Prediction of particle deposition on to rough surfaces

Lagrangian stochastic models applicable to the prediction of particle deposition onto hydraulically smooth surfaces are extended to account for the effects of surface roughness. Within the modelling approach, roughness elements are treated as mass 'sinks' volumetrically distributed within the flows. The extreme sensitivity of the deposition of micron and sub-micron sized particles to the micro-roughness of hydraulically smooth surfaces is shown to be very well predicted. This suggests that the models can be used to predict the deposition of particles onto leaves and other natural surfaces with micro-roughness elements correctly. Model predictions for the deposition velocities of spores and pollens onto completely rough sticky surfaces are shown to be in very close agreement with the experiment. (C) 2000 Elsevier Science B.V. All rights reserved.