https://doi.org/10.1007/s100510170115
Two-particle dispersion in model two-dimensional velocity fields
Theoretische Polymerphysik,
Universität Freiburg, Hermann-Herder-Str. 3,
79104 Freiburg, Germany
Corresponding author: a igor@tpoly.physik.uni-freiburg.de
Received:
13
March
2001
Published online: 15 August 2001
We consider two-particle dispersion in a velocity field, where the relative
two-point velocity scales according to 
and the
corresponding correlation time scales as 
, and
fix 
, as typical for turbulent flows. We show that two generic
types of dispersion behavior arize: For 
the
correlations in relative velocities decouple and the diffusion approximation
holds. In the opposite case, 
the relative motion is
strongly correlated. The case of Kolmogorov flows corresponds to a marginal,
nongeneric situation. In this case, depending on the particular parameters
of the flow, the dispersion behavior can be rather diffusive or rather
ballistic.
PACS: 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion / 47.27.Qb – Turbulent diffusion
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001
