Chapter 10 Probabilistic Characteristicoffluctuating wind10.1月脉动风的概率分布10.1Probabilistic distribution of fluctuating wind35040011350中国公路桥梁中国公路桥梁1300抗风设计规范抗风设计规范1中国建筑结构对数律，B=1.8300荷载规范中国建筑结构250日本建筑规范荷载规苑日本建筑规范250200三E200NN1501501001005050市10106868101214161820222426283022101214161820B类地貌I（%)C类地貌I（%
Chapter 10 Probabilistic Characteristic of fluctuating wind 10.1 脉动风的概率分布 10.1 Probabilistic distribution of fluctuating wind
10.1脉动风的概率分布10.1 Probabilisticdistribution of fluctuatingwind流积分长度（Turbulenceintegrallength）通过某一点气流中的速度脉动可以认为是由平均风所运输的一些理想涡旋叠加而引起的，若定义涡旋的波长就是涡旋大小的量度，紊流积分尺度则是气流中流涡旋平均尺寸的量度。The velocity fluctuation passing through a point canbe recognized as the Superposition of the ideal vortextransported by mean wind. If the wavelength isdefined as the measurement of vertex size,Turbulence integral length is the measurement ofaverage size of the turbulent vortex in the airflow
湍流积分长度（Turbulence integral length） 通过某一点气流中的速度脉动可以认为是由平均风所运输 的一些理想涡旋叠加而引起的，若定义涡旋的波长就是涡旋 大小的量度，紊流积分尺度则是气流中湍流涡旋平均尺寸的 量度。 The velocity fluctuation passing through a point can be recognized as the Superposition of the ideal vortex transported by mean wind. If the wavelength is defined as the measurement of vertex size, Turbulence integral length is the measurement of average size of the turbulent vortex in the airflow. 10.1 脉动风的概率分布 10.1 Probabilistic distribution of fluctuating wind
10.1脉动风的概率分布10.1 Probabilistic distribution of fluctuatingwind流积分长度从数学上可定义为Themathematicaldefinitionofturbulence integral can be defined as follow:1ww(x)dx(y)dy2(z)dzCL(z)dz(x)dxL(y)dyLm(z)dz(x)dx(y)dy2函数C分别表示两个脉动风速的互协方差函数FunctionCrespectivelyrepresentscovariance functionsoftwo pieces of fluctuating wind.如果互协方差函数是相隔距离的快速递减函数，则流积分长度很小，紊流影响也很小。反之如果互协方差函数随相隔距离的增大递减很慢，则瑞流积分长度很大，紊流的影响也大。Ifthe covariance function is a fast decreasingfunction of the distance,thenthe interval of turbulenceintegral is small, correspondinglythe effect ofturbulenceissmall.Conversely,Ifthe covariancefunction decreases slowlywith distance, the interval of turbulence integral is large, the effect ofturbulenceisalsolarge
函数C分别表示两个脉动风速的互协方差函数 Function C respectively represents covariance functions of two pieces of fluctuating wind. 如果互协方差函数是相隔距离的快速递减函数，则湍流积分长度很小，紊流影响也很 小。反之如果互协方差函数随相隔距离的增大递减很慢，则湍流积分长度很大，紊流 的影响也大。 If the covariance function is a fast decreasing function of the distance, then the interval of turbulence integral is small, correspondingly the effect of turbulence is small. Conversely, If the covariance function decreases slowly with distance, the interval of turbulence integral is large, the effect of turbulence is also large. 湍流积分长度从数学上可定义为 The mathematical definition of turbulence integral can be defined as follow: 10.1 脉动风的概率分布 10.1 Probabilistic distribution of fluctuating wind