Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Clustering and relative velocities of heavy particles under
  gravitational settling in isotropic turbulent flows   Spatial clustering and intermittency in the relative velocity of heavy
particles of the same size settling in turbulent flows can be strongly affected
by gravity. We present a model for the timescale of the fluid velocity gradient
seen by particle pairs and propose an effective Kubo number based on this
timescale to explain the mechanism of gravity-enhanced clustering. We explore
the mechanisms of the gravity-induced reduction or enhancement of the
intermittency in the particle radial relative velocity (RRV) at different
Stokes numbers based on backward-in-time relative dispersion and preferential
sampling of the fluid field. These effects of gravity on clustering and the RRV
must be parameterized in the geometric collision kernel.

17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an