Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effects of Diffuse and Collimated Beam Radiation on a Symmetrical
  Cooling Case of Natural Convection   In the present work, the effects of diffuse and collimated radiation on the
symmetrical cooling case of natural convection in a two-dimensional cavity
heated from the bottom have been investigated, numerically. The cavity is
convectively heated from the bottom with heat transfer coefficient of 50 W/m2K
and free stream temperature 305 K, while both vertical walls of cavity are
isothermal at temperature of 296 K. The top wall is adiabatic and all walls are
opaque for radiation heat transfer. For collimated case, a small
semitransparent window of non-dimensional width of 0.05 at height of 0.7 has
been created on the left wall and a collimated irradiation of value 1000 W/m2
at an angle 45 is applied on this semitransparent window. The results reveal
that the diffuse radiation has little effect on the dynamics of two rolls
inside the cavity, however, collimated beam irradiation changes the dynamics of
two rolls significantly and also the heat transfer characteristics. This
further changes with the optical thickness of the fluid. The left vortex is
bigger in size than the right vortex for collimated beam in transparent fluid,
whereas, reverse trend is seen for collimated beam in non-zero optical
thickness of the fluid.

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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: plasm-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
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The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: alg-geom
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The categories of this paper are: q-alg
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: math
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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: stat