直径30cm圆柱的气动力参数和绕流特性研究  

Aerodynamic coefficient and flow characteristics of a 30 cm-diameter circular cylinder

作　　者：沈国辉[1] 姚剑锋[1] 郭勇[2] 邢月龙[2] 楼文娟[1] SHEN Guohui;YAO Jianfeng;GUO Yong;XING Yuelong;LOU Wenjuan(College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China;Electric Power Design Institute of Zhejiang Province,Hangzhou 310007,China)

机构地区：[1]浙江大学建筑工程学院,杭州310058 [2]浙江省电力设计院,杭州310007

出　　处：《振动与冲击》2020年第6期22-28,共7页Journal of Vibration and Shock

基　　金：国家自然科学基金(51178425,51838012)。

摘　　要：为研究光滑圆柱的气动力系数和绕流特性,在均匀流中进行不同风速下的测压风洞试验,试验获得了阻力系数、升力系数、表面风压分布、风压相关性系数、斯托罗哈数等随雷诺数的变化特征,并将试验结果与以往结果进行比较。研究表明:升力系数的脉动值大于阻力系数的脉动值,说明涡脱造成的横风向激励比顺风向紊流激励剧烈;雷诺数位于临界区域时,圆柱表面风压分布呈现出对称-不对称-对称的变化过程,反映了由层流分离转化为湍流分离的全过程;在雷诺数为352000时呈现一侧为层流分离、另一侧为湍流分离的临界流态,风压呈现出左右不对称的单边泡形式;获得层流分离和湍流分离时的表面风压相关性分布特征,层流分离时圆柱同一侧的风压测点均呈较强的正相关,而湍流分离时在分离点前的区域相关性较强,分离点之后的区域相关性较弱;层流分离的升力系数谱有显著的峰值,表明尾流是规则的漩涡脱落,而湍流分离的升力系数谱没有明显峰值,表明尾流是随机的漩涡脱落。In order to study the aerodynamic coefficients and flow characteristics of a smooth circular cylinder,wind pressures on the cylinder were measured at different wind speeds in a uniform flow simulated in a wind tunnel.The variation of the drag coefficient,lift coefficient,surface wind pressure distribution,wind pressure correlation coefficient and Strouhal number of the cylinder with respect to the Reynolds number were obtained.And the above results were compared with those of the previous researches.The results show that the fluctuation of the lift coefficients is larger than that of the drag coefficients,indicating that the vortex shedding induced by cross-wind excitation is more significant than that induced by along-wind turbulence.When the Reynolds number is in the critical flow region,the wind distribution around the cylinder experiences a symmetry-asymmetry-symmetry transition,revealing a whole changing process from laminar flow separation to turbulent flow separation.When the Reynolds number equals 352000,a critical flow with laminar flow separation on one side and turbulent flow separation on the other side occurs and the wind pressures around the cylinder present a unilaterally asymmetrical bubble form.The characteristics of wind pressure correlation during laminar flow separation and turbulent flow separation were obtained.The wind pressures on the same side of the cylinder are highly correlated in the laminar flow separation case.Whereas,the wind pressures in the flow region before the separation point are highly correlated and those in the flow region after the separation point are weakly correlated in the turbulent flow separation case.The spectrum of lift coefficient has an obvious peak in the turbulent flow separation case,indicating that the fluctuation of the wind pressures is induced by the periodical vortex.The spectrum of lift coefficient has no obvious peak in the turbulent flow separation case,indicating that the fluctuation of the wind pressures is induced by the random vortex.

关 键 词：圆柱 风洞试验 气动力气数 风压分布 斯托罗哈数 

分 类 号：TU312[建筑科学—结构工程]