Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Turbulent pair dispersion of inertial particles   The relative dispersion of pairs of inertial particles in incompressible,
homogeneous, and isotropic turbulence is studied by means of direct numerical
simulations at two values of the Taylor-scale Reynolds number $Re_{\lambda}
\sim 200$ and 400. The evolution of both heavy and light particle pairs is
analysed at varying the particle Stokes number and the fluid-to-particle
density ratio. For heavy particles, it is found that turbulent dispersion is
schematically governed by two temporal regimes. The first is dominated by the
presence, at large Stokes numbers, of small-scale caustics in the particle
velocity statistics, and it lasts until heavy particle velocities have relaxed
towards the underlying flow velocities. At such large scales, a second regime
starts where heavy particles separate as tracers particles would do. As a
consequence, at increasing inertia, a larger transient stage is observed, and
the Richardson diffusion of simple tracers is recovered only at large times and
large scales. These features also arise from a statistical closure of the
equation of motion for heavy particle separation that is proposed, and which is
supported by the numerical results. In the case of light particles with high
density ratios, strong small-scale clustering leads to a considerable fraction
of pairs that do not separate at all, although the mean separation increases
with time. This effect strongly alters the shape of the probability density
function of light particle separations.

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The categories of this paper are: cs
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The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
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The categories of this paper are: econ
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The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
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The categories of this paper are: math
24
The categories of this paper are: dg-ga
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The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
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The categories of this paper are: adap-org
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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
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The categories of this paper are: funct-an