Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A simplification of the unified gas kinetic scheme   Unified gas kinetic scheme (UGKS) is an asymptotic preserving scheme for the
kinetic equations. It is superior for transition flow simulations, and has been
validated in the past years. However, compared to the well known discrete
ordinate method (DOM) which is a classical numerical method solving the kinetic
equations, the UGKS needs more computational resources. In this study, we
propose a simplification of the unified gas kinetic scheme. It allows almost
identical numerical cost as the DOM, but predicts numerical results as accurate
as the UGKS. Based on the observation that the equilibrium part of the UGKS
fluxes can be evaluated analytically, the equilibrium part in the UGKS flux is
not necessary to be discretized in velocity space. In the simplified scheme,
the numerical flux for the velocity distribution function and the numerical
flux for the macroscopic conservative quantities are evaluated separately. The
simplification is equivalent to a flux hybridization of the gas kinetic scheme
for the Navier-Stokes (NS) equations and conventional discrete ordinate method.
Several simplification strategies are tested, through which we can identify the
key ingredient of the Navier-Stokes asymptotic preserving property. Numerical
tests show that, as long as the collision effect is built into the macroscopic
numerical flux, the numerical scheme is Navier-Stokes asymptotic preserving,
regardless the accuracy of the microscopic numerical flux for the velocity
distribution function.

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The categories of this paper are: q-alg
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The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: supr-con
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The categories of this paper are: atom-ph
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The categories of this paper are: econ
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The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: math-ph
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The categories of this paper are: q-fin
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The categories of this paper are: q-bio