@article{3734c96f3655469e83d2c996a6eac8a8,

title = "Evaluation of the Vibrational Relaxation Time for Air Components Based on the FHO and FHO-FR Models",

abstract = "Abstract: Various theoretical methods for calculating the vibrational relaxation time of air components are proposed. An accurate forced harmonic oscillator (FHO) model, as well as its advanced modification taking into account free molecular rotations (FHO-FR) are implemented to calculate the state-to-state vibrational energy transition rate coefficients. Due to the high computational complexity of the FHO-FR model, its direct use in nonequilibrium gas dynamic problems is prohibitively expensive. Therefore, an effective regression model, FHO-FR-reg, is proposed. It accurately approximates the energy exchange rate coefficients calculated using the original FHO-FR model, with a maximum error of less than 2%. The high computational efficiency of the FHO-FR-reg regression model is demonstrated. For N2–N, N2–O, N2–N2, O2–N, O2–O, O2–O2, NO–N, NO–O, NO–NO, O2–N2, and N2–O2 collisions, the relaxa