气候变化领域集成服务门户(CCPortal): Symmetric shear banding and swarming vortices in bacterial superfluids

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DOI	10.1073/pnas.1722505115
	Symmetric shear banding and swarming vortices in bacterial superfluids
	Guo S.; Samanta D.; Peng Y.; Xu X.; Cheng X.
发表日期	2018
ISSN	0027-8424
起始页码	7212
结束页码	7217
卷号	115 期号:28
英文摘要	Bacterial suspensions—a premier example of active fluids—show an unusual response to shear stresses. Instead of increasing the viscosity of the suspending fluid, the emergent collective motions of swimming bacteria can turn a suspension into a superfluid with zero apparent viscosity. Although the existence of active superfluids has been demonstrated in bulk rheological measurements, the microscopic origin and dynamics of such an exotic phase have not been experimentally probed. Here, using high-speed confocal rheometry, we study the dynamics of concentrated bacterial suspensions under simple planar shear. We find that bacterial superfluids under shear exhibit unusual symmetric shear bands, defying the conventional wisdom on shear banding of complex fluids, where the formation of steady shear bands necessarily breaks the symmetry of unsheared samples. We propose a simple hydrodynamic model based on the local stress balance and the ergodic sampling of nonequilibrium shear configurations, which quantitatively describes the observed symmetric shear-banding structure. The model also successfully predicts various interesting features of swarming vortices in stationary bacterial suspensions. Our study provides insights into the physical properties of collective swarming in active fluids and illustrates their profound influences on transport processes.
英文关键词	Active fluids; Bacterial suspensions; Shear banding
语种	英语
scopus关键词	Article; bacterial phenomena and functions; bacterial superfluid; bacterial suspension; controlled study; flow measurement; hydrodynamics; mathematical model; prediction; priority journal; quantitative analysis; shear flow; biological model; cytology; Escherichia coli K 12; physiology; shear strength; Escherichia coli K12; Models, Biological; Shear Strength
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160496
作者单位	Guo, S., Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, United States, Complex Systems Division, Beijing Computational Science Research Center, Beijing, 100193, China; Samanta, D., Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, United States, Department of Mechanical Engineering, Indian Institute of Technology, Ropar, Rupnagar, Punjab 140001, India; Peng, Y., Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, United States; Xu, X., Complex Systems Division, Beijing Computational Science Research Center, Beijing, 100193, China; Cheng, X., Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, United States
推荐引用方式 GB/T 7714	Guo S.,Samanta D.,Peng Y.,et al. Symmetric shear banding and swarming vortices in bacterial superfluids[J],2018,115(28).
APA	Guo S.,Samanta D.,Peng Y.,Xu X.,&Cheng X..(2018).Symmetric shear banding and swarming vortices in bacterial superfluids.Proceedings of the National Academy of Sciences of the United States of America,115(28).
MLA	Guo S.,et al."Symmetric shear banding and swarming vortices in bacterial superfluids".Proceedings of the National Academy of Sciences of the United States of America 115.28(2018).