刚性耦合三圆柱流致振动特性和机制  

Oscillation responses and mechanisms of three rigidly coupled circular cylinders

作　　者：刘旭菲 陈威霖[2] 及春宁[2] LIU Xufei;CHEN Weilin;JI Chunning(School of Water Conservancy and Environmental Engineering,Zhejiang University of Water Resources and Electric Power,Hangzhou 310018,China;State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300072,China)

机构地区：[1]浙江水利水电学院水利与环境工程学院,杭州310018 [2]天津大学水利工程仿真与安全国家重点实验室,天津300072

出　　处：《振动与冲击》2022年第12期1-7,共7页Journal of Vibration and Shock

基　　金：国家自然科学基金(51709138,51779172);天津市自然科学基金(16JCQNJC07300)。

摘　　要：采用迭代式浸入边界法对刚性耦合三圆柱的流致振动进行了数值模拟研究。三圆柱按照等边三角形排列,上游两个并排圆柱,下游一个圆柱。圆柱间距比为P/D=1.0~4.0,雷诺数为Re=100,质量比为m=2,折合流速为U_(r)=3~30。通过研究圆柱的振幅、频率和流体力随折合流速的变化规律,发现了两种不同的振动模式,即小间距比条件(P/D=1.0)下的驰振模式和中、大间距比条件(P/D=1.6~4.0)下的涡激振动模式。而涡激振动模式在不同的间距比条件下又具有单锁定区间(P/D=1.6)和双锁定区间(P/D=2.5~4.0)两种不同振动特征。进一步分析尾流模式,发现第一锁定区间(含单锁定区间)内的振动响应由剪切层重附着机制激发,而第二锁定区间内的振动响应由交替尾涡泄放机制激发。The flow-induced vibration of three rigidly coupled cylinders was numerically investigated by using the iterative immersed boundary method.The three cylinders are in equilateral-triangular arrangements,two side-by-side cylinders upstream and one cylinder downstream.The spacing ratio of the cylinders is P/D=1.0-4.0,the Reynolds number is Re=100,the mass ratio is m=2,and the reduced velocity is U_(r)=3-30.Variations of the vibration amplitude,the vibration frequency and the hydrodynamic forces of the cylinders with the reduced velocity were investigated.Two vibration modes were found,and they are the galloping mode at a small spacing ratio(P/D=1.0)and the vortex-induced vibration mode at a medium and large spacing ratio(P/D=1.6-4.0).Under the conditions with different spacing ratios,the vortex-induced vibration shows distinct features,i.e.the single lock-in region at P/D=1.6 and double lock-in regions at P/D=2.5-4.0.By further investigating the wake patterns,it was found that in the first lock-in region(also in the single lock-in region),the vibration is excited by the shear-layer reattachment,while in the second lock-in region,the vibration is provoked by the alternate vortex-shedding from the cylinders.

关 键 词：刚性耦合 三圆柱 流致振动 等边三角形排列 

分 类 号：P751[交通运输工程—港口、海岸及近海工程] TB531[天文地球—海洋科学]