A computational and wind tunnel study of particle dry deposition in complex topography

An understanding of the likely pattern of dry deposition of small particles over a landscape is a key prerequisite to designing strategies for sampling ground contamination following routine or accidental releases to atmosphere. Wind tunnel and computational fluid dynamics studies of flow and particle deposition over landscape features have been carried out. The presence of elevated landscape features showed a strong effect on the pattern of deposition relative to a flat landscape case. A relatively small area of increased deposition occurred on the upwind face, with a larger area of decreased deposition in the wake. The slope of the landscapes affected the magnitude of the effect and the size of the affected region in the wake. The pattern of deposition for a three-dimensional landscape was complex. Good quantitative agreement was seen between the CFD predicted deposition and the wind tunnel results for the two-dimensional cases and reasonable qualitative agreement for the three-dimensional case, suggesting that CFD studies might be an appropriate tool to systematically explore the influence of complex topography on particle deposition.