城市地貌高空台风特性及湍流积分尺度的研究

Study on typhoon characteristics at high urban landform altitude and turbulence integral length scale

基于2014年第10号台风"麦德姆"在城市地貌的高空实测风场资料,共选取五个时距(30s、1min、5min、10min和20min)进行分析,得到平均风速、风向、湍流度、阵风因子和脉动风速谱等强风特性;然后采用两种基于Taylor假定的方法来计算湍流积分尺度,分别从平均风速、湍流度和阵风因子等要素来探讨不同时距对湍流积分尺度的影响。分析结果表明:当平均时距为5min时,计算得到的平均风速较大、湍流度和阵风因子均较小,对应的方差与变异系数也较小,根据其计算得到的湍流积分尺度分布最为集中,其中又以自相关函数积分法得到的方差最小,最为合理。

Based on the actually measured wind field materials about No.10 Typhoon,namely Matmo,from high urban-landform altitude in 2014,the data were analyzed in five time intervals(30 s,1 min,5 min,10 min and 20 min respectively),and strong wind characteristics were obtained with respect to the averaged wind speed,the wind direction,the turbulence intensity,the gust factor,and the fluctuating wind spectrum.The turbulence integral scale was then calculated with two methods based on Taylor assumption to investigate the effects of time intervals on the turbulence integral scale regarding the averaged wind speed,the turbulence intensity,and the gust factor.The results show that the averaged wind speed is the highest when the average time interval is 5 min.However,the turbulence intensity,the wind gust factor,and the corresponding variances and coefficients of variation are the smallest.These results are reasonable due to the densest calculated distributions of turbulence integral scale and the lowest variance gained by self-correlation function integral method.