中央格栅抑制分离式双箱梁涡振的机理研究  

Mechanism of Suppressing Vortex-Induced Vibration of Twin-Box Girder Using Central Grids

作　　者：李志国[1,2] 周强 马存明 廖海黎[1,2] 

机构地区：[1]西南交通大学风工程试验研究中心,四川成都610031 [2]风工程四川省重点实验室,四川成都610031

出　　处：《桥梁建设》2018年第1期19-24,共6页Bridge Construction

基　　金：国家自然科学基金项目(51378442;51708462);中央高校基本科研业务费理工类科技创新项目(2682016CX006)~~

摘　　要：为研究分离式双箱梁涡振的原因以及中央格栅对其涡振的抑振影响,以拟建中的伶仃洋航道桥主桥(主跨1 660m的分离式双箱梁悬索桥)为背景,基于计算流体动力学,运用延迟分离涡湍流模型,采用结构化网格体系,对均匀流下有、无格栅2种加劲梁断面周围的流场进行数值模拟研究,并分析了2种断面周围的流场结构以及断面上的气动力特性。结果表明:流体经过上游断面时,会在分离式双箱梁的中央开槽处形成大尺度、交替脱落的旋涡,然后与下游断面发生碰撞,并产生幅值较大的升力,从而导致涡振发生;当设置中央格栅后,分离式双箱梁开槽处的大尺度旋涡被打碎,强度减弱,尺度减小,产生的断面升力幅值也明显减小,从而有效抑制了涡振的发生。To investigate the causes leading to the vortex-induced vibration （VIV） of the twin- box girder and the influences of the central grids installed on the girder on the suppression of the VIV, the main bridge （a twin-box girder suspension bridge with the main span of 1 660 m） of the Lingdingyang Ship Channel Bridge to be built was cited as an example. The flow fields around the 2 types of the sections of the stiffening girder of the bridge with or without the grids under the uni-form flow were numerically simulated and studied, using the delayed detached eddy simulation model and the structurized grid system, on the basis of the computational fluid dynamics and the flow field structures around the 2 sections and the aerodynamic characteristics on the sections were analyzed as well. The results reveal that when the flow passes the sections on the upstream side, the flow firstly forms the large scale and alternatively shedding vortex at the central slotting of the twin-box girder, then pounds on the sections on the downstream side, produces the lift of great range values and finally results in the occurrence of the VIV. When the central grids are installed, the large scale vortex at the central slotting is broken down, the intensity of the vortex is weak-ened and the scale is reduced. The range values of the produced lift in the sections also become sig-nificantly weakened and consequently, the occurrence of the VIV is effectively suppressed.

关 键 词：悬索桥 分离式双箱梁 中央格栅 涡激振动 计算流体动力学 气动力特性 

分 类 号：U448.25[建筑科学—桥梁与隧道工程] U441.3[交通运输工程—道路与铁道工程]