Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Dynamics of propagating turbulent pipe flow structures. Part I: Effect
  of drag reduction by spanwise wall oscillation
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat