Simulation of particle deposition beneath Faraday waves in thin liquid films

Simulations are presented of particle deposition beneath shallow, standing capillary waves. The standing waves occur on the surface of a thin liquid film. The film is sufficiently thin such that the wave motion affects the trajectories of the settling particles. The simulations reveal that particles of all size tend to accumulate at specific nodal regions beneath the waves, and that there is an optimal particle diameter for which this accumulation is maximized. The diameter at which this maximal accumulation occurs is a function of the wave field, the fluid thickness, the particle density, and the fluid properties. The accumulation is quantified by the standard deviation of the final location of the settling particles and plots are presented of this standard deviation as a function of particle diameter. Previous experimental work has shown that this method can be implemented by generating standing Faraday waves on the surface of thin films of a liquid/particulate mixture. The present work shows how these films can be tailored via the particle diameter, liquid thickness, and wavelength. Some aspects relevant to the practical implementation of the method are also discussed. (C) 2005 American Institute of Physics.