Free-stream turbulence characteristics play an important role in the mechanisms of power harvesting for wind turbines. Acquisitions of power and thrust from a model wind turbine of diameter 0.18 m have been carried out in a wind tunnel for a wide range of turbulent base flows, with varying free-stream turbulence intensity in the range between 3% and 16% and integral timescale spanning from 0.1 to 10 times the turbine rotation period. The results demonstrate that power is significantly affected by both the inflow turbulence scales and its intensity, while thrust is scarcely affected by free-stream turbulence. Fluctuations in the generated torques are also measured, with their behavior dominated by the free-stream turbulence scale, and only moderately affected by turbulence intensity. The frequency response of thrust fluctuations has been measured for a selected subset of operating conditions, demonstrating that the turbine thrust is unaffected by high-frequency components in the inflow. Conclusions are drawn on the necessity to match both turbulence intensity and base flow frequency content in wind tunnel studies if realistic results are to be obtained from small-scale studies.

中文翻译：

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自由流湍流对模型风机性能的影响

自由流湍流特性在风力涡轮机的功率收集机制中起着重要作用。已经在风洞中从直径为0.18 m的模型风力涡轮机中获取了功率和推力，以用于各种湍流基流，自由流湍流强度在3％到16％之间变化，并且积分时标范围是涡轮旋转周期的0.1到10倍。结果表明，动力受到流入湍流尺度及其强度的显着影响，而推力几乎不受自由流湍流的影响。还测量了所产生转矩的波动，其行为受自由流湍流标度支配，并且仅受到湍流强度的适度影响。已针对选定工况子集测量了推力波动的频率响应，这表明涡轮机推力不受流入流体中高频分量的影响。如果要从小规模研究中获得实际结果，则必须得出结论，即在风洞研究中必须同时匹配湍流强度和基流频率含量。