A study on coherent structures and drag-reduction in the wall turbulence with polymer additives by TRPIV

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	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)
刊名	ACTA MECHANICA SINICA
	2013-08
通讯作者邮箱	nanj@tju.edu.cn
卷号	29 期号:4 页码:485-493
关键词	Time-resolved particle image velocimetry Wall-bounded turbulence Coherent structures Polymer additives Drag reduction
ISSN号	0567-7718
通讯作者	Jiang, N (reprint author), Tianjin Key Lab Modern Engn Mech, Tianjin 300072, Peoples R China.
产权排序	[Guan, Xin-Lei; Yao, Shi-Yong; Jiang, Nan] Tianjin Univ, Dept Mech, Tianjin 300072, Peoples R China; [Jiang, Nan] Tianjin Key Lab Modern Engn Mech, Tianjin 300072, Peoples R China; [Jiang, Nan] Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China; [Jiang, Nan] Nankai Univ Tianjin Univ Ctr Liu Hui Appl Math, Tianjin 300072, Peoples R China
合作状况	国内
中文摘要	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.
学科主题	湍流
分类号	二类
收录类别	SCI ; EI ; CSCD
资助信息	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
原文出处	http://dx.doi.org/10.1007/s10409-013-0035-0
语种	英语
WOS记录号	WOS:000323737200002
公开日期	2013-09-27
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/47458]
专题	力学研究所_非线性力学国家重点实验室
推荐引用方式 GB/T 7714	Guan XL,Yao SY,Jiang N. 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.(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.