Stability of the boundary layer of contoured M = 6 nozzle with local foreign gas injection

Abstract

The influence of foreign gas injection on the boundary layer stability of the Mach 6 nozzle of the Transit-M wind tunnel is investigated within the framework of the linear stability theory. The N-factors of the Görtler vortices and the first and second Mack modes are obtained. For a given nozzle, the most unstable disturbances are Görtler vortices. It is shown that the light gas injection leads to a significant slowdown in the growth of Görtler vortices, and the higher the mass flow rate, the stronger this effect. However, an increase in the mass flow rate of a light gas leads to an acceleration of the second mode growth in the boundary layer of M = 6 nozzle; the second mode can lead to a transition earlier than the Görtler vortices at some parameters of the injections. Heavy gas injection accelerates the growth of Görtler vortices and second mode disturbances. The growth of the first Mack mode is slower during the injection of both light and heavy gases.