Mesoflap and Bleed Flow Control for a Mach 2 Inlet

Abstract

Wind tunnel experiments were performed with a twodimensional external-compression inlet at Mach 2 to investigate the ability of aeroelastic mesoflaps to control a normal shock-wavehoundary-layer interaction at design conditions. The inlet was designed to have two oblique shocks and a terminal normal shock followed by a subsonic diffuser, with a rectangular cross-section throughout. The flow control system was applied to the normal shock-wave interaction with the ramp surface boundary layer. The flow control concept involves placing a streamwise array of mesoflaps beneath the shock interaction, and allowing highpressure air from the flow downstream of the shock wave to recirculate through a cavity below the flaps into the lowpressure flow upstream of the shock wave. The experiments were conducted with a two-dimensional inlet at the NASA Langley supersonic Unitary Plan Wind Tunnel (UPWT). The diagnostics included static pressure surveys over the cowl and ramp surfaces, schlieren images of the flow, and stagnation pressure distributions in the subsonic region downstream of the throat. The mesoflap flow control was compared to that of a conventional (aspirated) bleed system as well as a solid surface (no-control) configuration, with respect to various inlet performance parameters. The results show that the mesoflaps do provide an improvement in pressure recovery over the solid wall case, but also that the current mesoflaps were not optimized for the inlet configuration. In contrast, the bleed case showed a modest increase in pressure recovery but at a substantial mass-flow penalty.