摘要
翼型俯仰过程中流动结构演化复杂,呈现为多种类型涡之间的相互作用。基于时变粒子图像测速技术(Time Resolved Particle Image Velocimetry,TR-PIV),对雷诺数Re=3.0×10^(5),减缩频率k=0.03条件下,俯仰翼型近壁面流动结构的时空演化进行定量研究。分析结果表明:在上仰和下俯阶段的相同攻角下,下俯阶段的分离点位置更靠近前缘,剪切层不稳定性强于上仰阶段,这种差异与前缘壁面法向速度相对于来流的速度有关;下俯阶段,流场中观察到了沿着吸力面向后缘发展的逆时针旋转二次涡,二次涡促进了顺时针旋转的展向涡脱落,并与展向涡融合,使流场发生剧烈变化;上仰阶段,观察到前缘涡(Leading-edge Vortex,LEV)和剪切层涡(Shear Layer Vortex,SLV)2种不同类型的涡结构,两者在空间位置、结构形态、输运速度等方面存在差异,但也存在联系,剪切层涡促进了前缘涡的发展,前缘涡之间的相互融合形成了大尺度的动态失速涡(Dynamic Stall Vortex,DSV),动态失速涡的发展也受剪切层涡的影响。
The evolution of the pitching airfoil flow structure is complex,exhibiting interactions between various vortices.Based on TR-PIV(Time Resolved Particle Image Velocimetry),the spatio-temporal evolution of the flow structures on the near-wall surface of a pitching airfoil is quantitatively investigated under the conditions of Reynolds number is 3.0×10^(5) and reduced frequency is 0.03.At the same angles of attack of upstroke and downstroke,the separation point is closer to the leading edge and the shear layer instability is more intense on the downstroke.This discrepancy is related to wall-normal component of velocity at the leading edge,relative to that of the incident flow.On the downstroke,the secondary counter-rotating vortex develops towards the trailing edge along the suction surface are observed in the flow field.The secondary vortex promotes the spanwise vortex shedding and merges with the spanwise vortex,causing violent changes in the flow field.On the upstroke,two types of vortex,leading-edge vortex and shear layer vortex are observed,with differences in spatial location,structural morphology,convective velocity,etc.However,there is also a connection between them,as the shear layer vortex promotes the development of the leading-edge vortex,the merging between the leading-edge vortices forms large-scale dynamic stall vortex,and the development of the dynamic stall vortex is also influenced by the shear layer vortex.
作者
陈吉风
张传鸿
彭傲雪
史志伟
CHENG Jifeng;ZHANG Chuanhong;PENG Aoxue;SHI Zhiwei(College of Aerospace Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing Jiangsu 210016,China;MIIT Key Laboratory of Unsteady Aerodynamics and Flow Control,Nanjing Jiangsu 210016,China)
出处
《海军航空大学学报》
2024年第4期492-500,共9页
Journal of Naval Aviation University
基金
江苏高校优势学科建设工程(PAPD)。
关键词
俯仰翼型
二次涡
剪切层涡
前缘涡
动态失速涡
pitching airfoil
secondary vortex
shear layer vortex
leading-edge vortex
dynamic stall vortex
