Dry deposition model for a microscale aerosol dispersion solver based on the moment method

A dry deposition model suitable for use in the microscale solver based on the moment method has been developed. Contributions from five main processes driving the deposition - Brownian diffusion, interception, impaction, turbulent impaction, and sedimentation - are included in the model. The deposition model was employed in the moment method solver implemented in the OpenFOAM framework. Applicability of the developed expression and the moment method solver was tested on two example problems of particle dispersion in the presence of a vegetation on small scales: a flow through a tree patch in 2D and a flow through a hedgerow in 3D. Comparison with the sectional method showed that the moment method using the developed deposition model is able to reproduce the shape of the particle size distribution well. The relative difference in terms of the volume concentration was below 3% in both tested cases, and decreased away from the vegetation. When tested on the 3D test case, the moment method achieved approximately fivefold acceleration compared to the sectional method using 51 bins.