翼型近尾迹流动的PIV研究——动力学机制

PIV STUDY OF AIRFOIL NEAR WAKE FLOW PARTⅡ DYNAMIC MECHANISM

利用在线式互相关ＰＩＶ（ＰａｒｔｉｃｌｅＩｍａｇｅＶｅｌｏｃｉｍｅｔｒｙ）系统，在低速风洞中对ＮＡＣＡ００１２翼型在雷诺数２．３９×１０５，０°和４°攻角下的近尾迹流动进行了详细测量。实验结果表明，翼型近尾迹存在有序的涡街结构，涡街在尾缘处形成后，在向下游的迁移中，会经历一个发展壮大、失稳破碎的演化过程，流动从有序走向无序。翼型的近尾迹是一种以旋涡的运动学特性和动力学机制为主导的流动现象。本文着重探讨了翼型尾缘处的涡街形成机理，尾迹内的流动机制，以及近尾迹的流动稳定性。

Detailed 2D velocity and vorticity fields were measured to investigate the turbulent near wake flow of NACA0012 airfoil with on-line cross-correlation PIV in a low-speed wind tunnel.The Reynolds number on chord length is 2 39×10 5,the angles of attack are 0° and 4°.The experimental results indicate that ordered vortex streets exist in the turbulent near wake,the vortex streets created at the airfoil trailing edge region will fully develop and finally break up downstream,and the ordered wake flow turns into disordered.The near wake flow is dominated by the kinetic characteristics and dynamic mechanism of vortices.As the second part of the investigation,the paper mainly discusses the formation of the vortex streets,the dynamic mechanism of the near wake,and the fluid instability of the vortex and vortex streets.