近壁面圆柱绕流中尾流结构演化特性的实验研究  

EXPERIMENTAL STUDY ON EVOLUTION OF WAKE STRUCTURES IN FLOW PAST THE CIRCULAR CYLINDER PLACED NEAR THE WALL

作　　者：邱翔 吴昊东 陶亦舟 李家骅 周建康 刘宇陆[4] Qiu Xiang;Wu Haodong;Tao Yizhou;Li Jiahua;Zhou Jiankang;Liu Yulu(School of Science,Shanghai Institute of Technology,Shanghai 201418,China;School of Mechanical Engineering,Shanghai Institute of Technology,Shanghai 201418,China;College of Urban Construction and Safety Engineering,Shanghai Institute of Technology,Shanghai 201418,China;Shanghai Institute of Applied Mathematics and Mechanics,School of Mechanics and Engineering Science,Shanghai University,Shanghai 200072,China)

机构地区：[1]上海应用技术大学理学院,上海201418 [2]上海应用技术大学机械工程学院,上海201418 [3]上海应用技术大学城市建设与安全工程学院,上海201418 [4]上海大学力学与工程科学学院,上海市应用数学和力学研究所,上海200072

出　　处：《力学学报》2022年第11期3042-3057,共16页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(12032016,91952102);上海市教育委员会“曙光计划”(18SG53)资助项目。

摘　　要：采用粒子图像测速技术对近壁面圆柱绕流流场进行了实验测量,重点研究了3种不同间隙比(G/D=0.5,G/D=1.0,G/D=1.5)时不同雷诺数(Re=1500~5540)下近壁面圆柱绕流尾流结构的演化特性.实验结果表明:G/D=0.5时,随着雷诺数的增加,间隙流的偏转减小,圆柱后方回流区逐渐对称且尺寸减小,壁面上分离泡的尺寸也逐渐减小,同时存在雷诺数Re_(t)位于Re=3000~3200之间,使圆柱尾流和间隙流呈现不同的分布特性,当雷诺数小于Re时,圆柱上游的壁面附近会形成一个小的分离泡,阻碍了上游流体通过间隙,使间隙流的强度减小,导致圆柱尾流和间隙流的偏转.在Re=1500时,圆柱的涡脱落频率随着间隙比的减小而增大,当Re≥3000时,随着间隙比减小,圆柱的涡脱落频率在小范围(0.185≤St≤0.227)内先增大后减小.雷诺数显著影响近壁面圆柱绕流涡结构的演化,小间隙比受雷诺数的影响较大,G/D=0.5,在雷诺数Re=1500时,二次涡会偏离壁面向上运动至靠近圆柱上尾涡位置处,与圆柱上尾涡发生涡合并现象,雷诺数增大到Re=5540时,二次涡不会和上尾涡合并,而是直接与下尾涡相互作用;G/D=1.0和G/D=1.5时,随着雷诺数的增大,二次涡的含能逐渐减小.The experimental measurement of the flow field around the circular cylinder near the wall is carried out by using the Particle Image Velocimetry.The characteristics of the flow regime under different Reynolds numbers(Re=1500~5540)together with three different gap ratios(G/D=0.5,G/D=1.0,G/D=1.5)are studied.The experiment results shows that for the case of G/D=0.5,with the increasing of Reynolds number,the recirculation zone behind the cylinder is gradually symmetrical about the centerline of the cylinder while its size is decreasing,and the size of the separation bubble on the wall also decreases gradually.The experiment reveals that the cylindrical wake and the gap flow perform differently while the Reynolds numbers Re_(t) between Re=3000~3200.When the Reynolds number is smaller than Re,a small separation bubble will form on the front wall of the cylinder,which hinders the flow of upstream fluid through the gap and reduces the intensity of the gap flow,and then deviates from the wall.At Re=1500,the vortex shedding frequency increases with the decrease of the gap ratio.And with the decrease of gap ratio,the vortex shedding frequency increases first and then decreases in a small range(0.185≤St≤0.227)for Re≥3000.The Reynolds number has a significant influence on the flow characteristics,especially for the case of small gap ratios.At G/D=0.5,the secondary vortex deviates from the wall and moves upward to the position close to the upper wake vortex,and the vortex merging process appears between the upper wake vortex and the secondary vortex for the Re=1500.As the Reynolds number increases to Re=5540,the secondary vortex does not merge with the upper wake vortex,and the secondary vortex directly interacts with the lower wake vortex.At G/D=1.0 and G/D=1.5,the energy carried by the secondary vortex is decreasing gradually with the increasing of Reynolds number.

关 键 词：粒子图像测速技术 圆柱绕流 近壁面 雷诺数 

分 类 号：O357.5[理学—流体力学]