Evaluation of a random displacement model for predicting particle escape from canopies using a simple eddy diffusivity model
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Follett.Etal.Submitted.pdf
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2.91 MB
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0e33f3bc9a61e2471095fe6cb722c781
Author(s)
Chamecki, Marcelo
Nepf, Heidi
Follett, Elizabeth M
Date Issued
August 2016
Journal
Agricultural and Forest Meteorology
Publisher
Elsevier
Citation
Follett, Elizabeth et al. “Evaluation of a Random Displacement Model for Predicting Particle Escape from Canopies Using a Simple Eddy Diffusivity Model.” Agricultural and Forest Meteorology 224 (August 2016): 40–48 © 2016 Elsevier B.V.
Version
Author's final manuscript
Abstract
There is a need for more practical tools for estimating spore escape from crop canopies, which is essential in forecasting the propagation of disease to other fields. In this paper, we evaluated whether a random displacement model (RDM) parameterized with an eddy diffusivity could be used to predict spore escape probability. The proposed RDM does not require detailed turbulence measurements for parameterization. Instead, it constructs profiles of velocity and eddy diffusivity from a simple set of parameters [canopy height, canopy density, vegetation length scale, and wind speed]. The RDM was validated using field measurements of spore concentration. On average, the model predictions matched the field measurements within 28% inside the canopy and 42% above it, comparable to LES results over the same canopy. Once validated, the RDM was used to explore particle escape across a range of canopy densities and particle settling velocities, in order to inform estimates of particle escape from crops of varying maturity or area density. Escape fraction as calculated by the RDM increased as canopy density decreased, as the ratio of particle settling velocity to turbulent shear velocity ratio decreased, and as the source height within the canopy increased. Keywords:
Particle transport; Escape of particles from canopy; Eddy diffusivity; Random displacement model; Maize
MIT Department
Massachusetts Institute of Technology. Department of Civil and Environmental Engineering
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/j.agrformet.2016.04.004
