Exchange flow between open water and floating vegetation
Name
Nepf-Exchange Flow.pdf
Size
4.62 MB
Format
Adobe PDF
Checksum (MD5)
5bcfbbacb8b3bdf629f7eeef4344692b
Author(s)
Zhang, Xueyan
Nepf, Heidi
Date Issued
June 2011
Journal
Environmental Fluid Mechanics
Publisher
Springer Science + Business Media
Citation
Zhang, Xueyan, and Heidi M. Nepf. “Exchange flow between open water and floating vegetation.” Environmental Fluid Mechanics 11.5 (2011): 531-546.
Version
Author's final manuscript
Abstract
This study describes the exchange flow between a region with open water and a region with a partial-depth porous obstruction, which represents the thermally-driven exchange that occurs between open water and floating vegetation. The partial-depth porous obstruction represents the root layer, which does not penetrate to the bed. Initially, a vertical wall separates the two regions, with fluid of higher density in the obstructed region and fluid of lower density in the open region. This density difference represents the influence of differential solar heating due to shading by the vegetation. For a range of root density and root depths, the velocity distribution is measured in the lab using PIV. When the vertical wall is removed, the less dense water flows into the obstructed region at the surface. This surface flow bifurcates into two layers, one flowing directly through the root layer and one flowing beneath the root layer. A flow directed out of the vegetated region occurs at the bed. A model is developed that predicts the flow rates within each layer based on energy considerations. The experiments and model together suggest that at time- and length-scales relevant to the field, the flow structure for any root layer porosity approaches that of a fully blocked layer, for which the exchange flow occurs only beneath the root layer.
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike 3.0
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1007/s10652-011-9213-4
