Critical Flow Velocity for Incipient Sediment Motion in Open Channel Flow with Rigid Emergent Vegetation
Publication: Journal of Engineering Mechanics
Volume 146, Issue 11
Abstract
In vegetated open channel flow, sediment transport is affected by both boundary shear and vegetation-induced turbulence. This study presents a theoretical derivation of the critical flow condition for incipient sediment motion, which is evaluated in the reach scale in the presence of emergent vegetation simulated with cylindrical rods. To take into account the combined effects of both mean flow and turbulence on sediment motion, a spatiotemporal average is applied to the force balance equation. The analysis shows that the critical condition can be formulated in terms of the dependence of the densimetric Froude number on the vegetation concentration for the condition of hydrodynamically rough turbulent flows. The derived theoretical formula is consistent with laboratory measurements reported in previous studies.
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Data Availability Statement
Some or all data, models, or code generated or used during the study are available from the corresponding author by request, including experimental data used in Figs. 3 and 4.
Acknowledgments
The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 51979242).
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Published In
Journal of Engineering Mechanics
Volume 146 • Issue 11 • November 2020
Copyright
© 2020 American Society of Civil Engineers.
History
Received: Jan 7, 2020
Accepted: Jun 8, 2020
Published online: Aug 21, 2020
Published in print: Nov 1, 2020
Discussion open until: Jan 21, 2021
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