Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unsteady flows and inhomogeneous packing in damp granular heap flows   We experimentally study the transition from steady flow to unsteady flow in a
quasi-2D granular heap when small amounts of water are added to monodisperse
glass spheres. Particles flow uniformly down both sides of the heap for low
water content, but unsteady flow occurs as the water content increases. The
unsteady flow mode consists of a non-depositing downslope avalanche and an
upslope propagating granular jump. The transition from steady to unsteady flow
occurs when the slope exceeds a critical angle as a result of water-induced
cohesion. Under unsteady flow conditions, the deposited heap consists of
loosely packed and densely packed layers, the formation of which is closely
related to the unsteady flow dynamics.

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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: atom-ph
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The categories of this paper are: eess
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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The categories of this paper are: astro-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics