非定常自由来流对二维翼型气动特性的影响研究  

The effects of unsteady free stream on the static and pitching airfoils

作　　者：史志伟[1] 明晓[1] 王同光[1] 

机构地区：[1]南京航空航天大学航空宇航学院,江苏南京210016

出　　处：《空气动力学学报》2008年第4期492-497,507,共7页Acta Aerodynamica Sinica

基　　金：直升机旋翼动力学重点实验室基金项目(51463030403HK0201)

摘　　要：利用计算软件和实验测量方法,研究了非定常自由来流对静态二维翼型气动特性的影响,分析研究了来流速度脉动频率变化对气动特性产生的作用。结果表明,来流速度以短周期脉动时,升力系数随来流速度的减小而增加;来流速度以长周期脉动时,升力系数随来流速度的减小而减小。分析表明这与前缘分离涡在翼面上的传递过程有关。又利用二维翼型动态实验台,研究了非定常自由来流对做动态运动的二维翼型气动特性的影响,结果表明,来流风速的脉动使升力系数的迟滞包线进一步扩大,最大升力系数增加。The unsteady aerodynamic responses of the stationary or dynamic NACA0012 airfoil in the oscillating free stream have been investigated through the FLUENT software and the experimental measurements of the dynamic pressure distributions. The effects of frequencies of velocity perturbation are discussed.The physical mechanisms behind those changes are analyzed. The test results of the stationary airfoil in oscillating free stream show that,in the short period of oscillating free-stream, the lift coefficients increase with decelerating. For the long period, the lift coefficients decrease with decelerating contrarily. These facts are related with the time scale of the vortex convection from the leading edge to the trailing edge and the externally time scale of velocity oscillating. The test data of the dynamic airfoil in oscillating free stream show that,the hysteresis loops of lift in coupled motion are enlargea. The maximum with the model pitching alone. The effects of oscillating free-stream appear significantly at the static stall angle of attack around,because the process of the leading-edge vortex convected from the leading edge becomes slowly when the free-stream velocity decelerates.

关 键 词：非定常自由来流 NACA0012翼型 俯仰运动 分离涡 

分 类 号：V211.7[航空宇航科学与技术—航空宇航推进理论与工程]