Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relative periodic orbits in transitional pipe flow   A dynamical system description of the transition process in shear flows with
no linear instability starts with a knowledge of exact coherent solutions,
among them travelling waves (TWs) and relative periodic orbits (RPOs). We
describe a numerical method to find such solutions in pipe flow and apply it in
the vicinity of a Hopf bifurcation from a TW which looks to be especially
relevant for transition. The dominant structural feature of the RPO solution is
the presence of weakly modulated streaks. This RPO, like the TW from which it
bifurcates, sits on the laminar-turbulent boundary separating initial
conditions which lead to turbulence from those which immediately relaminarise.

16
The categories of this paper are: stat
2
The categories of this paper are: math
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph