Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Shocks in Vertically Oscillated Granular Layers   We study shock formation in vertically oscillated granular layers, using both
molecular dynamics simulations and numerical solutions of continuum equations
to Navier-Stokes order. A flat layer of grains is thrown up from an oscillating
plate during each oscillation cycle and collides with the plate later in the
cycle. The collisions produce layer compaction near the plate and a high
temperature shock front that rapidly propagates upward through the layer. The
shock is highly time-dependent, propagating through the layer in only a quarter
of the cycle. We compare numerical solutions of the continuum equations to
molecular dynamics simulations that assume binary, instantaneous collisions
between frictionless hard spheres. The two simulations yield results for the
shock position, shape, and speed that agree well. An investigation of the
effect of inelasticity shows that the shock velocity increases continuously
with decreasing inelasticity; the elastic limit is not singular.

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The categories of this paper are: gr-qc
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The categories of this paper are: physics
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The categories of this paper are: q-fin
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The categories of this paper are: nlin
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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: q-alg
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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: astro-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: adap-org
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The categories of this paper are: solv-int
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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: q-bio