桥梁断面两个涡振锁定区间的数值模拟研究  

Numerical simulation for two separate vortex-induced vibration HUANG Lilock-in intervals of bridge sections

作　　者：黄俐[1] 周帅[2] 梁鹏 

机构地区：[1]华南农业大学水利与土木工程学院,广州510642 [2]湖南大学风工程试验研究中心,长沙410082 [3]中交四航局第一工程有限公司,广州510310

出　　处：《振动与冲击》2016年第11期47-53,73,共8页Journal of Vibration and Shock

基　　金：国家自然科学基金(91215302;51278189);广东省自然科学基金(2015A030310164)

摘　　要：对于某类大宽高比桥梁断面或者钝体形式断面,在基于同一组试验参数的节段模型风洞试验中,能够实测到相同振型两个分离的涡振锁定区间现象,并且两个区间内振动频率一致,这与一个断面对应一个Strouhal数的理论不相符合。为了进一步研究这类非常规振动形式的气动机理,以一组宽高比为6的矩形断面为研究对象,基于风洞试验中实测的两个独立的涡振锁定区间响应数据,采用流体动力学软件Fluent开展了相应的数值模拟研究。数值计算获取了与风洞试验一致的两个独立分离的涡振锁定区间风振曲线,并且在区间跨度以及幅值关系上均吻合良好,然后通过Fluent提取了前后两个涡振锁定区间内的气动力和尾流漩涡进行了对比研究。研究结果表明,第一个锁定区间内的尾流漩涡呈现出经典的卡门涡街形态,第二个区间内的尾流涡模态则主要表现为非典型的"鱼尾摆动"形态,两个涡振区间的尾流形态完全不同;在两个独立的锁定区间内,气动升力与位移响应之间始终存在着相位差,并且均随着锁定区间的发展而持续增大,第一个锁定区间相位差的跳跃程度明显大于第二个锁定区间。For some bridge sections or similar bluff bodies with a large aspect ratio,two separate vortexinduced vibration(VIV)lock-in intervals of the same model shape can be observed in the same section model wind tunnel tests,and the dominant oscillation frequencies of the two lock-in intervals are the same,these do not agree with the traditional Strouhal law.In order to get a further understanding aerodynamic mechanism of these oscillations,a rectangular section with an aspect ratio of 6 was taken as a study object,and based on its 2D section model wind tunnel tests parameters and results,Fluent-based numerical simulations were performed.The simulation results agree well with test ones in both lock-in ranges and amplitude responses.Then,more details about aerodynamic forces and wake vortices were obtained using the post processing of Fluent.The study showed that the wake vortices of the first VIV lock-in interval is the typical Karmen vortex mode,while the second one is full different from the first one,its wake vortices are observed to be'fish tail waving'mode;in the two separate lock-in intervals,there is always a phase difference between aerodynamic lift and vertical displacement response,and the phase difference continuously increases with developing of the lock-in interval;moreover,the jump of the phase difference of the first lock-in interval is bigger than that of the second one.

关 键 词：桥梁 涡振 锁定区间 数值模拟 尾流漩涡 

分 类 号：U446.1[建筑科学—桥梁与隧道工程]