Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonlinear superposition of direct and inverse cascades in
  two-dimensional turbulence forced at large and small scales   We inquire about the properties of 2d Navier-Stokes turbulence simultaneously
forced at small and large scales. The background motivation comes by
observational results on atmospheric turbulence. We show that the velocity
field is amenable to the sum of two auxiliary velocity fields forced at large
and small scale and exhibiting a direct-enstrophy and an inverse-energy
cascade, respectively. Remarkably, the two auxiliary fields reconcile universal
properties of fluxes with positive statistical correlation in the inertial
range.

17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg