Based on a hybrid method coupling FNPT-based QALE-FEM and CFD, a self-developed solver QaleFoam is applied to generate the focused wave and simulate the motion response of the floating offshore wind turbine (FOWT), and the discontinuous Galerkin finite element method is used to obtain the force and moment of the mooring system in every time step. The static equilibrium tests of the wind turbine with and without mooring are carried out first. Then, three decay tests in the freedom of heave, surge, and pitch are carried out. Finally, the focused waves are generated, and the interaction between the focused wave and the FOWT with the mooring system is simulated. All the computed results are compared with the experimental results for validation.


The energy crisis is a common problem faced by many countries all over the world. With a reduction of non-renewable energy resources, the development of marine energy has become an inevitable trend. Offshore wind turbines play an important role in the development of marine resources. Floating offshore wind turbine (FOWT) is a widely used offshore wind power technology. In the deep-water area, the nonlinearity of the wave is enhanced and the wave is steep, which is easy to produce phenomena like focusing waves. Such a strong nonlinear wave is a threat to the platform structure, and it will affect the operation performance and fatigue life of FOWT. Therefore, the accurate simulation of the interaction of FOWT with the focusing wave is meaningful for the development and design of FOWT.

Research on nonlinear hydrodynamic characteristics of FOWT begins as early as the 12th century, and the study of the FOWT accelerates with the development of computer science in the past decades. Withee (2004) designed a conceptual offshore wind turbine and proposed a fully coupled method to analyze the dynamics. On this basis, Nielsen (2006) proposed a FOWT model and studied the stress of the fan blades. Zambrano et al. (2006) analyzed the swaying motion of the floating platform with steel rope mooring, and the impeller of the wind turbine was simplified and its rotation was ignored. Bayati et al. (2014) evaluated the effects of second-order hydrodynamic force on the semi-submersible floating wind turbine by analyzing the system load response caused by second-order hydrodynamic forces. Liu et al. (2016) used the open-source CFD tool OpenFOAM to study the aerodynamic influence of floating wind turbines by taking the motion response of the platform into account. Zhou et al. (2019) applied numerical models to conduct a detailed study on the hydrodynamic performance of offshore wind turbines slammed by focusing waves. López-Queija et al. (2022) proposed a simplified linear time-domain numerical model of higher accuracy to predict the system motion of FOWT in random waves, and the numerical method is verified by comparison with the experimental data. Lamei et al. (2022) studied the kinematic, aerodynamic, and hydroelastic response of a fully flexible offshore wind tracking floating wind turbine under the combined action of wave and wind load, and the configuration of the mooring system is optimized.

This content is only available via PDF.
You can access this article if you purchase or spend a download.