Influence of shear stress fluctuation on bed particle mobility.

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Influence of shear stress fluctuation on bed particle mobility.

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dc.contributor.author Cheng, Nian-Sheng
dc.date.accessioned 2012-03-22T07:26:16Z
dc.date.available 2012-03-22T07:26:16Z
dc.date.copyright 2006
dc.date.issued 2012-03-22
dc.identifier.citation Cheng, N. S. (2006). Influence of shear stress fluctuation on bed particle mobility. Physics of Fluids, 18 (9).
dc.identifier.uri http://hdl.handle.net/10220/7661
dc.description.abstract Whether or not a sediment particle is entrained from a channel bed is associated with both average bed shear stress and shear stress fluctuation, the latter being flow-dependent and also related to bed irregularities. In the first part of this study, a preliminary analysis of possible fluctuations induced by bed roughness is presented for the case of an immobile plane bed comprised of unisized sediments. The result shows that the roughness-induced variation is generally comparable to that associated with near-bed turbulence, and both variations can be approximated as log-normal in terms of probability density distribution. The bed particle mobility is then analyzed by considering the effects of shear stress fluctuations. The relevant computations demonstrate that with increasing shear stress fluctuations, the probability of the mobility of a bed particle may be enhanced or weakened. For the case of low sediment entrainment, the probability is increased by turbulence. However, the probability may be reduced by the shear stress fluctuation if the average bed shear stress becomes relatively higher. This study shows that the critical condition for initial sediment motion could be overestimated if the Shields diagram is applied for the condition of flows with high turbulence intensities.
dc.format.extent 7 p.
dc.language.iso en
dc.relation.ispartofseries Physics of fluids
dc.rights © 2006 American Institute of Physics. This paper was published in Physics of Fluids and is made available as an electronic reprint (preprint) with permission of American Institute of Physics. The paper can be found at the following DOI: [http://dx.doi.org/10.1063/1.2354434]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.
dc.subject DRNTU::Engineering::Civil engineering::Water resources
dc.title Influence of shear stress fluctuation on bed particle mobility.
dc.type Journal Article
dc.contributor.school School of Civil and Environmental Engineering
dc.identifier.doi http://dx.doi.org/10.1063/1.2354434
dc.description.version Published version

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