### Abstract

An approach for the generation of particles at a hybrid Navier-Stokes/DSMC interface is presented for simple gases and gas mixtures with internal degrees of freedom. DSMC particles generated at a hybrid boundary are assigned thermal velocities using a non-equilibrium surface reservoir approach, in which the fluxes of mass, momentum and energy determined from the Navier-Stokes solution are used to prescribe the appropriate velocity distribution function used in the DSMC particle generation. The non-equilibrium surface reservoir approach is first outlined for a simple (single-species, monatomic) gas, and is then extended to gas mixtures with internal degrees of freedom, in which additional diffusion and internal heat flux terms are included in the Generalized Chapman-Enskog formulation of the perturbation. The significance of the diffusion, shear stress and heat flux breakdown parameters used to compute the perturbation are examined at a hybrid interface within non-equilibrium boundary layer flow, as well as within the breakdown region near a normal shock, in a five-species air gas mixture. The validity of the Chapman-Enskog perturbation at each of these hybrid interfaces is assessed by comparison with the Generalized Chapman-Enskog perturbations. Although a hybrid flowfield solution is not presented, this work provides a rigorous approach for non-equilibrium particle generation involving general hybrid particle/continuum studies of hypersonic flows.

Original language | English (US) |
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Pages (from-to) | 468-481 |

Number of pages | 14 |

Journal | Journal of Computational Physics |

Volume | 232 |

Issue number | 1 |

DOIs | |

State | Published - Jan 1 2013 |

Externally published | Yes |

### Keywords

- Generalized Chapman-Enskog Theory
- Hybrid methods
- Non-equilibrium flows
- Particle generation

### ASJC Scopus subject areas

- Numerical Analysis
- Modeling and Simulation
- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)
- Computer Science Applications
- Computational Mathematics
- Applied Mathematics

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## Cite this

*Journal of Computational Physics*,

*232*(1), 468-481. https://doi.org/10.1016/j.jcp.2012.08.017