy in recent decades (Diaz and Soares, 2020). The offshore wind turbine (OWT) has emerged as a widely adopted solution for converting wind energy (He et al., 2016), recognized for its commendable stability and safety (Cai et al., 2023). In the complex marine environment, various types of foundations are applied to fix the OWT, where the monopile-supported foundation is the usual selection (Wu et al., 2019).
Extensive investigations on the monopile-supported OWT have been executed by numerous researchers, where the nonlinear wave theory was commonly applied in researching the interaction between wave and OWT (Schløer et al., 2016). The experimental investigation on the monopile-supported OWT subjected to regular or irregular nonlinear waves was conducted, where the wave slamming force and pressure distribution were discussed (Zhu et al., 2022a). Besides wave forces and pressure distributions, wave run-ups on the monopile-type foundation were also considered in the hydrodynamic analysis (Tang et al., 2021). The wave run-up and wave load on the monopile-supported OWT under regular nonlinear waves were studied by simulating through the CFD method, calibrating a semi-empirical run-up formula in special regular nonlinear wave conditions (Lin et al., 2017). Recently, several studies applied the combined wave and current loading condition in investigations on the monopile-supported OWT through experiments (Zhang et al., 2022) and numerical simulation (Wang et al., 2022).
