Caustics in turbulent aerosols

Abstract

Networks of caustics can occur in the distribution of particles suspended in\na randomly moving gas. These can facilitate coagulation of particles by\nbringing them into close proximity, even in cases where the trajectories do not\ncoalesce. We show that the long-time morphology of these caustic patterns is\ndetermined by the Lyapunov exponents lambda_1, lambda_2 of the suspended\nparticles, as well as the rate J at which particles encounter caustics. We\ndevelop a theory determining the quantities J, lambda_1, lambda_2 from the\nstatistical properties of the gas flow, in the limit of short correlation\ntimes.\n