| Experimental investigation on coherent structures at early stage of boundary layer bypass transition induced by wake impingement | |
| Alternative Title | Experimental investigation on coherent structures at early stage of boundary layer bypass transition induced by wake impingement |
| Wu Jun1; Pan Chong1; Li Tian1 | |
| 2012 | |
| Source Publication | SCIENCE CHINA-TECHNOLOGICAL SCIENCES
 |
| ISSN | 1674-7321 |
| Volume | 55Issue:11Pages:2981-2989 |
| Abstract | 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. |
| Other Abstract | 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. |
| Keyword | CYLINDER WAKE VORTEX RING DISTURBANCES VORTICITY FLOW WALL circular cylinder wake flat-plate boundary layer bypass transition coherent structures |
| Indexed By | CSCD |
| Language | 英语 |
| Funding Project | [National Natural Science Foundation of China] |
| CSCD ID | CSCD:4717098 |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/142970 |
| Collection | 中国科学院金属研究所 |
| Affiliation | 1.上海市地震局 2.中国科学院金属研究所 |
| Recommended Citation 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. |
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