Three-dimensional structural characteristics of flow separation induced by a forward-facing step in a turbulent channel flow
文献类型：期刊论文
| 作者 | Fang, Xingjun3; Tachie, Mark F.3; Bergstrom, Donald J.2; Yang ZX(杨子轩)1; Wang, Bing-Chen3 |
| 刊名 | JOURNAL OF FLUID MECHANICS
 |
| 出版日期 | 2021-05-26 |
| 卷号 | 919页码:32 |
| 关键词 | boundary layer separation turbulent boundary layers |
| ISSN号 | 0022-1120 |
| DOI | 10.1017/jfm.2021.395 |
| 通讯作者 | Fang, Xingjun(fangx@myumanitoba.ca) |
| 英文摘要 | Separating and reattaching turbulent flows induced by a forward-facing step subjected to an incoming fully developed turbulent channel flow are studied using direct numerical simulation. The step height is one quarter of the channel height, and the Reynolds number based on friction velocity and half-channel height at the inlet is 180. The three-dimensional spatio-temporal characteristics of separation bubbles upstream and downstream of the step are analysed with particular attention to the effects of impinging hairpin structures and the topology of principal stretching. Immediately upstream of the step, the fluctuating vorticity parallel to the mean streamlines is significant. On the frontal surface of the step, strong spanwise skin friction appears in the form of alternating positive and negative values in vertical strips. Over the step, the principal stretching switches orientation along a curve emanating from the leading edge, which is termed the principal stretching line (PSL). The reverse flows upstream and downstream of the step possess dominant and harmonic frequencies that mirror those of the incoming flow. As a hairpin structure leans over the step, the associated vorticity is deformed by the principal stretching. Specifically, PSL marks the lower bound of the deformed hairpin legs, and an opposite-signed pair of counter-rotating quasi-streamwise vortices are induced near the top surface of the step. Consequently, the separation bubbles upstream of and over the step are enlarged and suppressed, respectively. For a sufficiently strong hairpin structure interacting with the step, an open-type separation occurs upstream of the step, while dual separation bubbles appear over the step. |
| 分类号 | 一类/力学重要期刊 |
| WOS关键词 | DIRECT NUMERICAL-SIMULATION ; LAMINAR BOUNDARY-LAYER ; LARGE-EDDY SIMULATION ; HAIRPIN VORTICES ; UNSTEADINESS ; DYNAMICS ; INSTABILITY ; TRANSITION ; UPSTREAM |
| 资助项目 | Natural Sciences and Engineering Research Council of Canada (NSERC)[RGPIN-2017-04957] |
| WOS研究方向 | Mechanics ; Physics |
| 语种 | 英语 |
| WOS记录号 | WOS:000654457800001 |
| 资助机构 | Natural Sciences and Engineering Research Council of Canada (NSERC) |
| 其他责任者 | Fang, Xingjun |
| 源URL | [http://dspace.imech.ac.cn/handle/311007/86783]  |
| 专题 | 力学研究所_非线性力学国家重点实验室 |
| 作者单位 | 1.Chinese Acad Sci, Inst Mech, Beijing 100190, Peoples R China 2.Univ Saskatchewan, Dept Mech Engn, Saskatoon, SK S7N 5A9, Canada; 3.Univ Manitoba, Dept Mech Engn, Winnipeg, MB R3T 5V6, Canada; |
| 推荐引用方式 GB/T 7714 | Fang, Xingjun,Tachie, Mark F.,Bergstrom, Donald J.,et al. Three-dimensional structural characteristics of flow separation induced by a forward-facing step in a turbulent channel flow[J]. JOURNAL OF FLUID MECHANICS,2021,919:32. |
| APA | Fang, Xingjun,Tachie, Mark F.,Bergstrom, Donald J.,杨子轩,&Wang, Bing-Chen.(2021).Three-dimensional structural characteristics of flow separation induced by a forward-facing step in a turbulent channel flow.JOURNAL OF FLUID MECHANICS,919,32. |
| MLA | Fang, Xingjun,et al."Three-dimensional structural characteristics of flow separation induced by a forward-facing step in a turbulent channel flow".JOURNAL OF FLUID MECHANICS 919(2021):32. |
入库方式： OAI收割
来源：力学研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。