风速和风偏角对斜拉索风雨激振的影响

Effects of Wind Speed and Wind Deflection Angle on Rain-wind Induced Vibration of Stay Cable

基于滑移理论建立了斜拉索风雨激振双向耦合理论模型,应用COMSOL与MATLAB相结合的自编译程序计算不同风速以及风偏角条件下随时间变化的气动力系数、斜拉索振动响应以及表面水膜形态变化,并分析了三者之间的关系,得到了不同风速以及风偏角条件下的斜拉索风雨激振现象的变化规律。结果表明风偏角的改变对斜拉索风雨激振起振区间范围影响不大;在起振区间内,斜拉索振幅随风偏角的增大,先增加后减小,风雨激振发生时,风偏角为22.5°的斜拉索振幅最大;一定风速范围内,风偏角大小不变时,斜拉索振幅随风速增加都是先增大后减小的规律;当上水线厚度较大且其振动频率与斜拉索自振频率相接近时,斜拉索与水线之间发生同频谐振,斜拉索会发生大幅振动。

Based on the lubrication theory,a two-way coupled theoretical model of rain-wind-induced vibration(RWIV)of stay cable was established.The transient aerodynamic coefficients,stay cable vibration response,the evolution of water film,and the relationship between them are analyzed by using a self-compiled program combining COMSOL and MATLAB.The variation disciplines of the RWIV at different wind speeds and wind angles are obtained.The results show that the change of wind deflection angle has little effect on the range of wind speed which induces RWIV.Within the right interval,the vibration amplitude of stay cable increases first and then decreases with the increase of the wind deflection angle.When RWIV occurs,the cable vibration amplitude with the wind declination angle of 22.5°is the largest.Within a certain wind speed range,when the wind declination angle is constant,the amplitude of the stay cable amplitude increases first and then decreases with the wind speed increasing.When the thickness of the water film is large and its evolution dominant frequency is close to the natural frequency of the cable,the co-frequency resonance may occur between the cable and the waterline,which may induce RWIV.