圆柱体绕流尾迹的PIV测量

Measurements of cylinder's wake by PIV

PIV是一种先进的流场定量测量技术,在生产性风洞中的应用前景非常广泛。利用PIV测量技术,采用双CCD摄像机在FL-5低速生产性风洞中对不同的雷诺数Re下圆柱体绕流尾迹进行定量的测量,给出了圆柱体绕流尾迹的瞬时速度场、涡量场和流场的流线图。通过测量发现剪切层的相互作用是圆柱体绕流尾迹区旋涡形成和脱落的重要因素,并直接验证了Gerrard的绕流尾迹理论;在雷诺数Re=104～105范围内,随着雷诺数的增大圆柱绕流近尾迹区旋涡形成区域长度在逐渐缩短。

PIV is an advanced quantitative measurement technology for flow dynamics or flow structures, and will be used broadly in productive wind tunnel. This paper describes the measurement of cylinder's wake flow of different Reynolds number in FL-5 low speed wind tunnel using PIV with double-CCD cameras, and shows instantaneous velocimetry vector and vortex distribution map and stream map of cylinder's wake. From PIV measurement results, we find that the important reason of vortex forming and shedding of cylinder's wake region is the interactional effect of shear layer, and directly verifies the theory of Gerrard about cylinder's wake. In the range of Re=10~4～10~5, with Reynolds number increasing, the length of vortex forming region of cylinder's wake gradually shortens.