不同厚宽比矩形截面柱体涡激振动的数值研究  

Numerical study on the vortex-induced vibration of a rectangular cross section cylinder with different side ratios

作　　者：祝瑜哲 陈伏彬[1] ZHU Yuzhe;CHEN Fubin(School of Civil Engineering and Architecture,Changsha University of Science&Technology,Changsha 410114,China)

机构地区：[1]长沙理工大学土木工程学院,长沙410114

出　　处：《振动与冲击》2024年第10期73-81,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金项目(52278479);湖南省自然科学基金项目(2023JJ30016);长沙理工大学研究生科研创新项目(CSLGCX23144)。

摘　　要：厚宽比的变化将导致矩形截面柱体周边流场的变化,进而影响结构气动性能及其涡激振动响应。基于Fluent软件平台,以雷诺数22 000的二维矩形截面柱体为对象,结合重叠网格技术与四阶龙格-库塔法,研究了厚宽比对其涡激振动的影响,从流场角度进行了影响机理分析。首先,选择厚宽比D/B=0.25的矩形截面,将计算结果与相关文献试验与模拟对比,验证了模拟方法及参数设置的有效性;然后,从气动力系数统计值及自谱、流向与横风向振幅变化以及相位转变等角度,对比分析了厚宽比对结构涡激振动响应的影响;最后,从瞬态流场的角度,分析了不同折减风速对柱体尾涡脱落的影响。结果表明,在柱体截面面积不变时,较小厚宽比柱体的涡振响应极为微弱,气动性能也明显低于大厚宽比柱体,大厚宽比柱体的气动性能及涡振响应高于标准方柱,振幅也会在较低折减风速下发生突变,但会在较高折减风速下达到振幅峰值。比起圆柱等结构,分离角固定的矩形柱体的尾涡脱落模式对折减风速的变化并不敏感,这一特征在大厚宽比方柱上表现更为明显。The change of the side ratio(D/B)for a rectangular cross section cylinder will lead to the variation of the surrounding flow field,affecting the aerodynamic performance and vortex-induced vibration(VIV)response of the cylinder.Based on the Fluent platform,the effects of side ratio on the vortex-induced vibration of a two-dimensional rectangular cross section cylinder with Reynolds number 22000 were studied by combinedly using the overset grid technology and the fourth-order Runge-Kutta method.Firstly,a rectangular section with the side ratio of D/B=0.25 was selected,and the effectiveness of the simulation method and parameter setting was verified by comparing the calculated results with the results in relevant literature tests and simulations.Then,the effects of the side ratio on the VIV response of the rectangular cross section cylinder were compared and analyzed in of terms the statistical values of aerodynamic force coefficients,the self-spectrum,the amplitude changes in the flow and transverse direction,and the phase transition.Finally,the influence of different reduced velocity on the wake vortex shedding was analyzed from the respect of transient flow field.The results show that,when the section area of the cylinder is fixed,the VIV response of the cylinder with a small side ratio is very weak,and the aerodynamic performance is significantly lower than that of the cylinder with a large side ratio.The aerodynamic performance and VIV response of the cylinder with a large side ratio are higher than those of the standard square cylinder.The amplitude ratio of the cylinder may also change abruptly at a lower reduced velocity,but will reach the peak amplitude at a higher reduced velocity.Compared with the cylindrical structure,the vortex shedding mode of the rectangular cylinder with fixed separation angle is less sensitive to the change of the reduced velocity,which is more obvious on the large side ratiorectangular cylinder than the square cylinder.

关 键 词：数值模拟 厚宽比 涡激振动 折减风速 振幅比 瞬态流场 

分 类 号：O353.1[理学—流体力学]