Modelling of the resuspension of particle clusters from multilayer aerosol deposits with variable porosity

A model for the resuspension of multilayer aerosol deposits has been developed taking into account the dependence of resuspension rates on the deposit structure, as well as the fact that particles are typically resuspended in clusters. The model is based on three main concepts: Constructing artificial, irregular particle deposits with variable bed porosity; identifying resuspendable clusters on the surface of these deposits by means of a sufficiently simple topological criterion; and assigning resuspension probabilites per unit time to resuspendable clusters based on a balance between forces of adhesion and turbulent bursts. The model accounts at least qualitatively for several experimental observations not predicted so far by any previous resuspension model. A similarity analysis of the model leads to the identification of non-dimensional groups that could possibly be used in empirical correlations.