Predicting Equilibrium Scour-Hole Geometry near Angled Stream Deflectors Using a Three-Dimensional Numerical Flow Model
Publication: Journal of Hydraulic Engineering
Volume 133, Issue 8
Abstract
Stream rehabilitation projects often involve the installation of instream structures such as flow deflectors. The objective of this study is to use the output of a three-dimensional numerically simulated flow field over a flat, predeformation bed to predict the planform extent of the equilibrium scour hole near stream deflectors of varying angles. It is shown that the upstream extent of the simulated flow separation zone determines the upstream limit of scour, whereas the lateral scour extent at the nose of the deflector is determined by the width of the separation zone. Further, scour depths are greatest in regions where strong downwelling (negative vertical velocity) exists, and the position of the local minimum dynamic pressure point in the simulated flow field defines the downstream limit of scouring. The results have implications for future design of habitat improvement structures where different angles and lengths of structures could potentially be tested prior to their implementation to determine the resultant scour geometry.
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Acknowledgments
This research was funded by an NSERC Grant (Biron) and scholarship (Haltigin). Thanks to the technicians in the Hydraulics Laboratory at McGill University, John Bartczak and Damon Kiperchuk. Also thanks to Stuart Lane and Richard Hardy for fruitful discussion on three-dimensional flow modeling. This note has benefited greatly from the constructive suggestions of two anonymous reviewers.
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Published In
Journal of Hydraulic Engineering
Volume 133 • Issue 8 • August 2007
Pages: 983 - 988
Copyright
© 2007 ASCE.
History
Received: Aug 16, 2005
Accepted: Jan 4, 2007
Published online: Aug 1, 2007
Published in print: Aug 2007
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