第章脉动风的概率特性Chapter 1o Probabilistic Characteristic offluctuating wind10.1脉动风的概率分布10.1 Probabilistic distribution of fluctuating wind脉动风反映了大气边界层中自然风的瑞流特性Fluctuatingwindreflectsthefluctuatingcharacteristicsofnatural windturbulence in the atmospheric boundary layer风速的脉动特性对工程结构的作用十分重要Thefluctuationcharacteristic of wind is very important to engineeringstructures刚性结构要受到脉动风速所产生的阵风荷载Rigidstructures are subject to gust loading generated byfluctuating wind柔性结构在脉动风速作用下会发生动力响应Flexiblestructuresproducedynamicresponseunderfluctuatingwind
第十章 脉动风的概率特性 Chapter 10 Probabilistic Characteristic of fluctuating wind 10.1 脉动风的概率分布 10.1 Probabilistic distribution of fluctuating wind 脉动风反映了大气边界层中自然风的湍流特性 Fluctuating wind reflects the fluctuating characteristics of natural wind turbulence in the atmospheric boundary layer 风速的脉动特性对工程结构的作用十分重要 The fluctuation characteristic of wind is very important to engineering structures 刚性结构要受到脉动风速所产生的阵风荷载 Rigid structures are subject to gust loading generated by fluctuating wind 柔性结构在脉动风速作用下会发生动力响应 Flexible structures produce dynamic response under fluctuating wind
Chapter 10 Probabilistic Characteristic offluctuating wind10.1Probabilistic distribution of fluctuating wind柔性结构的空气动力特征的参数可以分为能量特征参数和空间特征参数Theaerodynamiccharacteristicparametersofflexiblestructures can be described by energy characteristicparameters and spatial characteristic parameters能量参数：流度、脉动风功率谱Energy parameters : turbulence intensity,wind power spectrum■空间参数：流积分尺寸、空间相关性。Space parameters : turbulence integral dimension, spatialcorrelation
Chapter 10 Probabilistic Characteristic of fluctuating wind 10.1 Probabilistic distribution of fluctuating wind 柔性结构的空气动力特征的参数可以分为能量特征参数和空间 特征参数 The aerodynamic characteristic parameters of flexible structures can be described by energy characteristic parameters and spatial characteristic parameters. 能量参数：湍流度、脉动风功率谱 Energy parameters : turbulence intensity, wind power spectrum 空间参数：湍流积分尺寸、空间相关性。 Space parameters : turbulence integral dimension, spatial correlation
10.1 Probabilistic distribution of fluctuatingwind对风速记录的分析表明，如果忽略初始阶段的严重非平稳区域，脉动风十分接近于平稳随机过程，它的概率密度很接近于正态分布Wind speed record analysis shows that if the seriousnon-stationary parts is ignored in the initial phase , thefluctuating wind is very close to stationary randomprocess, the probability distribution is very close tonormal distribution, =[ ()-] a-{u(0)al]纵向longiudinal横向voa宁lateral平时工竖直向Tw'alvertical
10.1 Probabilistic distribution of fluctuating wind 对风速记录的分析表明，如果忽略初始阶段的严重非平稳区域 ，脉动风十分接近于平稳随机过程，它的概率密度很接近于正 态分布 Wind speed record analysis shows that if the serious non-stationary parts is ignored in the initial phase，the fluctuating wind is very close to stationary random process, the probability distribution is very close to normal distribution
10.1脉动风的概率分布10.1 Probabilisticdistributionof fluctuatingwind瑞流度（Turbulenceintensity）描述脉动风强度的重要参数，是衡量脉动风能量大小的标志TheFactorthat descriptsthe strengthoffluctuatingwind.It isacriteria for measuring the energy of fluctuating windu==w=为脉动风速的根方差；为平均风速oisthestandarddeviationoffluctuatingwindanduisthemeanwindspeedAU 1996Tested无量纲的瑞流度随高度增加而减小6The turbulence intensitywithout dimension decreases50withincreasingaltitude40其具体分布规律与地貌有关Thespecificdistributionruleisrelatedtothelandforms36靠近地面一般可达20%以上。20The intensity can exceed 20 percent close to the groundA10AAA01015202530lu/%
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一些国家的规范（如日本、澳大利亚）中给出了不同地貌条件下纵向脉动风流度随高度的变化Thecodes inothercountries such as JapanandAustraliagivesthe longitudinalfluctuating wind turbulence under differentgeomorphologicalconditions varying with height我国《建筑物荷载规范》并没有明确规定，但隐含采用下式ChineseLoad Code for the design of building has no specificregulations but implicitly recommends adopting the followingformulaIu= 0. 1(z/ Hc)-α-0.05《公路桥梁抗风设计指南》给出了建议值Wind-resistentDesign SpecificationforHighway Bridgesgivesthe recommendvaluesI, = 0.88lu Iw = 0.50u
10.1 脉动风的概率分布 10.1 Probabilistic distribution of fluctuating wind