稳态雷暴冲击风作用下典型矩形梁断面风压特性数值模拟研究  

Numerical simulation of wind pressure characteristics of typical rectangular beam section under steady-state thunderstorm downburst wind

作　　者：胡朋[1] 陈飞 韩艳[1] 陈婉婷 李春光[1] 胡广德 HU Peng;CHEN Fei;HAN Yan;CHEN Wanting;LI Chunguang;HU Guangde(School of Civil Engineering,Changsha University of Science&Technology,Changsha 410114,China;Henan Communications Planning&Design Institute Co.,Ltd.,Zhengzhou 450015,China)

机构地区：[1]长沙理工大学土木工程学院,长沙410114 [2]河南省交通规划设计研究院股份有限公司,郑州450015

出　　处：《振动与冲击》2024年第21期116-127,共12页Journal of Vibration and Shock

基　　金：国家自然科学基金项目(52178451,51878080,52178452);湖南省自然科学基金项目(2024JJ2002);长沙理工大学研究生科研创新项目(CXCLY2022049)。

摘　　要：为研究稳态雷暴冲击风作用下矩形梁断面的风压特性,采用大涡模拟方法,对不同径向位置下2∶1矩形梁断面的绕流场进行数值模拟,并将数值模拟值与风洞试验值进行对比。在此基础上,对矩形梁断面的绕流场和风压分布特性进行了分析,并对矩形梁断面风压功率谱及相关性进行了研究。研究结果表明:在r=0.6D jet(发展阶段)、r=1.8 D jet(成熟阶段)和r=4.0D jet(消散阶段)三个典型工况下,矩形梁表面风压系数基本沿着中心轴对称,且矩形梁距离射流中心越远,其风压系数绝对值越小。其中,迎风面风压系数均为正值,下表面及背风面风压系数均为负值,而上表面的风压系数随不同径向距离而变化显著。在r=1.8D jet位置处,气流在下表面后端发生一定程度的再附,使下表面后端的压力有所增大;在r=4.0D jet位置处,气流在上表面前端发生分离导致前端负压进一步变大。迎风面区域的旋涡已经形成稳定结构,各测点的脉动风压能量基本保持稳定,背风面的上拐角处附近能量达到最大,而上表面和下表面的前拐角处能量较低。矩形梁断面同面测点风压系数均为正相关,且风压相关性随着测点间距的增加而减小;迎风面测点脉动风压相干性较强,相干函数值在0.9左右;而上表面和背风面测点的脉动风压分别在0.05 Hz附近以及在频率低于0.2 Hz时具有很强的相干性。在气动导纳函数方面,传统的Sears函数值在雷暴冲击风环境下将不再适用。To study wind pressure characteristics of rectangular beam section under steady-state thunderstorm downburst wind,the large eddy simulation(LES)method was used to numerically simulate the flow field around a 2∶1 rectangular beam section at different radial positions,numerical simulation values were compared with wind tunnel test values.Then,flow field and wind pressure distribution characteristics of rectangular beam section were analyzed,wind pressure power spectrum and correlation of rectangular beam section were studied.The study results showed that under 3 typical operating conditions of r=0.6D jet in development stage,r=1.8D jet in mature stage and r=4.0D jet in dissipation stage,surface wind pressure coefficients of rectangular beam are basically symmetric along center axis,the farther the rectangular beam is from jet center,the smaller the absolute values of its wind pressure coefficients;for the 3 conditions,wind pressure coefficients on windward surface are all positive,while wind pressure coefficients on lower surface and leeward surface are negative;wind pressure coefficients on upper surface vary significantly with different radial distances;at the position of r=1.8D jet,airflow undergoes a certain degree of reattachment at rear end of lower surface to cause increase in pressure at rear end of lower surface;at the position of r=4.0D jet,airflow separates at front end of upper surface to cause further increase in negative pressure at front end;vortexes in windward surface area have formed a stable structure,fluctuating wind pressure energy at each measuring point remains basically stable;energy near upper corner of leeward surface reaches the maximum,while energy at front corner of upper surface or lower surface is lower;wind pressure coefficients of the same plane measurement points of rectangular beam section are all positively correlated,and wind pressure correlation decreases with increase in measurement point spacing;fluctuating wind pressure coherence for windward surface measurement points is

关 键 词：雷暴冲击风 矩形梁 大涡模拟 风压系数 脉动风压 

分 类 号：TH312.1[机械工程—机械制造及自动化]