过渡流下近壁双圆柱倾角对绕流结构影响  

Influence of two near-wall cylinders with different angles on flow structure in transitional flow

作　　者：尹广洲 邓勇[1] 周磊 谢纬安 喜冠南[1] YIN Guangzhou;DENG Yong;ZHOU Lei;XIE Weian;XI Guannan(School of Mechanical Engineering, Nantong University, Nantong, Jiangsu 226019, China;School of Automotive and Traffic Engineering, Nantong Vocational University, Nantong, Jiangsu 226007, China)

机构地区：[1]南通大学机械工程学院,江苏南通226019 [2]南通职业大学汽车与交通工程学院,江苏南通226007

出　　处：《排灌机械工程学报》2021年第11期1118-1124,共7页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(51476080);南通市基础科学研究计划项目(JC2018079)。

摘　　要：为了研究过渡流下近壁双圆柱倾角对绕流结构的影响,在雷诺数为300(基于圆柱直径D=15 mm)时,采用开式循环水槽试验台,结合粒子图像测速系统PIV对不同倾角的近壁双圆柱模型进行了试验研究.结果表明:当Re为300时,倾角γ改变对圆柱绕流结构影响显著.随着倾角γ增大,上游圆柱尾流由下侧剪切层发展被抑制逐渐演变为上侧剪切层发展被抑制,上游近壁区域加速效果先增强后减弱;下游圆柱尾流由上侧剪切层主导逐渐演变为下侧剪切层主导,下游近壁区域的加速效果和范围不断增大至稳定.当γ<7.6°时,倾角γ对绕流结构影响逐渐增大,近壁区域扰动逐渐增强;当γ>7.6°时,倾角γ对绕流结构影响逐渐减弱,近壁区域扰动趋于稳定.详细分析了γ=-7.6°工况下的瞬时流动特性,发现近壁双圆柱尾流形成周期性的旋涡交替脱落现象,增强了壁面附近流动不稳定性.In order to investigate the influence of the two near-wall cylinders with different angles on the flow structure in transitional flow,this model based on the cylinder diameter D=15mm with Rey-nolds number 300 was calculated.Flow visualization experiments with the particle image velocimetry(PIV)system were conducted based on the open-loop fluid test bench.The results show that when Re number is 300,the angleγof the two near-wall cylinders has a significant effect on the flow structure around the cylinder.The upstream cylindrical wake is suppressed with the increase of the angleγ,where the upper side is suppressed and then the lower side is suppressed and the acceleration effect of the upstream near-wall region first increases and then decreases.The downstream cylindrical wake is mainly affected from the upstream shear layer to the downstream shear layer with the increase of the angleγ.Also,the magnitude and regions of the acceleration effect increase and then stabilize in the near-wall area.The influence of the angleγon the flow structure is gradually increased and the disturbance in the near-wall area is gradually enhanced within the cases ofγ<7.6°.The influence of the angleγon the flow structure is gradually weakened and the range of fluid disturbance tends to be stable within the cases ofγ>7.6°.The transient flow characteristics were analyzed in detail for the case ofγ=-7.6°.It is found that the periodic vortex shedding phenomenon is formed in the wake of two near-wall cylinders,which enhances the flow instability of the wall.

关 键 词：过渡流 近壁 流动结构 双圆柱倾角 粒子图像测速 

分 类 号：S277.9[农业科学—农业水土工程]