Abstract The diurnal variation of atmospheric conditions over land has a significant effect on the wind and temperature distributions which greatly influence the generation and propagation of wind turbine aerodynamic sound. In this paper, a fully consistent unsteady approach is used to study wind turbine noise such that large eddy simulation with a rotational actuator disk wind turbine model is used to model the wind and temperature around a mega-watt scale wind turbine over a diurnal cycle, and time dependent flow and temperature fields are used as input to the coupled wind turbine noise generation-propagation model. Computations are carried out for four different 10 min datasets selected at certain periods of a day for a same hub height wind speed. It is observed that the time dependent as well as the time averaged sound pressure levels in near field do not show large variations during the day. However, as we move away from the turbine, the propagation effects take over and downwind of the turbine the night time levels exceed the day time levels (at 3600 m the averaged difference reaches 6.5 dBA).

中文翻译：

---

风力涡轮机噪声在昼夜循环中的变化

摘要 陆地大气条件的日变化对风力和温度分布有显着影响，对风力机气动声的产生和传播有很大影响。在本文中，使用完全一致的非定常方法来研究风力涡轮机噪声，例如使用旋转致动器盘风力涡轮机模型的大涡模拟来模拟昼夜循环中兆瓦级风力涡轮机周围的风和温度，和时间相关的流场和温度场被用作耦合风力涡轮机噪声生成-传播模型的输入。针对同一轮毂高度风速，在一天的某些时段选择四个不同的 10 分钟数据集进行计算。据观察，近场中的时间相关声压级以及时间平均声压级在白天没有显示出大的变化。然而，当我们远离涡轮机时，传播效应接管了涡轮机的下风向，夜间水平超过了白天水平（在 3600 米处，平均差异达到 6.5 dBA）。