Stabilization of a supersonic boundary layer by an additive of a polyatomic vibrationally excited and dissociating gas

Based on a system of gas dynamics equations for a mixture of vibrationally excited chemically reacting molecular gases, the effect of a carbon dioxide additive on the stability of a hypersonic boundary layer of neutral nitrogen on a plate was studied. Calculations were performed for five variants of mixture composition. Steady-state flow parameters were calculated using a locally self-similar approximation of the boundary layer equations. Within the framework of linear stability theory, the dependences of the critical Reynolds numbers Re δc and the laminar-turbulent transition Reynolds numbers Re xT * on the molar concentration of the additive were obtained. In particular, for a 50% mixture, the relative increase in both criteria compared to the corresponding values for a mixture of perfect gases is approximately 53%. Moreover, the contribution of CO 2 dissociation to the shift of the laminar-turbulent transition zone is twice as great as the contribution of vibrational mode relaxation. It is shown that the obtained dependence of Re xT * on the molar concentration of the additive correlates with the corresponding experimental results of Professor H. Hornung’s group.