A new theory of aerosol deposition from turbulent fluids

The author's previously published theory[2] of mass (or heat) transfer to very rough surfaces predicts a power dependence on Sc of ?$\text{1}\text{2}$ (compared with ?$\text{2}\text{3}$ for smooth surfaces). This expected change of $\text{1}\text{6}$ in the power has previously proved difficult to test precisely, but it is shown here that available data on the deposition of small aerosol particles (Sc ～ 10⁶) confirm that the deposition is indeed 10 times faster on very rough surfaces.For larger aerosol particles, however, deposition rates depend strongly on roughness characteristics, as expected from the author's interception and impaction theory[13]. This assumes an x-directional deposition on to the roughness elements, the latter being very important to the process. Comparison of published data with the new theory, and with typical surface roughnesses, supports the proposed theory (eqn 4).