斜拉索表面水膜形态及斜拉索气动力变化规律

斜拉索表面水线的形成与振荡是斜拉索发生风雨激振的重要原因之一.为研究水线运动与风雨激振现象间的内在联系,本文将滑移理论与计算流体力学相结合,考虑斜拉索表面水膜形态对风压力系数和风摩擦力系数的影响,建立了一个模拟风雨条件下斜拉索表面水膜形态变化的理论模型;在此模型基础上推导出风雨作用下斜拉索气动力计算公式,通过数值模拟得到不同风速下的斜拉索表面水膜形态及气动力变化规律,分析二者间的内在联系.与已有的试验结果对比发现:当斜拉索发生风雨激振现象时,水线形态变化与气动力变化频率相同,且接近拉索的自振频率,说明风雨激振现象的产生原因是水线形态的周期性变化引起拉索的共振.

Variation of Water Film Morphology and Aerodynamic Force of Stay Cable

The formation and oscillation of rivulets around stay cable play an important role in rain-wind induced vi-bration （RWIV）. To study the influence of rivulet motion on the RWIV of stay cable, with lubrication theory andcomputational fluid dynamics method combined, a theoretical model for simulating the morphological change ofwater film around stay cable under wind and rain is presented, and a formula for the aerodynamic force of stay cableis derived from water-film motion equation. The variations of water film morphology and aerodynamic force of staycable are obtained by numerical simulation, and the internal relationships between them are analysed. Compared withthe existing experimental results, it can be found that when RWIV of stay cable occurs, the change frequencies ofrivulet morphology and aerodynamic force are close to the natural frequency of stay cable, which indicates that thecause of RWIV is the resonance of cable induced by the periodic change of rivulet morphology.