Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct numerical simulation of dispersed particles in a compressible
  fluid   We present a direct numerical simulation method for investigating the
dynamics of dispersed particles in a compressible solvent fluid. The validity
of the simulation is examined by calculating the velocity relaxation of an
impulsively forced spherical particle with a known analytical solution. The
simulation also gives information about the fluid motion, which provides some
insight into the particle motion. Fluctuations are also introduced by random
stress, and the validity of this case is examined by comparing the calculation
results with the fluctuation-dissipation theorem.

16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs