Similitude of Large-Scale Turbulence in Experiments on Local Scour at Cylinders
Publication: Journal of Hydraulic Engineering
Volume 132, Issue 1
Abstract
The writers’ experiments on local scour at vertical cylinders placed in a sand bed show that similitude of large-scale turbulence is an important consideration influencing equilibrium depth of local scour. For the range of cylinder diameters used in their experiments, the writers identify a direct trend between equilibrium scour depth (normalized with cylinder diameter) and the intensity and frequency of large-scale turbulence shed from each cylinder; values of normalized scour depth increased when cylinder diameter decreased. The writers offer a scour-depth adjustment factor to account for this trend, which essentially is a scale effect incurred with experiments involving three independent length scales: cylinder diameter, bed-particle diameter, and flow depth. The consequent similitude consideration, or scale effect, has general significance for laboratory studies of local scour associated with hydraulic structures in sediment beds.
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Acknowledgments
The writers appreciatively acknowledge the comments provided by reviewers of this paper. The study described herein is part of Project No. 24-20 (Prediction of Abutment Scour) conducted for the U.S. National Cooperative Highway Program.
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Information
Published In
Journal of Hydraulic Engineering
Volume 132 • Issue 1 • January 2006
Pages: 33 - 40
Copyright
© 2005 ASCE.
History
Received: Sep 9, 2004
Accepted: Feb 3, 2005
Published online: Jan 1, 2006
Published in print: Jan 2006
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