三棱柱尺度比对尾流场的影响  

Effect of aspect ratio of a triangular prism on wake field

作　　者：江裕荣 江建华 鲍锋 JIANG Yurong;JIANG Jianhua;BAO Feng(School of Aeronautics and Astronautics,Xiamen University,Xiamen 361005,China)

机构地区：[1]厦门大学航空航天学院

出　　处：《空气动力学学报》2019年第6期901-907,共7页Acta Aerodynamica Sinica

基　　金：国家自然科学基金面上项目（11072206）;福建省科学基金（2012J01023）

摘　　要：应用粒子成像测速技术(Particle Image Velocimetry,PIV)对不同柱体截面尺度比H(H=3.8、1.9、1.2、0.9、0.7)的三棱柱在雷诺数Re=500条件下的尾流场进行定量测量。对尾流场进行定常和非定常分析,同时结合本征正交分解法和时间空间关联法,研究尺度比H对尾流场相干结构以及尾流场中涡街稳定运输区和涡街流向运输速率的影响。研究发现,三棱柱尺度比H的减小对尾流宽度、尾涡形成长度都有明显的促进作用,但旋涡脱落变慢,非定常性变弱。分析各阶模态对湍动能的贡献,发现随着尺度比H的减小,高阶模态湍动能占比之和有所增加。这就导致尾流场愈加不稳定,涡街稳定运输区域、涡街流向输运速率均减小。同时尾流宽度增大,尾流场阻力系数C D增大。The wake field of a triangular prism is studied quantitatively in this paper by using particle image velocimetry(PIV)measurement,with different aspect ratios H(H=3.8,1.9,1.2,0.9,and 0.7)at a Reynolds number Re=500.On the basis of steady and unsteady analyses,proper orthogonal decomposition(POD)and time-space cross correlation method are performed to analyse the influence of aspect ratios H on the coherent structure of the wake field,the steady-state transport zone,and vortex streamwise transport rate.The results show that,an increase in the width of the wake flow and the length of the wake vortex is generally related to a decrease in aspect ratio H,leading to vortex shedding slowing down and the unsteadiness of wake field weakening.A POD was performed to analysis the contribution of each mode on turbulent kinetic energy.It was found that the sum of high-order modal kinetic energy increased at low aspect ratio H with unstable wake field,decreased the steady-state transport zone and vortex streamwise transport rate.As a result,drag force coefficient increased with the increase in the width of the wake flow.

关 键 词：三棱柱柱体 尺度比 粒子成像测速 尾流场 本征正交分解 时间空间关联 

分 类 号：V211.76[航空宇航科学与技术—航空宇航推进理论与工程]