Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $^4$He Counterflow Differs Strongly from Classical Flows: Anisotropy on
  Small Scales   Three-dimensional anisotropic turbulence in classical fluids tends towards
isotropy and homogeneity with decreasing scales, allowing --eventually-- the
abstract model of "isotropic homogeneous turbulence" to be relevant. We show
here that the opposite is true for superfluid $^4$He turbulence in
3-dimensional counterflow channel geometry. This flow becomes less isotropic
upon decreasing scales, becoming eventually quasi 2-dimensional. The physical
reason for this unusual phenomenon is elucidated and supported by theory and
simulations.

15
The categories of this paper are: nucl-ex
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The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: physics
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The categories of this paper are: stat
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The categories of this paper are: hep-th
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The categories of this paper are: bayes-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat