Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: Exotic and Emerging Plant Diseases of Horticultural Crops

Location: Horticultural Crops Research

Title: Mean and turbulent flow statistics in a trellised agricultural canopy

Author
item Miller, Nate
item Stoll, Rob
item Mahaffee, Walter - Walt
item Pardyjak, Eric

Submitted to: Boundary Layer Meteorology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/18/2017
Publication Date: 6/15/2017
Citation: Miller, N., Stoll, R., Mahaffee, W.F., Pardyjak, E. 2017. Mean and turbulent flow statistics in a trellised agricultural canopy. Boundary Layer Meteorology. doi: 10.1007/s10546-017-0265-y.

Interpretive Summary: The air turbulence associated with trellised agricultural canopies (grapes) was investigated in order to better understand how to predict pathogens and pest spread. The canopy was observed to cause wind channeling along rows regardless of wind direction. The channeling would explain numerous of observation of pest and pathogen spread along rows.

Technical Abstract: The architecture of a trellised agricultural canopy presents many similarities to homogeneous plant canopies, windbreaks, and urban canopies including street canyons. Compared to these other canopies, trellised canopies (e.g. vineyard) present an interesting, complex, two-dimensional environment that is not likely described by models developed from homogeneous canopies. To study the flow field within this environment, data from meteorological towers deployed in a vineyard in Oregon was investigated. The data demonstrated that the canopy strongly influenced the flow including channeling the mean wind into the vine row direction regardless of the above-canopy wind direction. This channeling led to measurable turning of the mean velocity profile between the middle of the canopy and the top of the meteorological towers. Additionally, many other flow statistics in the canopy-sub layer where impacted by the canopy architecture and showed dependence based on the difference between the above-canopy wind direction and the vine row direction. This included variations in the displacement height, the turbulent kinetic energy budget, the behavior of the vertical fluxes of momentum and heat, and the scales of importance in the energy spectra. These result indicate that particle flux in trellised canopy will not be predicted by models derived from homogeneous canopies.

Last Modified: 08/23/2017
Footer Content Back to Top of Page