Numerical investigations of coupled aeroelastic performance of wind turbines by elastic actuator line model

Abstract

With the economic considerations of wind power generation, blades of wind turbines are gradually becoming longer and more flexible. Therefore, it is necessary to research the influence of coupling aerodynamic and elastic structure of blades of wind turbines. Moreover, in a wind farm, the turbulent wind is generated by the irregular movement of the atmosphere, which makes the elastic deformations of blades and the complex wake interference effect between wind turbines. Therefore, the coupled aeroelastic performance of the blade is applied to analyze the interaction of the wake flow field of two tandem wind turbines based on the elastic actuator line model and the Euler-Bernoulli beam theory. Firstly, the correctness of the coupled aeroelastic model is illustrated by comparing the aeroelastic response with OpenFAST software. Secondly, the influence of aeroelastic performances is researched on the structural deformations of blades. It is found that the aerodynamic power and thrust decrease after considering the deformations of blades. Furthermore, the interference effect on the thrust is more evident than aerodynamic power. Thirdly, the far wake region is affected apparently when the deformations of blades are taken into consideration, which causes the tip vortex interference phenomenon to delay. Finally, compared with the uniform inflow condition, the displacement and speed of the deformations of the blades are both increased under the turbulent inflow condition. Meanwhile, the disturbance of the wake vortex in the far wake region by the turbulent wind is stronger. Besides, by comparing the differences between the four vortex identification methods, it is significant that the ΩR method can better capture the vortex system behind the rotor plane without manual intervention threshold selection. The vortex structure also represents the vorticity of the wake vortex evolution.