临界雷诺数区准椭圆形覆冰导线风压特性研究

采用刚性模型进行测压试验,得到了不同雷诺数下准椭圆形覆冰导线的风压分布规律,通过对比平均风荷载、脉动风荷载及风荷载谱等参数,分析了雷诺数对风荷载以及横风向驰振稳定性的影响。当雷诺数达到临界区,与亚临界区的对应值相比,平均阻力系数下降、平均升力系数随风向角变化幅度大且在某些对称工况产生横风向平均升力系数;平均风压系数分布对风向角等参数更为敏感。旋涡脱落由亚临界区的规则脱落变为不规则脱落,周向风压相关性减弱,特征频率消失。临界区内平均升力系数急剧的下降段使得结构更易发生横风向驰振。

Study on wind pressure characteristics on quasi-oval shaped iced conductor at critical Reynolds numbers regime

By employing the rigid model wind pressure test,the wind loads distribution on quasi-oval shape iced conductor is obtained at different Reynolds numbers,and the effects of Reynolds number on wind loads as well as galloping stability in the direction transverse to the mean wind direction are analyzed by comparing the mean wind loads,fluctuating wind loads and wind force spectra.When the Reynolds number reaches the critical range,compared to the situation at sub-critical range,the mean drag coefficients decrease,and mean lift coefficients occur at the symmetric case and severely vary with the wind direction;wind pressure coefficients are sensitive to the wind directions.Vortices shedding,which is supposed to be regular at subcritical range,is irregular at critical range;the correlation of wind pressure around the cross section is weakened,and predominate frequency disappears.The steep slope of the lift coefficient versus angle of attack corresponding to Reynolds number at critical range makes the galloping in the direction transverse to the mean wind direction easy to happen.