再附着剪切层中的大涡结构  

Large Eddy Structure in Shear Layer With Reattachment

作　　者：周慧良[1] 许经民[1] 曹伟 沈育毅 

机构地区：[1]复旦大学应用力学系

出　　处：《水动力学研究与进展（A辑）》1990年第1期23-29,共7页Chinese Journal of Hydrodynamics

摘　　要：在空气流动中利用流场显示技术对二维后向台阶流动的分离和再附着剪切层中的大涡结构作了实验研究。发现当分离前为层流边界层时,分离后有一平直段,其长度随来流速度和台阶高度的增大而缩短。剪切层的发展受层中大涡支配,涡脱落频率随来流速度的提高而加快。在再附着点之前有涡的归并现象出现。再附着长度与台阶高度的比值仅与来流速度有关。再附着点附近涡的尺度与台阶高度相当。大涡碰壁后有时被撕裂成两个,有时被撞碎,有时弹离壁面向下游运动。流动很不规则,难以预测。The experimental studies for large eddy structures in reattached shear layer over two-dimensional backward-facing step flow are made with flow visualization techniques. The main items are the movement of the reattached shear layer and the vortices nearby the reattachment point. A qualitative analysis of the flow pattern is made using a video camera and photographs. Also, some results such as the stable length in shear layer, the vortex shedding frequency and the reattachment are given quantitatively by the video cassette.

关 键 词：流动显示 涡结构 剪切层 涡脱落 湍流 

分 类 号：O357.52[理学—流体力学]