A vortex-based model of velocity and shear stress in a partially vegetated shallow channel
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Nepf-2008-A vortex-based model.pdf
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Author(s)
White, Brian L.
Nepf, Heidi
Date Issued
January 2008
Journal
Water Resources Research
Publisher
American Geophysical Union
Citation
White, Brian L., and Heidi M. Nepf. “A vortex-based model of velocity and shear stress in a partially vegetated shallow channel.” Water Resources Research 44.1 (2008) ©2008 American Geophysical Union
Version
Final published version
Abstract
This paper presents a method for predicting the distributions of velocity and shear stress in shallow channels with a boundary of emergent vegetation. Experiments in a laboratory channel with model vegetation show that the velocity profile exhibits a distinct two-layer structure, consisting of a rapidly varying shear layer across the vegetation interface and a more gradual boundary layer in the main channel. In addition, coherent vortices are observed which span both layers, and are the dominant contributors to lateral momentum fluxes. From these observations, we propose a model for the vortex-induced exchange and find expressions for the width of momentum penetration into the vegetation, the velocity and shear stress at the vegetation edge, and the width of the boundary layer in the main channel. These variables, along with a momentum balance in the main channel, comprise a modeling framework which accurately reproduces the observed velocity and shear stress distributions. The predictions for the velocity and shear stress can provide a basis for modeling flood conveyance, overbank sediment transport, and scalar residence time in the vegetated layer.
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1029/2006WR005651
