Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct and inverse energy cascades in a forced rotating turbulence
  experiment   We present experimental evidence for a double cascade of kinetic energy in a
statistically stationary rotating turbulence experiment. Turbulence is
generated by a set of vertical flaps which continuously injects velocity
fluctuations towards the center of a rotating water tank. The energy transfers
are evaluated from two-point third-order three-component velocity structure
functions, which we measure using stereoscopic particle image velocimetry in
the rotating frame. Without global rotation, the energy is transferred from
large to small scales, as in classical three-dimensional turbulence. For
nonzero rotation rates, the horizontal kinetic energy presents a double
cascade: a direct cascade at small horizontal scales and an inverse cascade at
large horizontal scales. By contrast, the vertical kinetic energy is always
transferred from large to small horizontal scales, a behavior reminiscent of
the dynamics of a passive scalar in two-dimensional turbulence. At the largest
rotation rate the flow is nearly two-dimensional, and a pure inverse energy
cascade is found for the horizontal energy. To describe the scale-by-scale
energy budget, we consider a generalization of the K\'arm\'an-Howarth-Monin
equation to inhomogeneous turbulent flows, in which the energy input is
explicitly described as the advection of turbulent energy from the flaps
through the surface of the control volume where the measurements are performed.

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The categories of this paper are: nucl-th
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: funct-an
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: bayes-an
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The categories of this paper are: q-bio
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The categories of this paper are: math
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The categories of this paper are: gr-qc
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The categories of this paper are: ao-sci