低Reynolds数NACA0012翼型绕流的流动特性分析

在水槽中应用PIV测速技术研究了NACA0012翼型在Reynolds数为8200时的流动特性,重点关注了翼型绕流结构中主频和扰动增长速率随迎角的变化。结果表明,分离剪切层的扰动增长符合指数规律;且随着迎角的增大,转捩过程加速,表现为扰动增长率逐渐增大,转捩的起始位置逐渐向上游移动。在所有实验迎角情况下,流场均由脱落旋涡主导,但其主导作用随着迎角的增大而削弱。

Characteristic Analysis of Flow around NACA0012 Airfoil in a Low-Reynolds-number Media

Flow characteristics of NACA0012 airfoil at Reynolds number 8200 were experimentally investigated in a sink by using particle image velocimetry (PIV), focusing on the variation of main frequency and disturbance growth rate along with the attack angle's change(from 0° to 15°)in flow structure around airfoil. Results show that the separated shear layer disturbance grows exponentially at each attack angles. As attack angle increases, the transition process accelerates, perturbation growth rate increases, and the transition-onset point moves towards the leading-edge of airfoil. At each experimental attack angles, the flow field is dominated by vortex-shedding, and this dominance decreases along with the increase of attack angle.