The rarefaction effects on the supersonic lateral jet/freestream interaction

The reaction control system (RCS) relies on the interaction between the lateral jet and the freestream to achieve precise attitude control, quick response, and flexible flow field control in near space. However, these advantages in the continuum region will not be evident in rarefied flows. This paper utilizes direct simulation Monte Carlo (DSMC) to investigate the effects of rarefaction on the supersonic lateral jet/hypersonic freestream interaction over a flat plate and a wedge. Typical flow structures, such as vortical structures and shock waves, are observed in the continuous flow fields for both the flat-plate and wedge configurations. Additionally, a distinct bow shock similar to the Mach stem emerges in the flow field above the wedge, resulting from the interaction between the shock wave at the leading edge with a significant incident angle and the jet's bow shock wave. In rarefied flow fields, vortical structures downstream of the jet disappear, the shock wave thickens, and the distinct bow shock gradually diminishes. Three dimensionless interaction strength groups and the length of the interaction region, quantified by the wall pressure, shear stress, and heat flux, respectively, decrease exponentially with the global Knudsen number. Specifically, the interaction of the supersonic jet has the most significant impact on the increase in wall heat flux for both the flat-plate and wedge configurations.