氢气泡DPIV技术在圆柱绕流流场测定中的应用

Application of hydrogen bubble DPIV technique in measurement of flow field around a circular cylinder

将氢泡示踪法与数字图像分析技术结合,设计了一套粒子图像流场观测装置,对不同雷诺数下的圆柱绕流流场进行了观测。实验中清晰观察到圆柱绕流的卡门涡街现象。采用基于互相关算法的分析软件对图像进行处理,得到流速矢量图、等值线图及涡量图。根据图像及计算结果,分析了一个拟周期内圆柱后涡旋的发展、演化过程。实测结果表明,随着雷诺数的增大,圆柱绕流近尾迹区长度逐渐缩短。将流动特性实测结果与相关文献进行了对比,结果基本一致。

A particle image flow field observation system was designed to observe flow around a cylinder underdifferent Reynolds number by combining hydrogen bubble tracer method and DPIV technique. Karman vortex streetphenomenon was clearly observed from the images. Velocity vector, contour maps and vorticity graph were obtainedby the software based on covariant-analysis algorithm. The vortex development around the cylinder in a pseudo-peri-od was discussed according to the images and calculation results. Experiment results show that the length of wakezone gradually shrinks with increasing Reynolds number. The experimental results of flow characteristics are basi-cally consistent with the published results of measurements by other methods.