小间距比下串列双圆柱涡激振动数值模拟研究:振动响应和流体力  

Numerical simulations for VIVs of two tandem cylinders with small spacing ratios:vibration responses and hydrodynamic forces

作　　者：陈威霖[1] 及春宁[1] 许栋[1] CHEN Weilin;JI Chunning;XU Dong(State Key Lab of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin300072,China)

机构地区：[1]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》2018年第23期261-269,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金创新研究群体科学基金(51621092);国家自然科学基金面上项目(51579175);国家超级计算广州中心支持

摘　　要：对小间距比(L*=1. 1～1. 5)下串列双圆柱涡激振动进行了数值模拟研究,其中Re=100,折合流速为U_r=3～30,质量比为m*=2. 0。为保证圆柱之间的距离不变,两圆柱均仅作横向振动。根据圆柱响应的不同将间距比范围内的涡激振动分为三种:(1)间距比L*≤1. 1时,响应存在于较大的折合流速(U_r=4～28)范围内;(2)间距比L*=1. 2～1. 3时,在大折合流速时,类似于高雷诺数时的尾流弛振出现;(3)间距比L*≥1. 5时,响应随折合流速增加并达到最大值,之后随折合流速缓慢减小,并最终稳定在较大的幅值上。对应不同的响应类型,上游和下游圆柱的流体力也呈现不同的变化;由于受到上游圆柱的屏蔽,下游圆柱的阻力均值要明显小于上游圆柱;在出现尾流弛振的区域,两圆柱的升力均方根随折合流速增加;此外,某些折合流速下圆柱之间的非稳定耦合作用也被反映出来。Numerical simulations for vortex-induced vibrations(VIVs)of two tandem cylinders with small spacing ratios of L^*=1.1-1.5were performed,where Reynolds number Re=100,the reduced flow velocity U r=3-30and the mass ratio m^*=2.0.Two cylinders only have transverse vibrations to keep the distance between them unchanged.The simulated results showed that there are three types of vibration responses;when L^*≤1.1,the responses exist in reduced flow velocity’s a larger range of U r=4-28;when L^*=1.2-1.3,wake relaxation vibration similar to VIV at high Re number appears under large reduced flow velocity;when L^*≥1.5,the vibration responses increase and reach the maximum with increase in reduced flow velocity,and then they decrease slowly and finally have a steady large value;the upstream and downstream cylinders’hydrodynamic forces have different changes for different types of vibration responses;the mean drag values of downstream cylinder are obviously lower than those of upstream cylinder due to the shielding effect of upstream cylinder;in the area where wake relaxation vibration appearing,the lift force’s mean square root values of two cylinders increase with increase in reduced flow velocity;the unsteady interactions between cylinders under some reduced flow velocities are revealed.

关 键 词：小间距比 串列双圆柱 涡激振动 振动响应 

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]