| Tomographic TR-PIV measurement of coherent structure spatial topology utilizing an improved quadrant splitting method | |
Yang SQ; Jiang N(姜楠) ; Jiang, N; Tianjin Univ, Sch Mech Engn, Dept Mech, Tianjin 300072, Peoples R China.
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| Source Publication | SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY
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| 2012-10-01 | |
| Volume | 55Issue:10Pages:1863-1872 |
| ISSN | 1674-7348 |
| Abstract | In this paper, we calculated the spatial local-averaged velocity strains along the streamwise direction at four spatial scales according to the concept of spatial local-averaged velocity structure function by using the three-dimensional three-component database of time series of velocity vector field in the turbulent boundary layer measured by tomographic time-resolved particle image velocimetry. An improved quadrant splitting method, based on the spatial local-averaged velocity strains together with a new conditional sampling phase average technique, was introduced as a criterion to detect the coherent structure topology. Furthermore, we used them to detect and extract the spatial topologies of fluctuating velocity and fluctuating vorticity whose center is a strong second-quadrant event (Q2) or a fourth-quadrant event (Q4). Results illustrate that a closer similarity of the multi-scale coherent structures is present in the wall-normal direction, compared to the one in the other two directions. The relationship among such topological coherent structures and Reynolds stress bursting events, as well as the fluctuating vorticity was discussed. When other burst events are surveyed (the first-quadrant event Q1 and the third-quadrant event Q3), a fascinating bursting period circularly occurs: Q4-S-Q2-Q3-Q2-Q1-Q4-S-Q2-Q3-Q2-Q1 in the center of such topological structures along the streamwise direction. In addition, the probability of the Q2 bursting event occurrence is slightly higher than that of the Q4 event occurrence. The spatial instable singularity that almost simultaneously appears together with typical Q2 or Q4 events has been observed, which is the main character of the mutual induction mechanism and vortex auto-generation mechanism explaining how the turbulence is produced and maintained. |
| Keyword | Turbulent Boundary Layer Coherent Structure Burst Tr-piv Q2/q4 Local-averaged Velocity Strain Quadrant Splitting Method Turbulent-boundary-layer Wall Turbulence Motions Scale Flows |
| Subject Area | 湍流 |
| URL | 查看原文 |
| Indexed By | SCI ; EI |
| Language | 英语 |
| WOS ID | WOS:000308953800020 |
| Funding Organization | This work was supported by the National Basic Research Program of China (Grant No. 2012CB720101), the National Natural Science Foundation of China (Grant No. 10832001) and the Opening Subject of State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences. The authors are most grateful to the DLR Institute of Aerodynamics and Flow Technology for providing the tomographic TR-PIV database of time series of velocity vector field as well as the guidance and assistance of experimental technology for the present work. |
| Classification | 二类/Q3 |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://dspace.imech.ac.cn/handle/311007/46738 |
| Collection | 非线性力学国家重点实验室 |
| Corresponding Author | Jiang, N; Tianjin Univ, Sch Mech Engn, Dept Mech, Tianjin 300072, Peoples R China. |
| Recommended Citation GB/T 7714 | Yang SQ,Jiang N,Jiang, N,et al. Tomographic TR-PIV measurement of coherent structure spatial topology utilizing an improved quadrant splitting method[J]. SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY,2012,55,10,:1863-1872. |
| APA | Yang SQ,姜楠,Jiang, N,&Tianjin Univ, Sch Mech Engn, Dept Mech, Tianjin 300072, Peoples R China..(2012).Tomographic TR-PIV measurement of coherent structure spatial topology utilizing an improved quadrant splitting method.SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY,55(10),1863-1872. |
| MLA | Yang SQ,et al."Tomographic TR-PIV measurement of coherent structure spatial topology utilizing an improved quadrant splitting method".SCIENCE CHINA-PHYSICS MECHANICS & ASTRONOMY 55.10(2012):1863-1872. |
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