Aliat A, Vedula P, Josyula E
School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, Oklahoma 73019, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 Feb;83(2 Pt 2):026308. doi: 10.1103/PhysRevE.83.026308. Epub 2011 Feb 22.
In this paper a simple model is proposed for computation of rate coefficients related to vibration-translation transitions based on the forced harmonic oscillator theory. This model, which is developed by considering a quadrature method, provides rate coefficients that are in very good agreement with those found in the literature for the high temperature regime (≳10,000 K). This model is implemented to study a one-dimensional nonequilibrium inviscid N(2) flow behind a plane shock by considering a state-to-state approach. While the effects of ionization and chemical reactions are neglected in our study, our results show that multiquantum transitions have a great influence on the relaxation of the macroscopic parameters of the gas flow behind the shock, especially on vibrational distributions of high levels. All vibrational states are influenced by multiquantum processes, but the effective number of transitions decreases inversely according to the vibrational quantum number. For the initial conditions considered in this study, excited electronic states are found to be weakly populated and can be neglected in modeling. Moreover, the computing time is considerably reduced with the model described in this paper compared to others found in the literature.
本文基于受迫谐振子理论提出了一个用于计算与振动-平动跃迁相关的速率系数的简单模型。该模型通过考虑一种求积方法而开发，所提供的速率系数与文献中高温区域（≳10,000 K）的结果非常吻合。通过考虑态-态方法，该模型被用于研究平面激波后一维非平衡无粘N₂流。虽然在我们的研究中忽略了电离和化学反应的影响，但我们的结果表明，多量子跃迁对激波后气流宏观参数的弛豫有很大影响，特别是对高能级的振动分布。所有振动态都受多量子过程影响，但跃迁的有效数量根据振动量子数成反比减少。对于本研究中考虑的初始条件，发现激发电子态的粒子数很少，在建模中可以忽略。此外，与文献中其他模型相比，本文所述模型的计算时间大大减少。
