Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An HLL Riemann solver for the hybridised discontinuous Galerkin
  formulation of compressible flows   This work proposes a high-order hybridised discontinuous Galerkin (HDG)
formulation of the Harten-Lax-Van Leer (HLL) Riemann solver for compressible
flows. A unified framework is introduced to present Lax-Friedrichs, Roe and HLL
Riemann solvers via appropriate definitions of the HDG numerical fluxes. The
resulting high-order HDG method with HLL Riemann solver is evaluated through a
set of numerical simulations of inviscid compressible flows in different
regimes, from subsonic isentropic flows to transonic and supersonic problems
with shocks. The accuracy of the proposed method is comparable with the one of
Lax-Friedrichs and Roe numerical fluxes in subsonic and transonic flows. The
superior performance of HLL is highlighted in supersonic cases, where the
method provides extra robustness, being able to produce positivity preserving
approximations without the need of any user-defined entropy fix.

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The categories of this paper are: physics
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The categories of this paper are: dg-ga
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The categories of this paper are: mtrl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat