开缝式柔性膜结构对5∶1矩形柱体气动力的影响  

Effects of open-slit flexible film structure on aerodynamics of a 5∶1 rectangular cylinder

作　　者：尹亚鹏 王汉封[1,2] 李欢[1,2] 何旭辉[1,2] 黄致睿[1] YIN Yapeng;WANG Hanfeng;LI Huan;HE Xuhui;HUANG Zhirui(School of Civil Engineering,Central South University,Changsha 410075,China;National Engineering Research Center for High-speed Railway Construction Technology,Central South University,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]中南大学高速铁路建造技术国家工程研究中心,湖南长沙410075

出　　处：《铁道科学与工程学报》2022年第11期3326-3334,共9页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52078505)。

摘　　要：针对刚性风屏障会增加桥梁结构阻力和扭矩的问题,基于仿生学原理,设计一种开缝式柔性膜结构。采用测压试验,通过改变攻角等参数,系统地研究开缝式柔性膜结构对5∶1矩形柱体风压分布和气动力的影响,为推广开缝式柔性膜结构在扁平箱梁的应用提供依据。研究结果表明:试验模型的水平对称性和流动二维性比较好,测压试验结果与已有试验结果吻合良好,可以用来分析柔性膜结构对矩形柱体气动力的影响。开缝式柔性膜结构不同位置处的风压系数有区别,其拍动引起的旋涡,加剧了外部气流同柱体表面气流的动量交换。无柔性膜结构时,矩形柱体各截面有较强的展向相关性,在攻角0°~10°范围,柱体表面具有大尺度展向旋涡脱落。柔性膜结构削弱了大尺度展向旋涡,降低了升力系数的展向相关性,是三分力系数减小的重要原因。单独一片柔性膜结构的影响区域有限,沿流向脉动风压迅速衰减,对两片膜结构之间的缝隙处影响较弱。开缝式柔性膜结构对矩形柱体的气动力有较强的影响,在4°攻角下,平均阻力系数最大下降11.8%,平均升力系数最大下降34.5%,平均扭矩系数最大下降60.7%;脉动阻力系数最大下降66.4%,脉动升力系数最大下降68.2%,脉动扭矩系数最大下降55.0%。Based on the bionic principle, an open-slit flexible film structure was designed to systematically study the effects of open-slit flexible film structure on the wind pressure distribution and aerodynamics of a 5: 1 rectangular cylinder by changing the angle of attack, in order to provide a basis for promoting the application of open-slit flexible film structure in flat box girders. The results of the study show that the horizontal symmetry and flow two-dimensionality of the experimental model are good. The results of the pressure test are in good agreement with the existing test results, and can be used to analyze the effect of the flexible film structure on the aerodynamic force of the rectangular cylinder.The wind pressure coefficients at different positions of the open-slit flexible film are different, and the vortex caused by its flapping intensifies the momentum exchange between the external airflow and the airflow on the surface of the cylinder. When there is no flexible film structure, each section of rectangular cylinder has a strong spanwise correlation, and in the range of angle of attack 0°~10°, the surface of the cylinder has a large scale spanwise vortex shedding.The flexible film structure weakens the large scale spanwise vortex and reduces the spanwise correlation of the lift force coefficient, which is an important reason for the reduction of the three-part force coefficient.The influence area of a single flexible film structure is finite, the fluctuation of wind pressure along the streamwise decays rapidly, and the influence on the gap between the two film structures is weak. The open-slit flexible film has a strong influence on the aerodynamics of the rectangular cylinder, with a maximum decrease of 11.8% in the average drag coefficient, 34.5% in the average lift coefficient, 60.7% in the average moment coefficient, 66.4% in the fluctuating drag coefficient, 68.2% in the fluctuating lift coefficient, and 55.0% in the fluctuating moment coefficient.

关 键 词：开缝式柔性膜结构 矩形柱体 气动力 

分 类 号：U238[交通运输工程—道路与铁道工程]