Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A pressure-based method for weakly compressible two-phase flows under a
  Baer-Nunziato type model with generic equations of state and pressure and
  velocity disequilibrium   Within the framework of diffuse interface methods, we derive a pressure-based
Baer-Nunziato type model well-suited to weakly compressible multiphase flows.
The model can easily deal with different equation of states and it includes
relaxation terms characterized by user-defined finite parameters, which drive
the pressure and velocity of each phase toward the equilibrium. There is no
clear notion of speed of sound, and thus, most of the classical low Mach
approximation cannot easily be cast in this context. The proposed solution
strategy consists of two operators: a semi-implicit finite-volume solver for
the hyperbolic part and an ODE integrator for the relaxation processes. Being
the acoustic terms in the hyperbolic part integrated implicitly, the stability
condition on the time step is lessened. The discretization of non-conservative
terms involving the gradient of the volume fraction fulfills by construction
the non-disturbance condition on pressure and velocity to avoid oscillations
across the multimaterial interfaces. The developed simulation tool is validated
through one-dimensional simulations of shock-tube and Riemann-problems,
involving water-aluminum and water-air mixtures, vapor-liquid mixture of water
and of carbon dioxide, and almost pure flows. The numerical results match
analytical and reference ones, except some expected discrepancies across
shocks, which however remain acceptable (errors within some percentage points).
All tests were performed with acoustic CFL numbers greater than one, and no
stability issues arose, even for CFL greater than 10. The effects of different
values of relaxation parameters and of different amount equations of state --
stiffened gas and Peng-Robinson -- were investigated.

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The categories of this paper are: astro-ph
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The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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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: comp-gas
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The categories of this paper are: patt-sol
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
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The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an