Europhys. Lett.
Volume 71, Number 2, July 2005
Page(s) 186 - 192
Section General
Published online 10 June 2005
Europhys. Lett., 71 (2), pp. 186-192 (2005)
DOI: 10.1209/epl/i2004-10532-7

Caustics in turbulent aerosols

M. Wilkinson1 and B. Mehlig2

1  Faculty of Mathematics and Computing, The Open University Walton Hall, Milton Keynes, MK7 6AA, UK
2  Department of Physics, Göteborg University - 41296 Gothenburg, Sweden

received 29 October 2004; accepted in final form 12 May 2005
published online 10 June 2005

Networks of caustics can occur in the distribution of particles suspended in a randomly moving gas. These can facilitate coagulation of particles by bringing them into close proximity, even in cases where the trajectories do not coalesce. The evolution of these caustic patterns depends upon the Lyapunov exponents $\lambda_1$, $\lambda_2$ of the suspended particles, as well as the rate J at which particles encounter caustics. We develop a theory determining the quantities J, $\lambda_1$, $\lambda_2$ from the statistical properties of the gas flow, in the limit of short correlation times.

05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.
47.27.Qb - Turbulent diffusion.
47.54.+r - Fluid dynamics: Pattern selection; pattern formation.

© EDP Sciences 2005