Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Velocity, Velocity Gradient and Vorticity Statistics of Grid Turbulence
  Obtained Using Digital Cross-correlation PIV   Grid turbulence is investigated using cross-correlation digital Particle
Image Velocimetry (PIV) over a range of Taylor Reynolds Number (Re{\lambda})
from 5 to 44. Instantaneous velocity is measured directly and vorticity and
velocity gradients are obtained indirectly. Measurements are taken at various
downstream locations from the generating grid. Probability distribution
functions (PDFs) are calculated for the fluctuating component of the velocity,
the spatial velocity gradients and vorticity. The PDF of the velocity
fluctuations has a Gaussian distribution while velocity gradients and vorticity
are found to have non-Gaussian PDF distributions. The structure of the flow is
investigated by calculating spatial autocorrelations for all measured and
derived data. The spatial velocity autocorrelations differ from previous
experimental measurements of grid turbulence, most of which have been
determined from single-point measurements. This difference is believed to be
due to differences in the way in which the measurements are made, and
particularly to differences in the spatial size of the experimental domain.

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The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat
5
The categories of this paper are: gr-qc
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The categories of this paper are: eess
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The categories of this paper are: adap-org
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The categories of this paper are: astro-ph
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph