B. Andersson et al 2007 EPL 80 69001 doi:10.1209/0295-5075/80/69001
B. Andersson1, K. Gustavsson1, B. Mehlig1 and M. Wilkinson2
Show affiliationsSmall particles advected in a fluid can collide (and therefore aggregate) due to the stretching or shearing of fluid elements. This effect is usually discussed in terms of a theory due to Saffman and Turner (J. Fluid Mech., 1 (1956) 16). We show that in complex or random flows the Saffman-Turner theory for the collision rate describes only an initial transient (which we evaluate exactly). We obtain precise expressions for the steady-state collision rate for flows with small Kubo number, including the influence of fractal clustering on the collision rate for compressible flows. For incompressible turbulent flows, where the Kubo number is of order unity, the Saffman-Turner theory is an upper bound.
05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion
Issue 6 (December 2007)
Received 8 October 2007, accepted for publication 23 October 2007
Published 20 November 2007
Total article downloads: 140
B. Andersson et al 2007 EPL 80 69001
K. Gustavsson and B. Mehlig 2011 EPL 96 60012