温州滨海平坦地貌近地台风特性实测研究

FIELD MEASUREMENTS OF TYPHOON CHARACTERISTICS NEAR GROUND IN WENZHOU COASTAL FLAT TERRAIN

  • 摘要: 为研究温州滨海平坦地貌近地台风特性,在温州滨海建立了风工程实测基地(塔高10 m),并利用台风"菲特"和"麦德姆"登陆过程中不同高度处风速及风向实测数据,研究了10 m高度范围内的平均风速和风向角、湍流度、阵风因子、湍流积分尺度和功率谱密度等风特性参数。结果表明:离地10 m高度范围内,实测风速剖面系数明显大于该地貌的规范取值,风速平均值和最大值均明显小于国家规范计算值;不同高度处横风向与顺风向湍流度比值随着高度减小而增大,实测湍流度与我国规范取值差异较大;顺风向,湍流积分尺度与平均风速之间的线性规律较好,随着高度增加湍流积分尺度离散性变大,湍流积分尺度的中位数与平均值差别不大,均小于日本规范;顺风向和横风向脉动风速功率谱有一定的变化,峰值频率和峰值都很接近,实测脉动风速的功率谱与Von Karman谱在数值上有一定的差异,但变化趋势基本一致。

     

    Abstract: To gain the typhoon characteristics of wind filed near ground, a 10 m height field measurements wind tower station was set up Wenzhou coastal flat terrain. Series of wind parameters were measured during the passage of typhoon Fitow (2013) and Matmo (2014). Wind field characteristics such as mean wind speed, local wind axis, turbulence intensity, gust factor, turbulence integral scale and power spectral density were obtained for further investigate. The results show that, the wind speed profile index at 10 m height is significantly larger than the standard calculation value on the corresponding geomorphology in China, but the average and maximum wind speed are all much smaller than the standard values. The ratio of lateral turbulence and longitudinal turbulence are highly sensitive at different heights. The ratio increases with the height decreasing and both turbulence are different from the Chinese Standard. As wind speed and height tend to increase, the dispersion of the turbulence integral scale tends to increase linearly, but the median and mean value of turbulence integral scale only change slightly, the values of which are all less than the Japanese standard. With different typhoon, the longitudinal and lateral fluctuating wind power spectrums are different while the peak frequency and peak power are similar. Moreover, with change of magnitude, the value of fluctuating wind power spectrum and Von Karman will change, and the trends in change are similar.

     

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