壁面对串列双圆柱尾迹影响的实验研究  

Experimental Study of Wall Influence on the Wake Produced by Two Tandem Circular Cylinders

作　　者：陈波[1] 李万平[1] 

机构地区：[1]华中科技大学土木工程与力学学院,湖北武汉430074

出　　处：《实验力学》2011年第4期404-410,共7页Journal of Experimental Mechanics

基　　金：国家自然科学基金资助项目(10372033);西部灾害与环境力学教育部重点实验室开放基金资助

摘　　要：为研究壁面对近壁等直径串列双圆柱尾迹特性的影响,用PIV和压力传感器测量尾迹湍流的涡结构及频谱。实验在循环水槽内进行,基于圆柱直径D的雷诺数为1696,壁面边界层厚度为6.6D。影响尾迹流场结构的两个重要的特征参数是T/D和G/D(T为两圆柱中心间的距离,G为圆柱下表面与壁面间的距离),文中主要考察G/D的影响。实验中T/D=1.151;G/D=0.151～1.811。结果显示,G/D显著影响串列双圆柱的尾迹流场结构:当G/D=0.302时,尾迹开始出现大尺度涡脱落现象;当G/D=0.453～0.906时,随着G/D的增加,尾迹回流区域长度逐渐减小,涡脱落的强度和频率逐渐增加;当G/D≥1.057时,G/D的影响已经不明显,尾迹回流区域长度以及涡脱落频率几乎不变。相同G/D下,串列双圆柱T/D=1.151的尾迹回流区域长度小于单圆柱绕流的值;当G/D=0.302～0.755时,相同G/D下,串列双圆柱T/D=1.151的尾迹涡脱落频率小于单圆柱绕流的值,而当G/D=0.906～1.811时,串列双圆柱T/D=1.151的尾迹涡脱落频率大于单圆柱绕流的值。In order to investigate experimentally the flow characteristics of two tandem circular cylinders with equal diameter located in a fully developed turbulent boundary layer close to wall, the vortex structure in wake turbulent flow and frequency spectrum were measured by using particle image velocimetry （PIV） and pressure sensor. Experiment was performed in a recirculation water channel. Reynolds number is 1696 based on cylinder diameter （D） and the boundary layer thickness is 6.6D. Two significant parameters that influence the flowstructure in the experiment are T/D and G/D （T is the center-to-center spacing of two cylinders, G is the gap spacing between the cylinder lower surface and the wall）. The investigation is focused on the influence of G/D in this paper. In the experiment, T/D= 1. 151, and G/D=0. 151;1. 811. Results reveal that the wake flow characteristics are strongly dependent on G/D： when G/D = 0. 302, the large-scale vortex shedding begins in the wake; when G/D=0. 453;0. 906, the wake size decreases gradually, the vortex shedding becomes stronger and its frequency increases with increasing G/D; When G/D≥1. 057, the influence of G/D has becomes insignificant, and the wake size and vortex shedding frequency are almost unchanged as G/D increase. The recirculation region length for T/D= 1. 151 is shorter than that of a single cylinder for the same G/D; when G/D=0. 302;0. 755, for the same G/D, the frequency of vortex shedding for T/D=1. 151 is lower than that in the case of a single cylinder, but when G/D=0. 906;1. 811, the frequency of vortex shedding for T/D=1. 151 is higher than that in the case of a single cylinder.

关 键 词：近壁 串列双圆柱 PIV 尾迹 涡脱落 

分 类 号：O351.3[理学—流体力学] TV135[理学—力学]