波浪形斜拉索的气动力及风致振动特性

Aerodynamic Forces and Wind Induced Vibrations Characteristics of Wavy Stay Cables

斜拉索的风荷载和风致振动问题在工程设计和抗风研究领域备受关注,探索具有较小气动力和良好抑振性能的新型斜拉索十分必要.针对某一特定几何尺寸的波浪形斜拉索,通过风洞试验方法,研究了该波浪形斜拉索的整体气动力、风压分布、局部气动力、涡激振动和干索驰振特性.结果表明:在1.00×10^(5)~3.86×10^(5)的雷诺数范围内,波浪形斜拉索的平均阻力系数总体而言小于标准斜拉索,在低雷诺数范围可减阻18%,最大平均升力系数相比标准斜拉索可降低80%;波浪形斜拉索的风压分布、气动力随雷诺数的整体变化规律与标准斜拉索相似,但展向相关性较弱;波浪形斜拉索的涡激振动性能显著优于标准斜拉索,最大振幅降低34%,最大振幅对应的风速提高了16%;干索驰振性能与标准斜拉索的结果相当,最大振幅可减小5%,但发生振动的风速范围更宽.

Wind load and wind-induced vibrations of stay cables are of great concern in engineering design and wind resistance research fields.Therefore,it is necessary to explore a new type of stay cable with less aerodynamic force and excellent wind-resistant performance.To this end,a wavy stay cable was employed to study the overall aerodynamic forces,wind pressure distribution,local forces,vortex-induced vibration and dry galloping characteristics,based on a wind tunnel test.The test results indicate that,during the Reynolds number range of 1.00×10^(5)~3.86×10^(5),mean drag coefficients of the wavy stay cable are generally less than those of regular stay cables,with a maximum reduction of 18%in low Reynolds numbers.The maximum mean lift coefficients are decreased by around 80%.Variation in wind pressure distribution and aerodynamic forces with the Reynolds number is almost identical to those of regular stay cables,except for weaker spanwise correlation.The vortex-induced vibration is significantly suppressed by the wavy stay cable,whose maximum amplitude is decreased by 34%and the corresponding velocity is increased by 16%.However,dry galloping is nearly the same as regular stay cables,whose maximum amplitude is decreased by 5%and sustained wind velocity range is wider.