应用PIV系统研究横流中水平方柱绕流旋涡特征

Research on vortices of cross flow past a horizontal square cylinder by PIV system

利用PIV系统对二维水平方柱绕流的旋涡特性进行了试验研究,得到了来流雷诺数为796-9 556、不同间隙比(G=3.0,1.0,0.2)时方柱绕流瞬时流场分布.根据这些数据,分析了方柱绕流流场中旋涡发展和演化规律,比较了瞬时流场和时均流场中旋涡结构特征,给出了不同工况下分离区长度L及斯特罗哈数St与雷诺数的关系.

The experimental research of vortices characteristic of flow past a two-dimensional horizontal square cylinder is conducted by PIV（particle image velocimetry） systems the instantaneous velocity distribution of the whole field is obtained under the conditions of Reynolds number range of 796 to 9556 and several gap-ratios （G=3.0, 1.0, 0.2）. Based on these data, the regularity of vortex formation, development and shedding in the wake is analyzed. Both the instantaneous and time-average vortices characteristics of the field are compared. Finally, the relationship of separated-length and Strouhal number with Reynolds number in different conditions is given.