Brownian diffusion of submicrometer particles in the viscous sublayer

Diffusion of Brownian submicrometer particles from a point source in the vicous sublayer of a turbulent shear flow near a solid smooth wall is considered in this paper. The equation of motion of particles including the Brownian effect is considered. Ensembles of 500 particle trajectories are evaluated, compiled, and statistically analyzed. Effects of particle size, density ratio, and source distance from the wall on particle concentration profile and wall deposition rate are studied. The results are compared with those obtained from the exact solution to the corresponding convective diffusion equation in the absence of turbulent fluctuations. The effect of turbulence near a wall is also considered. The results show that the Brownian effects play a significant role in the diffusion of submicrometer particles at distances less than 2 wall units from the solid surface. The effect of turbulence, however, could become significant during the ejection/inrush process.