Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constrained flow around a magnetic obstacle   Many practical applications exploit an external local magnetic field --
magnetic obstacle -- as an essential part of their constructions. Recently, it
has been demonstrated that the flow of an electrically conducting fluid
influenced by an external field can show several kinds of recirculation. The
present paper reports a 3D numerical study whose some results are compared with
an experiment about such a flow in a rectangular duct.

31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas