The Impact of Injected Fluid Properties on Supersonic Flow

The injection of fluids into supersonic crossflow is a canonical problem of interest in flows applicable to attitude control systems and combustion devices. In these applications, understanding the trajectory of the injected fluid and its impact on the core flow is critically important. Due to the higher Mach number of the crossflow and its enthalpy, the generation of shock structures, stagnation points, and recirculation zones around the injection region can lead to complex flow physics. In particular, the role of the compressibility of the injected fluid on the evolution of these flow structures is not fully understood. The focus of this work is to leverage the notion of flow blockage to assess how the compressibility of the injected fluid creates these flow structures. Gaseous and liquid injection are considered, as well as a cylindrical solid obstruction and an equivalent solid convex hull. The stand-off distance and width of the bow shock generated at the leading edge of the injected fluid are employed to compare the capabilities of the obstructions in mitigating the effects of the crossflow. Detailed analyses of the predominant flow features are presented.