Comparison of Vibrational Relaxation Modeling for Strongly Non-Equilibrium Flows
SPECTRAL SCIENCES INC BURLINGTON MA
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The detailed description of the vibrational energy content is important for many gas flow processes including experimental gas measurement techniques, shock layer vibration-dissociation coupling, and vibrational energy freezing in strong expansions. Various vibrational relaxation models have been developed for use within the direct simulation Monte Carlo DSMC method. This study compares the Larsen-Borgnakke and Forced Harmonic Oscillator vibrational relaxation models through comparison with detailed quasi-classical trajectory QCT results for an atom-diatom system with focus on the effects of the form of the relaxation model. These QCT results have been extensively compared with measured data and provide a unique opportunity to evaluate these inelastic models. This work also compares the results from each model for a vibrationally exciting relaxation problem. Even when the two models have consistent vibrational collision numbers to match bulk temperature predictions for relaxation problems, the predicted evolution of the vibrational distribution function differs. This disagreement results in different prediction of radiative emission spectra.
- Fluid Mechanics
- Atomic and Molecular Physics and Spectroscopy