| A study on coherent structures and drag-reduction in the wall turbulence with polymer additives by TRPIV | |
Guan XL; Yao SY; Jiang N(姜楠) ; Jiang, N (reprint author), Tianjin Key Lab Modern Engn Mech, Tianjin 300072, Peoples R China.
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| Source Publication | ACTA MECHANICA SINICA
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| 2013-08 | |
| Volume | 29Issue:4Pages:485-493 |
| ISSN | 0567-7718 |
| Abstract | An experimental measurement was performed using time-resolved particle image velocimetry (TRPIV) to investigate the spatial topological character of coherent structures in wall-bounded turbulence of polymer additive solution. The fully developed near-wall turbulent flow fields with and without polymer additives at the same Reynolds number were measured by TRPIV in a water channel. The comparisons of turbulent statistics confirm that due to viscoelastic structure of long-chain polymers, the wall-normal velocity fluctuation and Reynolds shear stress in the near-wall region are suppressed significantly. Furthermore, it is noted that such a behavior of polymers is closely related to the decease of the motion of the second and forth quadrants, i.e., the ejection and sweep events, in the near-wall region. The spatial topological mode of coherent structures during bursts has been extracted by the new mu-level criteria based on locally averaged velocity structure function. Although the general shapes of coherent structures are unchanged by polymer additives, the fluctuating velocity, velocity gradient, velocity strain rate and vorticity of coherent structures during burst events are suppressed in the polymer additive solution compared with that in water. The results show that due to the polymer additives the occurrence and intensity of coherent structures are suppressed, leading to drag reduction. |
| Keyword | Time-resolved Particle Image Velocimetry Wall-bounded Turbulence Coherent Structures Polymer Additives Drag Reduction |
| Subject Area | 湍流 |
| URL | 查看原文 |
| Indexed By | SCI ; EI ; CSCD |
| Language | 英语 |
| WOS ID | WOS:000323737200002 |
| Funding Organization | National Natural Science Foundation of China [11272233]; National Key Basic Research and Development Program [2012CB720101]; State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences |
| Classification | 二类 |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://dspace.imech.ac.cn/handle/311007/47458 |
| Collection | 非线性力学国家重点实验室 |
| Corresponding Author | Jiang, N (reprint author), Tianjin Key Lab Modern Engn Mech, Tianjin 300072, Peoples R China. |
| Recommended Citation GB/T 7714 | Guan XL,Yao SY,Jiang N,et al. A study on coherent structures and drag-reduction in the wall turbulence with polymer additives by TRPIV[J]. ACTA MECHANICA SINICA,2013,29,4,:485-493. |
| APA | Guan XL,Yao SY,Jiang N,&Jiang, N .(2013).A study on coherent structures and drag-reduction in the wall turbulence with polymer additives by TRPIV.ACTA MECHANICA SINICA,29(4),485-493. |
| MLA | Guan XL,et al."A study on coherent structures and drag-reduction in the wall turbulence with polymer additives by TRPIV".ACTA MECHANICA SINICA 29.4(2013):485-493. |
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