风雨激振时水膜形态与拉索振动间的双向耦合

TWO-WAY COUPLING BETWEEN WATER FILM MORPHOLOGY AND RAIN-WIND INDUCED VINRATION OF CABLE

风雨激振是指斜拉索在特定风雨条件下的一种低频大幅度振动。该文应用滑移理论并结合单自由度振动理论建立耦合的水膜运动方程和拉索运动方程,应用计算流体力学软件Fluent求解水膜运动方程中的风压力系数和摩擦系数,通过数值求解方程组来研究水膜形态变化、拉索升力及其振动响应之间的联系,以揭示风雨激振的产生机理。结果表明:拉索表面水膜形态的周期性变化导致拉索升力的周期性变化,从而引起拉索的大幅度振动;水线与拉索间的共振是产生风雨激振现象的主要原因。

Rain-wind induced vibration(RWIV) is the phenomenon that a stay cable may vibrate with a large amplitude and a low frequency under the special conditions of wind and rain. According to lubrication theory and vibration theory of a single-mode system, the coupled equations of water film evolution and cable vibration are presented. The wind pressure and friction coefficients in water film evolution equations are obtained by computational fluid dynamics(CFD) software-Fluent. To reveal the mechanism of RWIV, the relationships between the water film morphology, the lift and vibration of a cable are discussed by numerical solving the coupled equations. The results show that cable lift oscillates periodically due to the periodical variation of water film morphology, which causes the large amplitude vibration of a cable. This confirms the conclusion that the main reason for RWIV is the resonance between rivulets and a cable.