A new approach is proposed to do the velocity sampling for actuator-line models (ALM). Unlike the conventional spatial averaging approaches, the velocity sampling is performed in a Lagrangian averaging way along flow paths with a time scale depending on the local flow patterns. The new approach is evaluated by large-eddy simulations of a utility-scale National Renewable Energy Laboratory (NREL)-5MW wind turbine. The results show that the Lagrangian approach of velocity sampling is effective to reduce the spurious numerical oscillations in the modeling results. The good match with the benchmark data indicates that correct free upwind velocity can be obtained with a careful determination of the associated time scale. Also, a piecewise function is proposed to replace the Gaussian function for the force projection process.

中文翻译：

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用于风力涡轮机模拟的具有拉格朗日平均速度采样和分段投影的执行器线模型

提出了一种新方法来对致动器线模型 (ALM) 进行速度采样。与传统的空间平均方法不同，速度采样以拉格朗日平均方式沿流动路径进行，时间尺度取决于局部流动模式。新方法通过公用事业规模的国家可再生能源实验室 (NREL)-5MW 风力涡轮机的大涡模拟进行评估。结果表明，速度采样的拉格朗日方法可以有效地减少建模结果中的虚假数值振荡。与基准数据的良好匹配表明通过仔细确定相关的时间尺度可以获得正确的自由逆风速度。此外，还提出了分段函数来代替力投影过程的高斯函数。