VOF法在斜拉索风雨激振数值模拟中的应用

Application of VOF method to numerical simulation of rain-wind induced vibration of stay cable

将气液两相流理论与体积分数法(VOF法)相结合,提出一种模拟发生风雨激振现象时斜拉索表面水线形成和运动的新方法;应用这一方法采用计算流体软件CFX进行数值模拟得到拉索表面水线运动规律和拉索气动力;将气动升力施加到拉索上得到拉索的振动响应;通过与风洞试验结果及混合子结构方法的计算结果进行比对,验证了这一方法的准确性与合理性;通过分析水线运动、拉索气动力变化与拉索振动间的内在联系,揭示风雨激振现象的产生机理:上水线的环向周期性振荡导致拉索升力的周期性变化,引起拉索发生大幅度振动,上水线与拉索间的共振是产生风雨激振现象的主要原因。

A new method of simulating the evolution of rivulets on the stay cable surface is presented combining gas-liquid twophase theory and the volume of fluid method（VOF method）.Using this method,the evolutions of rivulets,the aerodynamic forces of cable were obtained by computational fluid dynamics（CFD）software CFX.The vibration response of the cable can be obtained by applying the aerodynamic lift to a single-degree-of-freedom model.The veracity and rationality of this method are verified through the comparison with the experimental results and computational results obtained using hybrid approach.Through discussing the relationships between rivulets motion,viration of aerodynamic forces and vibration of cable,the mechanism of rain-wind induced vibration（RWIV）is revealed,that is,cable lift oscillates periodically due to the periodical oscilation of the upper rivulet in circumferential direction,which causes the large amplitude vibration of the cable.Thus the resonance between upper rivulet and cable causes RWIV.