Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Logarithmic temperature profiles of turbulent Rayleigh-B\'enard
  convection in the classical and ultimate state for a Prandtl number of 0.8   We report on experimental determinations of the temperature field in the
interior (bulk) of turbulent Rayleigh-Benard convection for a cylindrical
sample with aspect ratio (diameter over height) of 0.50, both in the classical
and in the ultimate state. The Prandtl number was close to 0.8. We find a
"logarithmic layer" in which the temperature varies as A*ln(z/L) + B with the
distance z from the bottom plate of the sample. The amplitude A varies with
radial position r. In the classical state these results are in good agreement
with direct numerical simulations (DNS); in the ultimate state there are as yet
no DNS. A close analogy between the temperature field in the classical state
and the "Law of the Wall" for the time-averaged down-stream velocity in shear
flow is discussed.

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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: atom-ph
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The categories of this paper are: mtrl-th
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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: q-fin
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The categories of this paper are: cmp-lg