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); Jiang, N (reprint author), Tianjin Key Lab Modern Engn Mech, Tianjin 300072, Peoples R China.
发表期刊	ACTA MECHANICA SINICA
	2013-08
卷号	29 期号:4 页码:485-493
ISSN	0567-7718
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.
关键词	Time-resolved Particle Image Velocimetry Wall-bounded Turbulence Coherent Structures Polymer Additives Drag Reduction
学科领域	湍流
URL	查看原文
收录类别	SCI ; EI ; CSCD
语种	英语
WOS记录号	WOS:000323737200002
项目资助者	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
论文分区	二类
引用统计	被引频次：11[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/47458
专题	非线性力学国家重点实验室
通讯作者	Jiang, N (reprint author), Tianjin Key Lab Modern Engn Mech, Tianjin 300072, Peoples R China.
推荐引用方式 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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