Kinetic and Continuum Modeling of High-Temperature Air Relaxation

Sergey F. Gimelshein, Ingrid J. Wysong, Alexander J. Fangman, Daniil A. Andrienko, Olga V. Kunova, Elena V. Kustova, Kyle M. Hanquist, Fabio Morgado, Catarina Garbacz, Marco Fossati

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Fully kinetic, vibrationally kinetic, and continuum solvers with varying model fidelity are used in this work to model the high-temperature relaxation of air in 7230 and 15,000 K adiabatic heat baths and a 6 km∕s hypersonic flow over a cylinder. The results show significant impact of uncertainties in vibrational relaxation times and reaction rate constants on thermal and chemical relaxation, in particular, on gas temperature and species mole fractions. Most notably, these uncertainties need to be reduced for collisions that include nitric oxide. Order-of-magnitude differences in the nitric oxide dissociation and recombination rates have a large impact on the peak NO mole fraction immediately behind the shock and surface-distributed heat flux, respectively. High-fidelity kinetic and continuum approaches are found to have different reaction channels having the largest effect on species mole fractions and gas temperature: N2 O exchange and O2 O dissociation in the former, and NO O and O2 N2 dissociation in the latter.

Original languageEnglish (US)
Pages (from-to)870-893
Number of pages24
JournalJournal of Thermophysics and Heat Transfer
Issue number4
StatePublished - Oct 2022

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Aerospace Engineering
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes
  • Space and Planetary Science


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