二维翼型非定常运动的涡流场显示--2俯仰运动和沉浮/俯仰联合运动

介绍了在水洞中进行的二维机翼纯俯仰运动和沉浮/俯仰联合运动时的流动显示实验.实验结果揭示了机翼做纯俯仰运动时尾迹涡街的特性以及与Strouhal数(Ste)的关系.在Ste=0.105附近,涡街排列成一条线;大于该值,为逆Karman涡街;小于该值,为正Karman涡街.机翼做沉浮/俯仰联合运动时,尾迹中总是出现逆Karman涡街.结合数值计算结果说明,机翼做沉浮/俯仰联合运动时,推力及最大有效迎角与沉浮和俯仰运动之间的相位差有关.并讨论了前缘涡与后缘涡相互作用对推力的影响.

The visualization of vortex field of unsteady motion for 2 - D airfoil--2 pitching motion and heaving/pitching composite motion

An experiment on the visualization of vortex field produced by a 2-D airfoil with pitching motion and composite motion of heaving and pitching was conducted in a water tunnel. The experimental results revealed that for the airfoils with pitching motion the characteristic of vortex street depended on Strouhal number (Ste), in which the vortex street arranging in a line occurred when Ste=0.105, reverse Karman vortex street for Ste>0.105 and Karman vortex street for Ste<0.105. The results also showed that Karman vortex street has always reverse when the airfoil moved with heaving and pitching. The results of the numerical calculation showed that the thrust and the maximum effective attack angle were related to the phase difference between heaving and pitching. Influence of the interaction between leading-edge vortex and trailing-edge vortex on the propulsion was also discussed.