The development of wind turbine towards to larger-scale and floating type, leading to the significant impact on the aerodynamic performance and fatigue load of the wind turbine induced by the complex atmospheric inflow. In this study, the numerical investigation of floating wind turbine (FOWT) under complex atmospheric boundary layer (ABL) inflow is performed. The NREL 5MW reference turbine mounted on the OC4 floating platform is adopted as the research object. Large eddy simulations (LES) combined with the actuator line model is used for the wind turbine blades numerical simulation, and the platform motions are solved by the potential theory. The complex ABL inflow is generated using a precursor LES method with long-enough time to obtain the quasi-equilibrium state turbulence. And the calculation results are compared with the uniform wind inflow. The oscillation amplitude of the rotor power for FOWT under uniform inflow does not exceed 40% with the excitation of regular incident wave, while the amplitude for ABL inflow reaches up to 100%. Long-term significant response of rotor power is observed because of the large-scale high-velocity airflow upstream the turbine rotor plane. The later asymmetric distribution of ABL inflow velocity is responsible for evidently response of aerodynamic yaw moment amplitude. For the floating platform motions, the oscillating amplitude of yaw motion for ABL inflow is over 2°, while the output value for uniform inflow is steady and does not exceed 0.2°. The differences of the other five platform motions are not significantly observed.
In recent years, the traditional fossil resources are gradually difficult to meet the significant demand of energy with the greatly development of society. However, wind energy has received increasing attention due to the properties of non-polluting, renewable and large reserves [1], which is responsible for the prosper growth of the wind turbine technology. According to the 2021 Global Wind Energy Report[2], the installed capacity of wind turbine in 2020 reached up to 93GW, resulting 53% growing compared with the last year. The development trend of wind turbine is gradually towards to large-scale and floating type, leading to the significant impact on the aerodynamic performance and fatigue load of the wind turbine induced by the complex atmospheric boundary layer (ABL) inflow. Therefore, the numerical simulation for studying the operation performance of FOWT under the complex ABL inflow is very necessary.
