单/双自由度旋转圆柱流致振动特性数值计算分析  

One degree and two degrees of freedom flow-induced vibration of circular cylinders

作　　者：包燕旭 张小玉[1] 陈威[2] 林永水[1] 李晓彬[2] BAO Yan-xu;ZHANG Xiao-yu;CHEN Wei;LIN Yong-shui;LI Xiao-bin(School of Science,Ocean and Energy Power Engineering,Wuhan University of Technology,Wuhan 430063,China;School of Naval Architecture,Ocean and Energy Power Engineering,Wuhan University of Technology,Wuhan 430063,China)

机构地区：[1]武汉理工大学理学院,武汉430063 [2]武汉理工大学船海与能源动力工程学院,武汉430063

出　　处：《船舶力学》2023年第11期1661-1670,共10页Journal of Ship Mechanics

基　　金：湖北省自然科学基金项目(2021CFB064);国家自然科学基金资助项目(51979213;52201334)。

摘　　要：为探讨不同自由度下旋转圆柱流致振动特性,本文对单/双自由度二维旋转圆柱在不同转速比下的流致振动进行了数值模拟研究,分析并对比了不同自由度下漩涡脱落模式及分布区间、流体力、振幅响应。研究时观察到六种脱涡模式,单自由度四种(2S,P+S,2P,U),双自由度五种(2S,P+S,P+T,2T,U),单自由度下U模式区间更大,双自由度下在较高转速比及约化速度下易呈现多涡模式(P+T、2T)。研究结果显示:对于1-DOF圆柱,振幅峰值随转速比增加而增大,锁定区间随旋转比增加而加宽,且在(α=3,Vr=11)时发生跳跃,此时脱涡模式由2S变为2P;对于2-DOF圆柱,无旋转下顺流向自由度促进横流向振动,横流向振幅峰值较1-DOF更大;在转速较小(α=1)时,横流向振幅峰值较无旋转更小,锁定区间缩短,表明低速旋转下顺流向自由度抑制横流向振动;对于较高转速比(α=2,3),圆柱振幅响应发生多次跳跃,每次跳跃峰值递增,并伴随脱涡模式改变(脱涡数增多,脱涡大小、涡量及尾流结构的对称性降低);双自由度下圆柱运动轨迹从8字形逐渐变为窄椭圆形,最终变为大回环扁椭圆形运动。解放顺流向自由度促进了横流向振动,引起了尾流结构的复杂化和圆柱振幅响应的多次跳跃。To study the characteristics of flow-induced vibration(FIV)responses of a rotating circular cylin-der for different degrees of freedom,two-dimensional numerical simulations of one-degree-of-freedom(1-DOF)and two-degrees-of-freedom(2-DOF)of rotating cylinder were investigated,and the wake patterns and their distributions,hydrodynamics and vibration responses for different degrees of freedom were analyzed and compared in this parer.The results show that,among the six wake patterns observed,there are four pat-terns(2S,P+S,2P,U)for 1-DOF and five patterns(2S,P+S,P+T,2T,U)for 2-DOF with the U pattern re-gion larger for 1-DOF.The wake shows multiple vortex patterns(P+T,2T)at higher rotation rates and re-duced velocities for 2-DOF.1-DOF maximum amplitude increases while the lock-in interval widens with the increasing rotation rate.The amplitude jumps at(α=3,Vr=11),and the wake pattern changes from 2S to 2P.For 2-DOF,the in-line degree of freedom promotes cross-flow vibration at no rotation,and the peak cross-flow amplitude is higher than for 1-DOF.At lower rotation rates(α=1),the peak cross-flow amplitude is smaller than that without rotation and the lock-in interval is shorter,indicating that cross-flow vibration is suppressed by the in-line degree-of-freedom at lower rotation rates.At higher rotation rates(α=2,3),the cy-lindrical amplitude response undergoes multiple jumps,the amplitude reaches a higher peak in every jump and is accompanied by a change in the wake pattern(the number of vortices increases,the size and vorticity of the vortices and the symmetry of the wake decrease).The 2-DOF cylindrical trajectory changes from a“8”shape,gradually to a narrow elliptical-like one and eventually to a large circular elliptical-like one.The in-line degree-of-freedom promotes cross-flow vibrations,complicates the wake structure and causes multiple jumps in the cylindrical amplitude response.

关 键 词：旋转比 圆柱绕流 流致振动 脱涡模式 流固耦合 

分 类 号：O352[理学—流体力学]