间距比对近壁串列双圆柱绕流影响的实验研究  

Effect of Spacing Ratio on Flow Passed Two Circular Cylinders in Tandem Arrangements Near Wall Via Experiment

作　　者：邓勇[1] 尹广洲 周磊 喜冠南[1] DENG Yong;YIN Guang-zhou;ZHOU Lei;XI Guan-nan(School of Mechanical Engineering,Nantong University,Jiangsu Nantong 226019,China)

机构地区：[1]南通大学机械工程学院,江苏南通226019

出　　处：《机械设计与制造》2022年第10期174-177,181,共5页Machinery Design & Manufacture

基　　金：国家自然科学基金—过渡流下分离与再附不稳定性及其传热强化机理(51476080)。

摘　　要：这里基于圆柱绕流循环水槽实验台,结合粒子图像测速系统,对壁面边界层层流区域插入串列双圆柱模型进行了实验研究。通过改变横向间距比,结合速度流线、速度截面以及周期性对圆柱尾流和壁面附近流动不稳定性进行分析。结果表明:Re=200时,横向间距比对圆柱尾流与壁面附近流动不稳定性影响显著。圆柱绕流结构方面:随着横向间距比的增加,两圆柱间由封闭流动转变为非封闭流动,圆柱间旋涡对尺度先增大后减小至稳定,下游圆柱由旋涡对演变为上游剪切层单向绕流。壁面扰动方面:随着横向间距比的增加,上游圆柱下剪切层加速效应增加,圆柱间近壁区域流动不稳定性增强;下游圆柱下剪切层加速效应减弱,近壁区域流速减小,导致下游壁面涡导逐渐消失,壁面流动不稳定性减弱。在过渡流状态下,近壁串列双圆柱尾流形成周期性的交替旋涡脱落,增强了壁面附近的流动不稳定性。The experimental study on two circular cylinders in tandem arrangements which insert into the laminar region of the wall boundary layer is carried out.An open-loop recirculating water tunnel was set up,and the velocity field is obtained by particle image velocimetry(PIV).The flow instability of the cylindrical wake and the wall are analyzed by changing the transverse spacing ratio,combining with the velocity streamline,velocity in cross section and periodicity.Results show that:the transverse spacing ratio has a significant effect on the flow instability of the cylindrical wake and the wall as Re=200.The flow structure of the cylinder:as the ratio of the lateral spacing increases,the two cylinders change from a closed flow to a non-closed flow.The inter-column vortex increases first and then decreases to a stable state,and the downstream cylinder evolves from a vortex pair to The upstream shear layer is independently flowed.The wall flow instability:as the lateral spacing ratio increases,the acceleration of the downstream separation shear layer of the upstream cylinder increases,the fluid instability in the near wall region between the cylinders increases;The acceleration effect of the separation shear layer downstream of the downstream cylinder is weakened,and the flow velocity in the near wall region decreases.As a result,The vortex on the downstream wall gradually disappears,and the wall flow instability is weakened.Under the transitional flow,the near-wall tandem double cylinder wakes form periodic alternating vortex shedding,which enhances the flow instability near the wall surface.

关 键 词：流动不稳定性 粒子图像测速 近壁串列双圆柱 横向间距比 

分 类 号：TH16[机械工程—机械制造及自动化] TK124[动力工程及工程热物理—工程热物理]