Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamics of reversals and condensates in 2D Kolmogorov flows   We present direct numerical simulations of the different two-dimensional flow
regimes generated by a constant spatially periodic forcing balanced by viscous
dissipation and large scale drag with a dimensionless damping rate $1/Rh$. The
linear response to the forcing is a $6\times6$ square array of counter-rotating
vortices, which is stable when the Reynolds number $Re$ or $Rh$ are small.
After identifying the sequence of bifurcations that lead to a spatially and
temporally chaotic regime of the flow when $Re$ and $Rh$ are increased, we
study the transitions between the different turbulent regimes observed for
large $Re$ by varying $Rh$. A large scale circulation at the box size (the
condensate state) is the dominant mode in the limit of vanishing large scale
drag ($Rh$ large). When $Rh$ is decreased, the condensate becomes unstable and
a regime with random reversals between two large scale circulations of opposite
signs is generated. It involves a bimodal probability density function of the
large scale velocity that continuously bifurcates to a Gaussian distribution
when $Rh$ is decreased further.

30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio