STOCHASTIC MODELING OF TURBULENT SPRAY DISPERSION IN THE NEAR-FIELD OF ORCHARD SPRAYERS

A Lagrangian approach is adopted to study the turbulent dispersion of spray droplets in the near-field of air-assisted orchard sprayers. In order to compute the mean and turbulent properties of the air flow gen erated by the moving sprayer, the generalised mass and momentum conser vation equations, coupled with a k-epsilon turbulence model, are solve d numerically using finite volume methodology. These equations utilise a spatial-averaged porous medium model to take into account the effec t of interactions between the air flow and crop. Airborne spray flux d istributions have been calculated from ensemble-averaged particle traj ectories predicted by two random-walk models (i.e. with and without te mporal correlation). The results show that both stochastic models give reasonable agreement with measured drift profiles. (C) 1998 Elsevier Science Ltd. All rights reserved.