Detouring flow symmetry breaking has important effect on slenderness structure.It can induce structural vibration and seriously affect the reliability and safety of the structure.Based on circular cylinder flow models

vertical and horizontal symmetry breaking of circular cylinder flow for viscous fluid is analyzed systematically.In order to get deep understanding of theoretical results

computer simulation for circular cylinder flow is carried out with Fluent software and circular cylinder flow conditions are analyzed in detail at Reynolds numbers of 10

20

40

100

200

2000 and 20000.Results show that the horizontal symmetry breaking of circular cylinder flow start to appear at Re=200.On the basis

an accident of Tacoma Narrow Bridge damage caused by wind vibration is taken as an example.The undulated vibration of the bridge deck due to alternate vortex synchronous shedding and the twist vibration due to alternate vortex asynchronous shedding are discussed respectively.According to the results

the symmetry breaking of circular cylinder flow is the direct cause of the bridge vibration damage.