下击暴流风特性及其对高耸桅杆动力作用的实测分析

Observational study of wind characteristics of thunderstorm and dynamic effects on high-rise masts

为了研究下击暴流的风场特性及其对高耸结构的动力作用,依据高度356 m的深圳气象观测梯度塔获取了下击暴流风记录及其加速度响应。分析了雷暴风的平均风速、湍流度及脉动风功率谱特性,并进一步研究了下击暴流作用下梯度塔的动力响应特征。分析结果表明:下击暴流风速剖面形态具有时变性,且不同时刻的风速剖面与目前常用的经验剖面均有一定的差异;雷暴过程湍流强度随高度变化规律性不显著,其脉动风功率谱与von Karman谱和Solari谱较为吻合;下击暴流作用下梯度塔的最大风振响应出现在雷暴过程的上升段而非最大风速时刻,其响应和顺风向风振系数均随高度增加而增大;风振过程中梯度塔多模态参与特征明显,且纤绳振动的影响不可忽略。

To study the wind characteristics of thunderstorms and their dynamic effects on high-rise masts, the downburst wind records and the acceleration response were obtained on the 356 m Shenzhen Meteorological Gradient Tower(SZMGT). The characteristics of mean wind, turbulence, and wind spectrum for downbursts were analyzed, and the dynamic response of SZMGT to downburst outflows was further investigated. It is observed that the vertical profiles of thunderstorm change with time and the profiles at different moments are somewhat different from the current common empirical profiles. The variation of turbulence intensity with height during thunderstorms is not significant in regularity, and the wind spectrum is more consistent with the von Karman spectrum and Solari spectrum. The maximum dynamic response of SZMGT under the action of thunderstorm outflow appears in the ramp-up stage instead of the peak stage of thunderstorms, and the dynamic response as well as the along-wind vibration coefficient of the SZMGT both increase with height. The multimodal participation for the response of SZMGT is very obvious, and the effect of rope vibration is not negligible.