Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exact coherent structures in a reduced model of parallel shear flow   A reduced description of shear flows consistent with the Reynolds number
scaling of lower-branch exact coherent states in plane Couette flow [J. Wang et
al., Phys. Rev. Lett. 98, 204501 (2007)] is constructed. Exact time-independent
nonlinear solutions of the reduced equations corresponding to both lower and
upper branch states are found for Waleffe flow [F. Waleffe, Phys. Fluids 9,
883--900 (1997)]. The lower branch solution is characterized by fluctuations
that vary slowly along the critical layer while the upper branch solutions
display a bimodal structure and are more strongly focused on the critical
layer. The reduced model provides a rational framework for investigations of
subcritical spatiotemporal patterns in parallel shear flows.

15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph