Angle of attack is the most important parameter to determine the aerodynamic behaviors of wind turbine blades. It is difficult to be measured in the field and also ever-changing due to the unsteady inflow condition and dynamic control responses. In this work, a prediction method on the uncertainty of angle of attack was proposed only with the conventional wind turbine SCADA data and validated by the careful measurements in the field with leading-edge probes. As a result, in standstill case, the angle of attack fluctuates quasi-periodically and the amplitude is determined by yawing angle. In normal operating case, The standard deviation of angle of attack decreases from root to tip as the quintic polynomial law. The blade can be divided into three regions based on the contributions of three variables. The dominant variable from root to tip is yawing angle, tip-speed ratio and pitching angle, respectively. With the prediction method, the fluctuations of angle of attack along the blade span can be evaluated quickly for the wind turbine in the services. Also, in the design phase of a new wind turbine, the operation range of angle of attack can be pre-evaluated based on the wind speed, direction and control algorithm.

中文翻译：

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基于现场实测的风力机叶片迎角不确定度预测

攻角是决定风力机叶片气动性能的最重要参数。由于流入条件和动态控制响应的不稳定，难以在现场测量并且还不断变化。在这项工作中，仅使用传统的风力涡轮机 SCADA 数据提出了一种对攻角不确定性的预测方法，并通过前沿探头在现场的仔细测量进行了验证。因此，在静止情况下，迎角呈准周期性波动，幅度由偏航角决定。在正常工作情况下，攻角的标准偏差从根部到尖端按照五次多项式定律递减。根据三个变量的贡献，叶片可以分为三个区域。从根部到尖端的主要变量分别是偏航角、尖端速比和俯仰角。使用预测方法，可以快速评估服务中风力涡轮机的攻角沿叶片跨度的波动。此外，在新风机的设计阶段，可以根据风速、风向和控制算法对迎角的运行范围进行预评估。