Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First principle basis of the direct numerical simulation for turbulence
  of inert and reactive gases   An open question of whether phenomenological fluid equations to be used for
direct numerical simulation of turbulence are warranted on `first principles'
is addressed, and the problem is posed using Klimontovich microscopic density
to replace the Boltzmann function of the classical statistical mechanics. For
inert monatomic gases, it is shown that all the gasdynamic equations, namely,
the three conservation equations plus the Navier-Stokes stress law and the
Fourier heat conduction law are retrieved as governing instantaneous
quantities, without having recourse to any concepts of averaging or statistical
equilibrium. For reactive gases, however, the Arrhenius reaction rate law
written in terms of the fluctuating temperature is not justified, reflecting
the fact that this rate law hinges crucially on these concepts.

30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs