A Turbulence-Based Bed-Load Transport Model for Bare and Vegetated Channels
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Yang_Nepf_GRL2018.pdf
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Manuscript
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377.67 KB
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99972aede336bdf170121ef2f01d9ded
Author(s)
Nepf, Heidi
Yang, Qingjun
Date Issued
September 2018
Journal
Geophysical Research Letters
Publisher
American Geophysical Union (AGU)
Citation
Yang, J. Q., and H. M. Nepf. “A Turbulence-Based Bed-Load Transport Model for Bare and Vegetated Channels.” Geophysical Research Letters, Oct. 2018.
Version
Author's final manuscript
Abstract
Previous studies have shown that sediment transport models based on bed shear stress (τ) are not accurate for regions with vegetation. The present study demonstrated that the inaccuracy arises from the influence of vegetation‐generated turbulence. Bed‐load transport rate, Q[subscript s], and near‐bed velocity were measured in a sediment‐recirculating flume with model vegetation of different vegetation volume fractions (ϕ) and with bare sand beds. At the same τ, the measured Q[subscript s] increased with increasing ϕ, suggesting that vegetation‐generated turbulence, which also increased with increasing ϕ, was augmenting the bed‐load transport. At the same near‐bed turbulent kinetic energy, k[subscript t], the Q[subscript s] measured in both bare and vegetated channels agreed within uncertainty, suggesting that k[subscript t] may be a more universal predictor of bed‐load transport than bed shear stress. A τ‐based bed‐load transport model was reinterpreted as a k[subscript t]‐based model. The new k[subscript t]‐based model predicted the Q[subscript s] measurements for both bare and vegetated channels.
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/10.1029/2018GL079319
