Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The effects of a compressive velocity pulse on a collapsing turbulent
  clump   High-resolution hydrodynamical simulations are presented to follow the
gravitational collapse of a uniform turbulent clump, upon which a purely radial
compressive velocity pulse is activated in the midst of the evolution of the
clump, when its turbulent state has been fully developed. The shape of the
velocity pulse is determined basically by two free parameters: the velocity
$V_0$ and the initial radial position $r_0$. In the present paper, models are
considered in which the velocity $V_0$ takes the values 2, 5, 10, 20, and 50
times the speed of sound of the clump $c_0$, while $r_0$ is fixed for all the
models. The collapse of the model with $2 \, c_0$ goes faster as a consequence
of the velocity pulse, while the cluster formed in the central region of the
isolated clump mainly stays the same. In the models with greater velocity
$V_0$, the evolution of the isolated clump is significantly changed, so that a
dense shell of gas forms around $r_0$ and moves radially inward. The radial
profile of the density and velocity as well as the mass contained in the dense
shell of gas are calculated, and it is found that (i) the higher the velocity
$V_0$, the less mass is contained in the shell; (ii) there is a critical
velocity of the pulse, around $10 \, c_0$, such that for shock models with a
lower velocity, there will be a well defined dense central region in the
shocked clump surrounded by the shell.

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The categories of this paper are: math-ph
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: nlin
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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
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The categories of this paper are: cond-mat
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The categories of this paper are: bayes-an
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: mtrl-th
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: dg-ga