Experimental Investigation of a Hypersonic Inlet with and Without Sidewall Compression

The inlet of a Mach 8 cruise vehicle has been experimentally investigated in a hypersonic blow down wind tunnel with test times of up to 30s. Two test series have been carried out, the first one with a two-dimensional inlet configuration and the second one with the inlet featuring additional side-wall compression. The objective of the tests was to determine the performance of the inlet at on- and off-design conditions, i.e. at angle of attack and angle of yaw. Additionally, the starting behavior of the inlet has been determined, i.e. the contraction ratio at which the inlet starts. Results were interpreted from schlieren visualizations, IR thermography, static and Pitot pressure readings and mass flow measurements. The off-design investigation of both inlet configurations revealed the sensitivity of the inlet towards a cowl shock induced separation on the second compression ramp. If the cowl shock was not ensured to fall into the bleed duct behind the second ramp, no inlet flow could be established. The comparison of starting contraction ratios showed the advantage of the inlet with side-wall compression, i.e. the inlet with sidewall compression starts at higher contraction ratios.