We present a modified version of the ONERA dynamic stall model for improving the prediction of the unsteady forces and load overshoots generated by the shedding of dynamic stall vortices. The modifications include modeling the chord-axis forces instead of the wind-axis forces used originally. A novel approach for defining the onset of a dynamic stall is based on the behavior of the chordwise force without correlating the onset empirically. Overshoots in the unsteady aerodynamic loads caused by vortex shedding are modeled by sine-shaped functions added to the normal force and moment. The onset and duration of these pulses are empirically described in the time domain for convenient use in time-marching simulations. The modified dynamic stall model is calibrated using a genetic algorithm and compared to experimental data of different airfoils relevant to wind turbine applications. The results show an excellent correlation with the experimental data, particularly in deep dynamic stall, which are characterized by large fluctuations in the aerodynamic loads.

中文翻译：

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对振荡翼型的动态载荷进行建模，重点是动态失速涡

我们提出了一个修改版的 ONERA 动态失速模型，用于改进动态失速涡旋脱落产生的不稳定力和负载超调的预测。修改包括模拟弦轴力，而不是最初使用的风轴力。一种定义动态失速开始的新方法是基于弦向力的行为，而不是根据经验将开始相关联。由涡旋脱落引起的非定常空气动力载荷的过冲通过添加到法向力和力矩的正弦函数建模。这些脉冲的开始和持续时间在时域中凭经验描述，以便在时间推进模拟中使用。修改后的动态失速模型使用遗传算法进行校准，并与与风力涡轮机应用相关的不同翼型的实验数据进行比较。结果显示与实验数据具有极好的相关性，特别是在深度动态失速中，其特征在于气动载荷的大波动。