The dry galloping mechanism of stay cables was studied by means of CFD simulations and wind tunnel tests.Firstly,CFD simulations with 2-D and 3-D cable models were conducted by utilizing the LES method based on FLUENT software to obtain wind pressure coefficients,mean drag and lift coefficients,correlation coefficients of fluctuating aerodynamic forces along the cable axis.Secondly,wind tunnel tests using the particle image velocimetry (PIV) technique were performed to specially investigate characteristics of stay cable wake flow.The results showed that a sudden decrease in mean lift coefficient of a 3-D stay cable is observed,and a maximum minus galloping force coefficient -4.74 is found,so large amplitude galloping vibration of the stay cable is possible to take place;correlation coefficients between aerodynamic forces of a 3-D cable's cross sections are smaller than those of a 2-D cable,and correlations of drag coefficients are smaller than those of lift coefficients;the axial flow in a 3-D cable's wake flow is not very obvious;the effects of axial flow on cable galloping vibration need further quantitatively studying.%采用数值模拟和风洞试验方法,对斜拉索干索驰振机理进行研究.基于FLUENT商业软件平台,研究斜索和直索的风压系数、平均气动力系数、脉动气动力系数的轴向相关性等;进行粒子图像测速(PIV)风洞试验,对斜索尾流进行可视化显示,研究斜拉索背后的轴向流特性.研究结果表明:斜索的平均升力系数在特定的倾角和风攻角下会发生突降,其驰振力系数为较大的负值(-4.74),可能会发生驰振;斜索各截面气动力的轴向相关系数比直索要小,甚至会出现负的相关系数;在平均气动力系数突降的风攻角下,尾流中的轴向流不是非常明显,轴向流对于干索驰振的影响值得进一步定量研究.
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