Abstract The aeroelastic coupling effect is playing an increasingly important role in the aerodynamic and aeroelastic characteristics of wind turbine blades owing to the increasing size of modern wind turbines. Concurrently, periodic unsteady inflows, including the wind shear (WS), tower shadow (TS), and yawed inflow, further amplify the impacts of aeroelastic coupling. In this study, an aeroelastic model based on the geometrically exact beam theory and blade element momentum method is established. The aeroelastic coupling model is verified based on several previous studies. Taking the NREL 5WM flexible wind turbine blade as an example, the aerodynamic and aeroelastic characteristics under periodic unsteady inflows are investigated. The results show that the WS causes remarkable fluctuations of the flap deflection and yaw moment. The TS effect introduces dramatic changes into the tilt moment, thrust force, and output power when the blade passes by the tower. The yawed inflow leads to a significant reduction in both the output power and thrust force. Compared with other unsteady inflows, the gravity effect on the output power and thrust force are negligible. The response under the combined effect is a summation of the results considering each single influencing factor and is dominated by the major influencing factors.

中文翻译：

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周期性非定常流入下柔性风力机叶片的气动和气动弹性特性

摘要 随着现代风力发电机的尺寸不断增大，气弹耦合效应对风力机叶片的气动和气动弹性特性的影响越来越重要。同时，周期性不稳定流入，包括风切变 (WS)、塔影 (TS) 和偏航流入，进一步放大了气动弹性耦合的影响。在这项研究中，基于几何精确梁理论和叶片单元动量方法建立了气动弹性模型。气动弹性耦合模型基于之前的多项研究得到验证。以NREL 5WM柔性风力机叶片为例，研究了周期性非定常流入下的气动和气动弹性特性。结果表明，WS引起襟翼偏转和偏航力矩的显着波动。当叶片经过塔架时，TS 效应会导致倾斜力矩、推力和输出功率发生巨大变化。偏航流入导致输出功率和推力均显着降低。与其他非定常流入相比，重力对输出功率和推力的影响可以忽略不计。组合效应下的响应是考虑每个单一影响因素的结果的总和，以主要影响因素为主导。