In the first paper, the mechanisms of particle capture and coalescence of aerosols by a moving water drop in the atmosphere are studied using the boundary-layer flow approximation. The particle trajectory is computed by solving the equations of motion of the particle both outside and inside the boundary layer using the Adams-Moulton method. The grazing trajectory is found by a trial-and-error technique. The collision and collection efficiencies of scavenging due to particle inertia and to the velocity gradient of the flow field are then computed for water drops ranging from 0.1 to 1.0 mm in radius and for particle of 1 - 10 µ in radius. The results obtained in this work are in good agreement with experimental data given by Walton and Woolcock.
In the second paper, the effects of intermolecular forces on the collection efficiency of submicron aerosol particles are studied. It is assumed that the intermolecular forces provide a certain region as an absorbent surface in the vicinity of the drop. Numerical results have been obtained for the cases of a water drop collecting AgCl aerosols and a water drop collecting submicron cloud droplets. It is found that the collection efficiency depends mainly on the diffusion process. Our calculations agree reasonably well with recent experimental results of Kerker for AgCl aerosols for the case of small drop --Abstract, page iii
