Receptivity of high-speed boundary layers in binary mixture of gases to kinetic fluctuations

The receptivity of high-speed boundary layers in Binary Mixture of gases (oxygen and nitrogen) to kinetic fluctuations (KF) is considered within the framework of fluctuating hydrodynamics. The formulation is based on the idea that KF-induced dissipative fluxes may lead to the generation of unstable modes in the boundary layer. The binary mixtures may serve as limiting cases for real gas effects in an airflow. It is assumed that KF manifest themselves in this context through “stochastic forcing” by a random stress tensor, a random heat flux, a random species diffusion, and a random chemical source term. The approach taken here follows that of Fedorov and Tumin (2017), but includes previously unconsidered effects such as fluctuating species diffusion and fluctuating species production. The results are in agreement with Fedorov and Tumin (2017) where it was shown that in the case of a calorically perfect gas, that boundary layer flow is most susceptible to kinetic fluctuations in the critical layer and that the fluctuations of the shear stress in the streamwise momentum equation are the dominant fluctuations.