A visualization study of the instantaneous flow patterns in a laminar junction flow is presented in the paper. The pulsed hydrogen bubble technique and video recording system allows the recording of instantaneous flow field in the present study. The arrangement of the hydrogen bubble wire was proven to be critical for revealing the fine structure of the junction flow. The junction flows produced by a rectangular block extending from the surface were tested with Reynolds number ranging from Reδ* = 2.74 × 102 to 3.19 × 102. The results illustrate the existence of primary horseshoe vortices and counter-rotating secondary vortices. Some new features, such as the behavior of the head portion of a primary HV in the formation region and its shoulders upstream of the block, were found in the visualization study.%对层流角区流动的动态流动模式进行了流动可视化实验研究.实验采用了脉冲氢泡发生器和录像系统对流场进行了显示和研究.通过实验发现,氢泡丝的布置是清晰显示角区流动的精细结构的重要因素.实验雷诺数范围为Reδ*=2.74×102～3.19×102.该实验的角区流动由在平板表面的长方形突起物产生.实验结果显示了主马蹄涡和反向二次涡的流动结构和流动过程.实验还发现了一系列新的流动现象,如马蹄涡的头部形成区域的流动过程及其在柱体上游形成"肩膀"的现象等.
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