桥梁吊杆索尾流驰振问题的数值研究

Numerical investigation of wake galloping of suspension bridge cables

对一座大桥长吊杆索的尾流驰振问题进行了数值研究。基于Reynolds平均的非定常N-S方程和SST k-ω湍流模型,采用商业CFD软件FLUENT对串列双吊杆索的绕流流场进行了数值模拟,得到了不同工况下下游吊杆索气动力的瞬时值、时间平均值及其气动导数。在此基础上进行的上游吊杆索尾流中的下游吊杆索的稳定性分析发现,在设计参数下,当攻角较大或较小时是稳定的,但在攻角的中间范围是不稳定的,会发生尾流驰振现象。该结果与传统理论一致,为该桥的增设阻尼器的必要性提供了依据。

Wake galloping of the longest suspension cable on a bridge was numerically investigated using the commercial software FLUENT to simulate the plane flows around sections of the cables using the SST k-w turbulence model to obtain the instantaneous and time-averaged aerodynamic forces and their derivatives. Stability analysis of the downstream cable in the wake flow of the upstream cable shows that the downstream cable is stable when the attack angle is very small or very large, but is unstable at moderate attack angles, which agrees with traditional theories. The results also indicate that dampers are necessary to prevent wake galloping of the bridge cables.