覆冰导线动态气动力特性模拟与分析

为研究覆冰导线舞动时气动力的特性，从弱耦合角度出发，基于流体动力学仿真软件Fluent二次开发，利用用户自定义函数对导线的舞动轨迹进行编程并结合动网格技术实现流固耦合。计算了新月形覆冰导线在横向振动下的气动力系数，并与静态模拟结果和试验结果进行比较；分析了舞动幅值、频率和扭转振动对动态气动力的影响。结果表明：相同风速下，动态气动力系数大于静态值，二者具有相同的变化规律；阻力、升力系数随舞动幅值增大显著增加，特别是升力系数成倍增加；振动频率增加，也使动态气动力系数增大，但频率对动态气动力的影响小于幅值的影响；扭转振动对动态气动力有一定的影响。工程中采用静态气动力系数预测大档距舞动引起的断线的临界风速和塔承受的荷载，其结果不安全，应考虑动态气动力系数对舞动的影响。

Numerical simulation and analysis of dynamic aerodynamic characteristics of iced conductor

In order to study the aerodynamic characteristics of galloping of iced conductor, based on software Fluent redevelopment, the user-defined function described the track of conductor galloping and dynamic mesh technology were used to realize the fluid and solid coupling from the weak coupled model. The aerodynamic coefficients of crescent iced conductor in the lateral vibration were calculated, and compared with the results from simulation that conductor in static and experiment；the effects of galloping amplitude, frequency and torsion vibration on the dynamic aerodynamic forces were analyzed. The results show that the dynamic aerodynamic coefficients are larger than that of static, and they have the same variation laws under the same wind speed. Drag and lift coefficients increase significantly with the galloping amplitude increasing, especially the lift coefficient multiplied. The frequency increase also makes the dynamic aerodynamic coefficients increasing, but the effect of frequency on the dynamic aerodynamic force is less than that of amplitude. Torsion vibration has a certain influence on the dynamic aerodynamic force. When the static aerodynamic coefficients are used to forecast of the critical wind speed of conductor break and tower loads caused by large span galloping in engineering, the results tend to unsafe. The effects of dynamic aerodynamic coefficients on galloping should not be ignored.