Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: DNS of horizontal open channel flow with finite-size, heavy particles at
  low solid volume fraction   We have performed direct numerical simulation of turbulent open channel flow
over a smooth horizontal wall in the presence of finite-size, heavy particles.
The spherical particles have a diameter of approximately 7 wall units, a
density of 1.7 times the fluid density and a solid volume fraction of 0.0005.
The value of the Galileo number is set to 16.5, while the Shields parameter
measures approximately 0.2. Under these conditions, the particles are
predominantly located in the vicinity of the bottom wall, where they exhibit
strong preferential concentration which we quantify by means of Voronoi
analysis and by computing the particle-conditioned concentration field. As
observed in previous studies with similar parameter values, the mean streamwise
particle velocity is smaller than that of the fluid. We propose a new
definition of the fluid velocity "seen" by finite-size particles based on an
average over a spherical surface segment, from which we deduce in the present
case that the particles are instantaneously lagging the fluid only by a small
amount. The particle-conditioned fluid velocity field shows that the particles
preferentially reside in the low-speed streaks, leading to the observed
apparent lag. Finally, a vortex eduction study reveals that spanwise particle
motion is significantly correlated with the presence of vortices with the
corresponding sense of rotation which are located in the immediate vicinity of
the near-wall particles.

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The categories of this paper are: q-bio
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The categories of this paper are: nucl-ex
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The categories of this paper are: supr-con
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The categories of this paper are: chao-dyn
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
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The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: hep-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-th
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The categories of this paper are: cs
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The categories of this paper are: solv-int
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The categories of this paper are: adap-org