On wind turbine loads during the evening transition period
On wind turbine loads during the evening transition period
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DOI：
10.1002/we.2355
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发表时间：
2019-10
期刊：
影响因子：
4.1
通讯作者：
Nanjun Lu;S. Basu;L. Manuel
中科院分区：
文献类型：
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作者：
Nanjun Lu;S. Basu;L. Manuel
在日循环中，下午晚些时候先于夜间稳定边界层的发展。这个“傍晚过渡”（ET）时期通常是能源需求达到峰值的时候。这段时间也对应于一天中的时间，这是下午晚些时候下击暴流的前兆，这是一个单独的兴趣主题。为了捕捉大气边界层（ABL）风场的物理特性，特别是切变和湍流的相互作用，随机模拟方法，虽然更容易处理，是不合适的。另一方面，大涡模拟（LES）可用于生成高分辨率ABL湍流场。我们提出了一套理想化的LES四维流场，这些流场定义了一个数据库，代表大尺度大气条件（以相关的地转风为特征）和表面边界条件（以表面热通量为特征）的不同组合。我们的目标是评估ET期间风力涡轮机的性能。因此，我们对涡轮机尺度风场变量进行了统计分析。然后，我们采用这些LES的流入风场的数据库中的气动弹性模拟的5兆瓦风力涡轮机。我们讨论了涡轮机负荷如何随着ET周期的变化而变化。我们还讨论了不同ABL条件下转子和塔架上的最大载荷和疲劳载荷。研究结果表明，在ET期间，盛行的地转风速影响的平均值和方差的纵向风很大，从而有显着的影响，除了偏航力矩是不太敏感的均匀和对称的来流的所有负载。另一方面，表面热通量水平对垂直湍流和风切变的影响更大，因此，仅影响最大叶片挥舞弯曲和塔架前后弯曲载荷。
The late afternoon hours in the diurnal cycle precede the development of the nocturnal stable boundary layer. This “evening transition” (ET) period is often when energy demand peaks. This period also corresponds to the time of day that is a precursor to late‐afternoon downbursts, a subject of separate interest. To capture physical characteristics of wind fields in the atmospheric boundary layer (ABL) during this ET period, particularly the interplay of shear and turbulence, stochastic simulation approaches, although more tractable, are not suitable. Large‐eddy simulation (LES), on the other hand, may be used to generate high‐resolution ABL turbulent flow fields. We present a suite of idealized LES four‐dimensional flow fields that define a database representing different combinations of large‐scale atmospheric conditions (characterized by associated geostrophic winds) and surface boundary conditions (characterized by surface heat fluxes). Our objective is to evaluate the performance of wind turbines during the ET period. Accordingly, we conduct a statistical analysis of turbine‐scale wind field variables. We then employ the database of these LES‐based inflow wind fields in aeroelastic simulations of a 5‐MW wind turbine. We discuss how turbine loads change as the ET period evolves. We also discuss maximum and fatigue loads on the rotor and tower resulting from different ABL conditions. Results of this study suggest that, during the ET period, the prevailing geostrophic wind speed affects the mean and variance of longitudinal winds greatly and thus has significant influence on all loads except the yaw moment which is less sensitive to uniform and symmetric incoming flow. On the other hand, surface heat flux levels affect vertical turbulence and wind shear more and, as a result, only affect maximum blade flapwise bending and tower fore‐aft bending loads.