正弦风场覆冰导线静态气动力系数

Analysis of aerodynamic coefficients of iced conductor under sine wind

为研究脉动风场对覆冰导线气动力特性的影响,基于流体动力学软件Fluent,计算了新月形覆冰导线在正弦变化风场下的气动力系数,并与定常风场下的模拟结果进行比较;分析了脉动风的频率和幅值对气动力的影响.结果发现:气动力系数也呈正弦规律变化,其平均值(或绝对值)大于定常风场下的数值,二者随攻角的变化规律相同;脉动风频率大于1 Hz(短周期脉动)时,随频率的增加,气动力系数出现峰值的时间前移,阻力系数和扭转系数的平均值明显减小,幅值变化增大,升力系数的平均值则明显增加,幅值变化减小;脉动风幅值增加时,气动力系数明显增大,且其前半周期随幅值的变化比后半周期的变化要大,具有不对称性.因此工程中预测由导线舞动导致的塔承受载荷以及输电线路防舞设计时,应考虑脉动风场气动力系数对舞动的影响.

In order to study the effect of unsteady wind on aerodynamic characteristics of iced conductor, the aerodynamic coefficients of crescent iced conductor in sinusoidal variation wind were calculated based on software Fluent, and compared with the results from simulation in steady wind;the effects of frequency and amplitude in unsteady wind on the aerodynamic forces were discussed. The results show that the aerodynamic coefficients have sine tend of change, their average values （or absolute values） are larger than that in steady wind, and they have the same variation tends with attack angles. When frequency of unsteady wind is bigger than 1 Hz （short period of oscillating）, with the increase of frequency, the peak time of aerodynamic coefficients move forward, the average values of both drag and torsion coefficients decrease greatly and their amplitude change ranges increase; the average value of lift coefficient increase significantly and its amplitude change range decreases. When amplitude of unsteady wind increases, aerodynamic coefficients increase obviously, they have asymmetry and their varieties are larger in first half period than that in second half period. So the effects of aerodynamic coefficients under unsteady wind on galloping should take into account for forecast tower loads caused by galloping and anti-galloping design of transmission lines in engineering.