Closed-Conduit Bed-Form Initiation and Development

Nonintrusive measurement of closed-conduit erodible-bed development was undertaken for 12 experiments of ranges of flow strengths and sediment (solids) sizes. Analogous to open-channel flows, wavelets on the sediment bed of a closed-conduit are instigated by discontinuities in the bed, with wavelet...

Full description

Saved in:
Bibliographic Details
Published in:Journal of hydraulic engineering (New York, N.Y.) N.Y.), 2003-12, Vol.129 (12), p.956-965
Main Authors: Coleman, Stephen E, Fedele, Juan J, Garc, Marcelo H
Format: Article
Language:English
Subjects:
Applied sciences
Bed load movement
Bed ripples
Bed roughness
Buildings. Public works
Computational fluid dynamics
Conduits
Dunes
Exact sciences and technology
Friction factor
Hydraulic constructions
Piping
Sediments
Sewer systems
Solids flow
Stormwater
TECHNICAL PAPERS
Water supply. Pipings. Water treatment
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Nonintrusive measurement of closed-conduit erodible-bed development was undertaken for 12 experiments of ranges of flow strengths and sediment (solids) sizes. Analogous to open-channel flows, wavelets on the sediment bed of a closed-conduit are instigated by discontinuities in the bed, with wavelet lengths for laminar and turbulent open-channel and closed-conduit flows given by λ=175d0.75, where and sediment size d are in millimeters. For closed-conduit flows, ripples, and dunes grow from these wavelets (at rates increasing with increasing flow strength, and utilizing the mechanisms of bed-form coalescence and throughpassing) to limiting lengths, heights, steepnesses, and bed friction factors that are approximately maintained or possibly decrease thereafter. Limitation of free-surface deformation results in increased rates of bed-wave development for closed-conduit flows in comparison to open-channel flows. Measured results indicate that equilibrium closed-conduit ripple and dune magnitudes can be predicted using relations derived for equivalent open-channel flows. The present findings are of particular relevance for understanding and modeling engineering activities ranging from dredging to transport of solids in stormwater and sewer systems, bed-form transport of solids in closed conduits influencing (potentially markedly) conduit conveyance, rate of solids transport, and system head losses for such flows.
ISSN:0733-9429
1943-7900
DOI:10.1061/(ASCE)0733-9429(2003)129:12(956)