台风“苏迪罗”行进过程中沿海近地实测风场特性研究

Coastal near ground actually measured wind field characteristicsin typhoon “Soudelor” moving process

基于厦门大嶝岛台风观测点阵列布置风速仪的现场实测,选取了1513号台风“苏迪罗”在四个不同时间段的风速风向数据,对台风行进过程中的沿海近地风场特性进行了详细分析,得到了台风中心距离观测点400 km、250 km、150 km和120 km时的沿海近地平均风速风向、风剖面、阵风因子、湍流度、湍流积分尺度和功率谱密度函数等参数,研究了各种参数同台风中心距和观测高度之间的关系,结果表明:在台风行进过程中,观测点所测风速的平均风速剖面满足对数律规律,粗糙长度z_0约为4.0 m。阵风因子和湍流度变化较为平缓,二者呈线性变化关系。三个方向上的湍流度比值约为1∶0.8∶0.45,湍流积分尺度离散性大,顺、横风向的功率谱密度函数符合von Karman谱的形式,但竖直方向不符合。该结果对深入了解台风在行进中对固定观测点的影响以及提高沿海工程结构的抗风安全性具有实际意义。

Here,based on on-site measurement of anemometers arranged on typhoon observation point array at Dadeng island in Xiamen city,wind speed and wind direction data of Typhoon“Soudelor”within 4 different time periods were selected.Characteristics of coastal near ground wind field during typhoon moving were analyzed in detail.Parameters of average wind speed and direction,wind profile,gust factor,turbulence intensity,turbulence integral scale and power spectral density function of coastal near ground were obtained when typhoon center was 400 km,250 km,150 km and 120 km away from observation points.Relations among various parameters,typhoon center distance and observation height were studied.The results showed that in process of typhoon moving,average wind speed profile of wind speeds measured at observation points follows a logarithmic law,and the rough length z 0 is about 4.0 m;changes in gust factor and turbulence intensity are relatively gentle,and there is a linear relation between the two;the ratio of turbulence intensities in 3 directions is about 1∶0.8∶0.45,and turbulence integral scale has large discreteness;power spectral density functions in downwind and crosswind directions conform to the form of von Karman spectrum,but that in vertical direction does not conform to;the study results can have practical significance for deeply understanding effects of typhoons on fixed observation points during their movement and improving the anti-wind safety of coastal engineering structures.