悬浮隧道锚索流固耦合振动试验研究

摘要

Submerged floating tunnel(SFT)is a new traffic structure across long and deep waterway.The vortex-induced vibration (VIV)of cables may occur under the action of water current.Even through numerous previous studies have been done by using numerical methods,however,experiment is an indispensable mean to explore the VIV mechanism of cables in water.Taking the cables of Qiandao Lake SFT as the prototype,the experiments of VIV on cables were carried out under the action of current by using segment models in a stormy stream integrated sink.The results show that the inertial force coefficient Cm of circular cable is 0.94,the linear fluid damping ratio ξ'is 1 .26%;when the reduced velocity is between 5.8 and 1 0.1 ,the vortex-induced resonance will occur,the maximum lateral amplitude Ay /D is 1 .1 0,the in-line amplitude is still low,and the lift coefficient CL and drag coefficient CD obviously increase.By the parametric analysis it is concluded that the diagonal arrangement of circular cables is helpful to reduce the VIV effects and the changing of flow direction will adversely affect the vibration of inclined cables.%悬浮隧道跨越长深水域的新型交通结构物。在水流的作用下，锚索将会发生涡激振动，以往的研究主要采用数值方法，而进行模型试验研究是探索悬浮隧道锚索涡激振动机理不可或缺的研究手段之一。利用风浪流多功能水槽，以千岛湖悬浮隧道锚索为原型，采用节段模型试验的方法，进行了均匀流作用下锚索涡激振动试验研究。通过试验发现，圆形锚索的 Cm值约为0．94，线性流体阻尼比ξ′约为1．26％；锚索在约化速度 U／fn D ＝5．8～10．1发生涡激锁定现象，产生涡激共振，此时横向振幅约化值（Ay ／D）最大达到1．10，顺流向振动依旧较小，而升力系数 CL和拖曳力系数 CD均会显著的增大；参数分析发现，圆形锚索倾斜布置有利于降低涡激共振的不利影响，但当来流角度的变化后会对倾斜布置的锚索产生不利影响。