基于台风“梅花”的近地层脉动风速功率谱及相干性研究

Field measurements for the power spectral densities and spatial coherence of fluctuating wind speed near ground during typhoon ‘Muifa’

  • 摘要: 基于10m、20m和40m高度处台风“梅花”影响下的上海浦东地区近地风实测数据,分析了脉动风速自功率谱、互功率谱及相干特性,并基于Kaimal互功率谱提出了纵向与竖向以及纵向与横向分量之间脉动风速互功率谱模型。结果表明:纵向脉动风速功率谱与Von Karman经验谱吻合较好,而横向和竖向脉动风速功率谱与Von Karman经验谱在高频段有所偏差;实测脉动风速互功率谱与本文提出的Kaimal修正谱符合较好;纵向、横向和竖向风速脉动分量相干函数的指数衰减系数均值分别为10.71、7.43和8.63,并且发现实测两点的脉动风速空间相干系数符合Davenport经验公式的计算结果。

     

    Abstract: The wind characteristics of typhoon ‘Muifa’ such as power spectrum, cross power spectrum and coherence function are analyzed on the basis of long time measured data which is recorded respectively at the height of 10m, 20m and 40m above the ground in Pudong Shanghai, and two kinds of new cross power spectrum models are proposed based on Kaimal model. It is shown that longitudinal fluctuating wind power spectrum roughly fit with Von Karman spectrum, but there has deviation in high frequency band between lateral and vertical fluctuating wind power spectrum and Von Karman spectrum. By comparison, it can be found that measured fluctuating wind cross power spectrum is in agreement with modified Kaimal model. Averaged decay factor of 10min wind speed samples in longitudinal, lateral and vertical directions are 10.71, 7.43 and 8.63, respectively. In addition, the measured spatial coherence is consistent with Davenport’s empirical formula.

     

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