How Different Cross-Sectional Shapes Influence the Separation Zone of an Open-Channel Confluence
Publication: Journal of Hydraulic Engineering
Volume 143, Issue 9
Abstract
A key feature of a schematized open-channel confluence is the separation zone that is present when the tributary flow detaches from the downstream corner of the confluence. This zone of recirculating fluid influences head losses, as well as sediment and solute balances. Most laboratory studies on the separation zone were, however, made in flumes having a rectangular cross-sectional shape. The objective of this research is therefore to elaborate on the influence of the cross-sectional shape on the flow patterns in a 90° confluence. A validated large-eddy simulation (LES) model is used to study the flow in confluences with four different cross-sectional shapes. The results indicate that the dimensions of the separation zone are significantly different for nonrectangular shapes due to lateral currents that might reduce the local momentum deficit. This study contributes to finding the optimal shape of artificial confluences with respect to head losses, as well as to understanding the flow processes that are present in a confluence.
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Acknowledgments
The anonymous reviewers and associate editor are gratefully acknowledged for their thorough revision. The first author is a Ph.D. fellow of the Research Foundation—Flanders. The second author is a Ph.D. fellow of the Special Research Fund (BOF) of Ghent University. The computational resources (Stevin Supercomputer Infrastructure) and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by Ghent University, the Hercules Foundation, and the Flemish Government Department of Economy, Science and Innovation (Department EWI).
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Published In
Journal of Hydraulic Engineering
Volume 143 • Issue 9 • September 2017
Copyright
©2017 American Society of Civil Engineers.
History
Received: Jul 6, 2016
Accepted: Feb 28, 2017
Published online: Jun 26, 2017
Published in print: Sep 1, 2017
Discussion open until: Nov 26, 2017
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