Experimental investigation on coherent structures at early stage of boundary layer bypass transition induced by wake impingement

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	Experimental investigation on coherent structures at early stage of boundary layer bypass transition induced by wake impingement
其他题名	Experimental investigation on coherent structures at early stage of boundary layer bypass transition induced by wake impingement
	Wu Jun 1; Pan Chong 1; Li Tian 1
	2012
发表期刊	SCIENCE CHINA-TECHNOLOGICAL SCIENCES
ISSN	1674-7321
卷号	55 期号:11 页码:2981-2989
摘要	The early stage of a boundary layer bypass transition induced by the direct impingement of a circular cylinder wake is experimentally investigated in water tunnel, with the primary interest in both the evolution of coherent structures and their effects on the disturbance growth inside the boundary layer. It is found that spanwise vortices with small scale first form in the near-wall region around the leading-edge, which are either the residual of the wake rollers cut by the leading-edge or the high-order structures induced by the wake rollers. The formation of these spanwise vortices leads to the first rapid disturbance growth inside the boundary layer. On the other hand, streamwise vortices, which result from the impingement of longitudinal braids onto the leading-edge, are also observed inside the boundary layer. They lead to the three dimensional destabilization and the subsequent dispersion of spanwise vortices, and soon become the most dominant coherent structures inside the transitional boundary layer. It is suggested that the formation and evolution of these streamwise vortices contribute to the secondary disturbance growth stage and thus promote the completion of the transition process. The difference between the present transition scenario triggered by direct wake impingement and that by indirect wake-vortex inducement is further discussed.
其他摘要	The early stage of a boundary layer bypass transition induced by the direct impingement of a circular cylinder wake is experimentally investigated in water tunnel,with the primary interest in both the evolution of coherent structures and their effects on the disturbance growth inside the boundary layer.It is found that spanwise vortices with small scale first form in the near-wall region around the leading-edge,which are either the residual of the wake rollers cut by the leading-edge or the high-order structures induced by the wake rollers.The formation of these spanwise vortices leads to the first rapid disturbance growth inside the boundary layer.On the other hand,streamwise vortices,which result from the impingement of longitudinal braids onto the leading-edge,are also observed inside the boundary layer.They lead to the three dimensional destabilization and the subsequent dispersion of spanwise vortices,and soon become the most dominant coherent structures inside the transitional boundary layer.It is suggested that the formation and evolution of these streamwise vortices contribute to the secondary disturbance growth stage and thus promote the completion of the transition process.The difference between the present transition scenario triggered by direct wake impingement and that by indirect wake-vortex inducement is further discussed.
关键词	CYLINDER WAKE VORTEX RING DISTURBANCES VORTICITY FLOW WALL circular cylinder wake flat-plate boundary layer bypass transition coherent structures
收录类别	CSCD
语种	英语
资助项目	[National Natural Science Foundation of China]
CSCD记录号	CSCD:4717098
引用统计
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/142970
专题	中国科学院金属研究所
作者单位	1.上海市地震局 2.中国科学院金属研究所
推荐引用方式 GB/T 7714	Wu Jun,Pan Chong,Li Tian. Experimental investigation on coherent structures at early stage of boundary layer bypass transition induced by wake impingement[J]. SCIENCE CHINA-TECHNOLOGICAL SCIENCES,2012,55(11):2981-2989.
APA	Wu Jun,Pan Chong,&Li Tian.(2012).Experimental investigation on coherent structures at early stage of boundary layer bypass transition induced by wake impingement.SCIENCE CHINA-TECHNOLOGICAL SCIENCES,55(11),2981-2989.
MLA	Wu Jun,et al."Experimental investigation on coherent structures at early stage of boundary layer bypass transition induced by wake impingement".SCIENCE CHINA-TECHNOLOGICAL SCIENCES 55.11(2012):2981-2989.