Flow and Transport in Regions with Aquatic Vegetation
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Nepf pre-press with Figures.pdf
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11.66 MB
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Adobe PDF
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Author(s)
Nepf, Heidi
Date Issued
January 2012
Journal
Annual Review of Fluid Mechanics
Publisher
Annual Reviews
Citation
Nepf, Heidi M. Flow and Transport in Regions with Aquatic Vegetation. Annual Review of Fluid Mechanics 44, no. 1 (January 21, 2012): 123-142.
Version
Author's final manuscript
Abstract
This review describes mean and turbulent flow and mass transport in the presence of aquatic vegetation. Within emergent canopies, the turbulent length scales are set by the stem diameter and spacing, and the mean flow is determined by the distribution of the canopy frontal area. Near sparse submerged canopies, the bed roughness and near-bed turbulence are enhanced, but the velocity profile remains logarithmic. For dense submerged canopies, the drag discontinuity at the top of the canopy generates a shear layer, which contains canopy-scale vortices that control the exchange of mass and momentum between the canopy and the overflow. The canopy-scale vortices penetrate a finite distance into the canopy, δe, set by the canopy drag. This length scale segregates the canopy into two regions: The upper canopy experiences energetic turbulent transport, controlled by canopy-scale vortices, whereas the lower canopy experiences diminished transport, associated with the smaller stem-scale turbulence. The canopy-scale vortices induce a waving motion in flexible blades, called a monami.
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
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Creative Commons Attribution-Noncommercial-Share Alike 3.0
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DOI of Published Version
https://doi.org/10.1146/annurev-fluid-120710-101048