Modelling the Effect of Tree Foliage on Sprayer Airflow in Orchards

Abstract

The effect of tree foliage on sprayer airflow through pear trees in a fruit orchard was studied and modelled in detail. A new three-dimensional (3-D) computational fluid dynamics model that integrates the 3-D canopy architecture with a local closure model to simulate the effect of the stem and branches and leaves of trees separately on airflow was developed. The model was validated with field observations made in an experimental orchard (pcfruit, Sint-Truiden, Belgium) in spring and summer 2008 and was used to investigate the airflow from three air-assisted orchard sprayers (Condor V, Duoprop and AirJet quatt). Velocity magnitudes were measured before and behind leafless and fully-leafed pear canopies across the row while the operating sprayers are passing along the row, and were compared with the simulations. The simulation results predicted the measured values well with all the local relative errors within 20%. The effect of foliar density on airflow from the three air assisted sprayers was manifested by changing the magnitude and direction of the sprayers' air velocity behind the canopy, especially at the denser regions of the canopy and by changing the pattern of velocity decay horizontally along the jet. The developed methodology will also allow a thorough investigation of atmospheric airflow in canopy structures.

Foliage motion under wind, from leaf flutter to branch buffeting

“…But motion is also a dominant factor in seed or pollen ejection, thereby affecting plant reproduction [12,13]. Motion also affects the duration of water retention on leaves, a key factor in pathogen development, and conversely, the capture of pesticides [14][15][16].…”

“…To summarize, understanding the wind-induced motion of plants is of interest in many fields of plant science, agronomy, biology and engineering. For instance, in biology, it is essential to understand how trees extract energy from their windy environment [9], in agronomy, it is essential to understand how foliage motion may improve the efficiency of pesticide spreading [15] and finally in computer science, it is essential to make realistic outdoor scenes using low computational resources [25].…”

Large-Eddy Simulation of Inhomogeneous Canopy Flows Using High Resolution Terrestrial Laser Scanning Data

“…Notable exceptions are the investigation of isolated trees (Endalew et al 2009(Endalew et al , 2011, fractal plant models (Chester and Meneveau 2007), or arrays of simple, crop-like structures (e.g. Yue et al 2007;Dupont et al 2010).…”

Evaluation of Laser Range-Finder Mapping for Agricultural Spraying Vehicles

“…The tree height and density is later used by a variable-rate spraying controller, resulting in more precise and directed application of the chemicals. Other examples include a review of different tree area estimation methods [14], 3d fluid dynamics modelling for improved spraying [6], and range-based real-time control of the spraying [15].…”