The incipient motion of sediment in a channel with model emergent vegetation
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Yang.River_flow_2016.pdf
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4.11 MB
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f1aa2a375c1ae80ce0af2210bafa35df
Author(s)
Chung, Hayoon
Nepf, Heidi
Yang, Qingjun
Date Issued
September 2016
Journal
River flow 2016: Proceedings of the International Conference on Fluvial Hydraulics
Citation
Yang, Judy, Hayoon Chung, and Heidi Nepf. “The Incipient Motion of Sediment in a Channel with Model Emergent Vegetation.” River Flow 2016: Proceedings of the International Conference on Fluvial Hydraulics, 11-24 July, 2016, St. Louis, Missouri, CRC Press, 2016.
Version
Author's final manuscript
Abstract
In a bare channel (without vegetation), the incipient velocity for sediment motion, U[subscript crit], has historically been related to the mean bed shear stress ([bar over τ]) o or friction velocity (U[subscript ∗] = √[bar over τ]/ρ). More recent studies, however, suggest turbulence also plays a role. This paper examines whether the onset of sediment motion in a vegetated channel is correlated with U[subscript ∗], or turbulence (k[subscript τ). Images collected with a digital camera were interrogated with a particle-tracking code to measure sediment transport for different vegetation density and channel velocity. The trend in sediment transport with channel velocity was used to identify U[subscript crit] for each stem density. The values of k[subscript τ and U[subscript ∗] were estimated at Ucrit. However, none of these parameters produced a constant threshold across all stem density and bare bed. We construct a new metric representing the peak turbulent velocities impinging on the bed that produces a constant threshold value for all cases.
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1201/9781315644479-148
