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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

The formation and migration of sand ripples in closed conduits: Experiments with turbulent water flows

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Author(s):
Cardona Florez, Jorge Eduar [1] ; Franklin, Erick de Moraes [1]
Total Authors: 2
Affiliation:
[1] UNICAMP Univ Campinas, Fac Mech Engn, BR-13083860 Campinas, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: EXPERIMENTAL THERMAL AND FLUID SCIENCE; v. 71, p. 95-102, FEB 2016.
Web of Science Citations: 4
Abstract

The transport of solid particles by a fluid flow is frequently found in nature and industry. Some examples are the transport of sand in rivers and hydrocarbon pipelines. When the shear stresses exerted by a fluid flow on a granular bed remain moderate, some grains are set in motion without fluidizing the bed; the moving grains form a layer, known as bed load, that moves while maintaining contact with the fixed part of the bed. Under bed load conditions, the granular bed may become unstable, generating ripples and dunes. Sand ripples are commonly observed in closed conduits and pipes such as in petroleum pipelines, sewer systems, and dredging lines. Although of importance for many scientific domains and industrial applications, the formation of ripples in closed conduits is not well understood, and the problem is still open. This paper presents an experimental study on the formation and migration of sand ripples under a turbulent closed-conduit flow and bed-load conditions. In our experiments, fully-developed turbulent water flows were imposed over a granular bed of known granulometry in a transparent channel, and bed load took place. For different water flow rates and grain diameters, the growth and migration of bedforms were filmed by a high-definition camera, and a numerical code was developed to determine the wavelength and celerity of the bedforms from the acquired images. The obtained results are compared with published stability analyses. (C) 2015 Elsevier Inc. All rights reserved. (AU)

FAPESP's process: 12/19562-6 - The transport of grains as bed-load and the instabilities of a granular bed
Grantee:Erick de Moraes Franklin
Support Opportunities: Research Grants - Young Investigators Grants