输电塔气动力系数和气动导纳风洞试验研究  

Wind tunnel test for aerodynamic coefficient and aerodynamic admittance of a transmission tower

作　　者：邓洪洲[1] 司瑞娟[1] 段成荫[1] 胡晓依[1] 

机构地区：[1]同济大学建筑工程系,上海200092

出　　处：《振动与冲击》2015年第3期188-195,共8页Journal of Vibration and Shock

摘　　要：输电塔结构的非定常抖振力与来流风速之间存在复杂的非线性关系,基于风洞试验得到的某1 000 k V格构式直线输电塔弹性模型的基底力以及参考高度处同步采集的风速时程,采用线性和高斯两种近似假定计算了非定常气动力系数并与试验值进行了比较;提出了包含结构气动阻尼效应在内的总气动导纳的概念,通过基底脉动力谱和来流脉动风速谱的比值对总气动导纳函数进行识别,并用基于频域相干函数对导纳函数的线性部分进行了估计。结果发现,风偏角线性近似所计算静气动力系数的偏差较高斯近似小;由于气动抖振力非定常性质明显,不考虑总气动导纳函数将高估输电塔模型的抖振响应;脉动风力与脉动风速间有较强的非线性关系,用线性导纳函数计算的抖振力谱将低估脉动风分量的影响。Buffeting forces of structures,such as,transmission tower usually have a complex nonlinear relation to incoming wind fluctuations.Based on wind forces and simultaneous fluctuating wind speed time history measured from a wind tunnel test on a model of 1000 kV suspension transmission tower,the aerodynamic coefficients and aerodynamic admittance functions of the tower were studied.Unsteady aerodynamic coefficients obtained in the test were compared with those estimated starting from linear and Gaussian assumptions.The concept of total aerodynamic admittance including structural aerodynamic damping effect was proposed.It was identified with ratio of power spectral density of wind force to that of fluctuating wind speed.The linear admittances representing correlated parts of the wind speeds and wind forces were estimated by employing frequency-domain coherence functions. Results showed that the linear assumption of relationship between time-dependent wind angle of attack and associated aerodynamic coefficient has a higher accuracy than that of Gaussian assumption;because of the unsteady nature of wind-speed-to-wind-force relation,neglecting aerodynamic admittances leads to higher estimation of the buffeting responses of the tower;moreover,the effects of wind fluctuations are underestimated with linear admittances in spite of the stronger nonlinearity between wind speed and wind force.

关 键 词：输电塔 风洞试验 气动系数 气动导纳 抖振响应 

分 类 号：TM753[电气工程—电力系统及自动化] TU317.1[建筑科学—结构工程]