以Tacoma大桥风振致毁事故为例，研究H型桥面的风振机理．分析了绕流场对称性的破缺及其诱发桥面振动的情况；并根据大桥实际尺寸，采用Fluent软件进行了二维仿真计算．结果表明：桥面低压区从中部逐步形成并顺风向移动，在上下桥面依次交替进行；其二，风速越大，桥面所受的阻力和升力变化周期越小，周期变化速率也越小；其三，升力系数的变化周期约为阻力系数变化周期的两倍，在当时19m／s的风速条件下，升力系数变化的周期约为31．5s．%This paper took Tacoma Narrow Bridge accident caused by wind vibration for an example, researched mechanism of the bridge vibration on the H-type bridge deck and analyzed flow symmetry breaking and conditions of the bridge vibration induced by the flow around. Based on the actual size of bridge deck, two-dimensional numerical calculation was set up by Fluent software. The results showed that the low pressure area was gradually formed from the middle region, moved down wind and changed alternately and periodically on the upper and lower bridge deck; Secondly, the bigger the wind speed, the smaller the variance period of bridge resistance force and lift force and the rate of period variance; Thirdly, the variance period of lift coeffi- cient was two times of resistance coefficient, and the variance period of lift coefficient was around 31.5 s, with the wind velocity is 19 m/s.
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