大跨度缆索承重桥并列索尾流激振研究  

On wake-induced vibration of parallel cables in cable-supported bridges

作　　者：杜晓庆[1] 蒋本建 代钦[2] 王国砚[3] 孙雅慧[1] 

机构地区：[1]上海大学土木工程系,上海200072 [2]上海大学上海市应用数学和力学研究所,上海200072 [3]同济大学航空航天与力学学院,上海200092

出　　处：《振动工程学报》2016年第5期842-850,共9页Journal of Vibration Engineering

基　　金：上海市自然科学基金资助项目(14ZR1416000);上海市教委科研创新项目(14YZ004);国家自然科学基金资助项目(51578330)

摘　　要：近距离并列索（并列吊索和并列斜拉索）在大跨度缆索承重桥中应用广泛,下游索常会发生尾流致涡激共振、尾流驰振和尾流颤振等尾流激振。以间距为4 D（D为圆柱直径）的串列和错列双圆柱的尾流致涡激共振和尾流驰振为研究对象,在风攻角为0°~20°的条件下,主要通过风洞试验研究了下游圆柱发生尾流激振的起振条件、振动幅度和运动轨迹,研究了提高结构阻尼比的减振效果,讨论了尾流驰振的雷诺数效应,结合静止双圆柱绕流场的大涡模拟结果对尾流干扰机理进行了探讨。研究表明：在某些风攻角下,下游圆柱的尾流致涡激共振振幅远大于单圆柱涡激共振振幅;在0°以外的其他风攻角下,下游圆柱均发生大幅尾流驰振,但小攻角（5°和10°）与大攻角（20°）下的尾流驰振现象有明显差别,很可能存在不同的流场激励机理;风攻角为15°时,下游圆柱的尾流驰振有明显的雷诺数效应,其动力响应特性与经典驰振不同,下游圆柱起振后的振幅和运动轨迹随雷诺数（风速）的增大呈现复杂的变化形态;提高结构阻尼比可有效抑制下游圆柱的尾流致涡激共振,但对尾流驰振的减振效果不佳。Parallel cables, which are used extensively in long span cable-supported bridges, usually suffer wake-induced vibra- tions. Wake-induced vortex excitation and wake galloping of two tandem and staggered circular cylinders have been studied by wind tunnel tests. Flow around two stationary circular cylinders is obtained by Large Eddy Simulation to analyze the mecha- nism behind the wake galloping. The center-to-center distance of the two cylinders is 4 diameters and the attack angles are 0°, 5°, 10°, 15° and 20°. It is found that except the case with the attack angle of 0~, large-amplitude wind-induced galloping occurs in other four attack angles. However, the trajectories of vibration in small attack angles （5° and 10°） are very different from those of large attack angle （20°）. For the cases with small attack angles, the downstream cylinder moves almost in across wind directions, while trajectories for the vibration of large attack angles move both in along-wind and across-wind directions. This phenomenon indicates that different excitation mechanisms may exist according to attack angles. For the case of attack angle 150, the motion characteristics show significant Reynolds number effects, with trajectories of vibration changing from one pat- tern to another at difference Reynolds numbers. Increasing the structural damping ratio can mitigate the wake-induced vortex excitation effectively, but has complicated effects on the wake-induced galloping.

关 键 词：并列索 尾流激振 风洞试验 雷诺数效应 振动控制 

分 类 号：U448.25[建筑科学—桥梁与隧道工程] U448.27[交通运输工程—道路与铁道工程]