三维覆冰斜拉索风致振动驰振分析

斜拉索偏心覆冰后，气动外形不再稳定，在风的作用下，可能诱发驰振。大幅的驰振将威胁到拉索结构的安全，因此，有必要对覆冰拉索的驰振稳定性进行深入的研究。应用FLUENT中的SST k-ω模型对三维覆冰斜拉索的绕流场进行数值模拟，得到全攻角下的阻力系数、升力系数及驰振力系数，依此判定覆冰斜拉索是否发生驰振，并得到某大跨斜拉桥部分斜拉索的驰振临界风速。结果表明：经过三维模拟计算的覆冰拉索的部分驰振力系数小于零，并且驰振临界风速较小，斜拉索易发生覆冰驰振；与风洞试验和二维模拟数据比较，三维覆冰斜拉索模拟获得的气动力系数比二维更接近试验值。

Galloping Analysis of Wind-induced Vibration for 3D Stay Cables with Iced Accretion

The stay cables with iced accretion have the off-centered section, and the aerodynamic shape is no longer stable. It maybe lead to galloping vibration by the effect of wind. A giant galloping vibration will threaten the security of stay cables, so it is necessary to analyze in depth galloping stability of stay cables with iced accretion. The flow field of 3D iced cables was simulated with applying SST k-ω model of FLUENT. The drag, lift and galloping coefficients of whole angle were computed to estimate the possibility of gallop. And critical galloping wind speeds of stay cables of cable-stayed bridge were obtained. The results show that part of galloping coefficients of iced cables are less than zero which were computed by 3D simulation, and the critical galloping wind speeds are small. The stay cables are prone to galloping vibration; compared with the wind tunnel test and 2D simulation data, the aerodynamic parameters were computed by 3D simulation of iced cables is more close to the test value than 2D simulation.