方形结构风荷载Jensen数效应研究  

Study on Jensen number effect of wind load on square structure

作　　者：白桦[1] 叶茂 杨世全 刘健新[1] BAI Hua;YE Mao;YANG Shiquan;LIU Jianxin(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China)

机构地区：[1]长安大学公路学院,陕西西安710064

出　　处：《建筑科学与工程学报》2023年第2期105-115,共11页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(51978077);陕西省自然科学基础研究计划项目(2023-JC-YB-408);重庆市在渝院士牵头科技创新引导专项(2022YSZX-JSX0003CSTB)。

摘　　要：为了解试验模拟的地表粗糙度偏差对方形结构风荷载的影响,在风洞中模拟不同缩尺比的A、B两类粗糙度指数风场,研究Jensen数分别为1200、6000时结构风荷载的Jensen数效应。结果表明:Jensen数变化对平均风荷载影响很小,对脉动风荷载影响较大;Jensen数由6000减小到1200时,顺风向、横风向、扭矩脉动风荷载增大幅度约为200%~250%;Jensen数减小会使风荷载功率谱低频段能量呈小幅增大趋势,高频段能量呈小幅减小趋势;当来流与方形结构的直线边存在一定夹角时,Jensen数变化对各类型风荷载相关性影响变小;Jensen数增大会使各层间顺风向、横风向与扭矩风荷载相关性减小;Jensen数由1200增大为6000时,对扭矩风荷载相关性影响最大,降幅为63%,横风向风荷载相关性最大降幅为40%,顺风向风荷载相关性最大降幅为15%;增大Jensen数会使顺风向风荷载相干函数与Davenport指数衰减形式吻合的频率范围增大,高频部分的竖向相干函数减小;横风向风荷载与扭矩风荷载竖向相干函数更符合Davenport指数衰减形式。In order to understand the effect of the deviation of surface roughness on square structure wind load,two kinds of roughness index wind fields of A and B with different scale ratios were simulated in wind tunnel,and the Jensen number effect on the structural wind load when the Jensen number was 1200 and 6000 respectively was studied.The results show that the variation of the Jensen number has little influence on the mean wind load,while it has a greater influence on the fluctuating wind load.When the Jensen number is reduced from 6000 to 1200,the increase range of along-wind,cross-wind and torsional wind load is 200%-250%.With the decrease of the Jensen number,the energy of the wind load power spectrum increases slightly in low frequency,and decreases slightly in high frequency.The influence of the change of the Jensen number on the various types of wind load is relatively small,when there is an intersection angle between the flow direction and the straight edge of the square structure.The increase of Jensen number will reduce the correlation between along-wind direction,cross-wind direction and torsional wind load.The increase of the Jensen number from 1200 to 6000 imposes great effects on torsional wind load,which has a decrease of 63%,while the maximum decrease in across-wind load correlation is 40%and the maximum decrease in along-wind load is 15%.With the increase of the Jensen number,the frequency range of the along-wind load coherence function with the Davenport exponential attenuation increases,while vertical coherence function decreases in high frequency part.The vertical coherence function of cross-wind load and torsional wind load is more consistent with the Davenport exponential attenuation form.

关 键 词：方形结构 风洞试验 Jensen数 风荷载 相关性 

分 类 号：TU317.1[建筑科学—结构工程]