台风“梅花”近地风剖面变化

Variation of Wind Profiles near Ground During Typhoon "Muifa"

基于10、20、30和40m高度处台风"梅花"影响下的上海浦东地区近地风现场实测数据,主要研究了平均风速、湍流度和阵风因子随高度的变化规律.结果表明,通过公式计算得到的边界层高度随平均风速的增大而增大,平均值为2 063m,远远大于我国规范(GB50009—2001,2002)规定的B类地貌下的边界层高度(350m).当平均风速较大时,大气稳定度参数z/L随平均风速变化较小,基本在区间[-0.1,0.1]内波动,此时大气近似趋于中性.指数率、对数率和Deaves-Harris模型与平均风速实测剖面均吻合较好.参考ASCE7-10中湍流度剖面的表达形式,通过拟合得到了纵向、横向和竖向湍流度随高度变化的经验表达式.另外,对实测阵风因子随高度的变化进行了拟合,拟合结果可以为今后工程设计提供参考.

Wind profiles of typhoon 'Muifa' are analyzed based on the long-term measured data collected respectively at 10,20,30 and 40 meters high from the ground in Pudong New Area of Shanghai.The height of neutral atmospheric boundary layer(ABL) increases with wind speed.The average height of neutral ABL during typhoon 'Muifa' is 2 063 m by calculation,which greatly exceeds the gradient height(350 m) recommended by Chinese National Load Code(GB50009 —2001,2002) for open terrain.The stability parameter z/L is almost within [-0.1,0.1] when the wind speed becomes high,which means near-neutral flow.Measured mean wind speed profile agrees well with the power law,the log law and Deaves-Harris ABL model.Based on the expression form in ASCE7-10,the fitting equations of turbulence intensity profiles in longitudinal,lateral and vertical directions are presented.Finally,the formulas for gust factors are also derived using curve-fitting technique,which can provide reference for engineering designing.