Abstract
We show quantitatively how the collision rate of droplets of visible moisture in turbulent air increases very abruptly as the intensity of the turbulence passes a threshold, due to the formation of fold caustics in their velocity field. The formation of caustics is an activated process, in which a measure of the intensity of the turbulence, termed the Stokes number St, is analogous to temperature in a chemical reaction: the rate of collision contains a factor
DOI: http://dx.doi.org/10.1103/PhysRevLett.97.048501
- Received 7 April 2006
- Published 28 July 2006
© 2006 The American Physical Society