台风“海马”登陆中心近地风场特性实测研究

Field measurement research of near ground wind field characteristics at landing center during typhoon ’Haima’

为研究台风“海马”的近地面风场特性,在位于其登陆中心的观测塔离地高度位置20 m和10 m处安装了测风装置,分析了平均风速和风向、湍流强度、阵风因子、湍流积分尺度以及脉动风速功率谱密度等风场特征参数。结果表明：台风登陆前后的中心风速时程呈M形变化,平均风向角发生反向改变,不同高度的平均风速和风向角有所差异;湍流强度和阵风因子均在登陆时刻最大,20 m和10 m高度的湍流强度均值分别为0. 26和0. 31、阵风因子分别为1. 73和1. 89,均随高度和风速的增大而递减,其值较中国、美国和日本建筑规范的对应地貌规定值小,湍流强度和阵风因子关系的拟合结果相较经验公式偏大;台风经过期间的20 m和10 m高度处湍流积分尺度均值分别为136 m和85 m,随高度和风速的增大而增大,其随高度的变化趋势比美国和日本建筑规范对应地貌的结果更加明显;脉动风速功率谱密度随着风速和积分尺度的增大逐渐满足Kolmogrove-2/3律,实测结果与von Karman谱吻合较好。

In order to study the near ground wind field characteristics of typhoon ＇ Haima＇ , wind measuring devices were installed in a monitoring tower at the heights of 20 m and 10 m from the tower foundation respectively. The monitoring tower was located at the typhoon＇ s landing center. Some characteristic parameters of wind field were analyzed, such as mean wind speed and direction, turbulence intensity, gust factor, integral scale of turbulence and power spectrum density of fluctuating wind speed. Results show that ： before and after typhoon＇ s landing, the central wind speed varies with M shape, the mean wind direction is reversed and wind speed and direction are different at different heights ; the measured turbulence intensity and gust factor are the largest at the landing time ; the mean values of the turbulence intensity at 20 m and 10 m heights during typhoon are respectively 0. 26 and 0. 31 and the corresponding values of gust factor are respectively 1.73 and 1.89. The values are reduced with the increase of height and wind speed, and are smaller than the values prescribed in the Chinese, American and Japanese building codes. The fitted relationship of turbulence intensity and gust factor is larger than empirical formulas; the mean values of turbulence integral scale at 20 m and 10 m heights are respectively 136 m and 85 m, and are increased following height and wind speed＇ s increase. The changing tendency of turbulence integral scale following height＇ s increase is more obvious than the corresponding results of American and Japanese building codes; fluctuating wind spectrums gradually conform to the Kolmogrove-2/3 law with the increase of wind speed and integral scale. The measured spectrums are in good agreement with the von Karman spectrum during typhoon ＇ Haima＇.