Experimental investigation of a generic three-dimensional sidewall compression scramjet inlet at Mach 10

Three-dimensional sidewall-compression scramjet inlets with leading-edge sweeps of 30 and 70 have been tested in the Langley Hypersonic CF4 Tunnel at Mach 6 with a ratio of speci c heats of 1.2. The parametric e ects of leading-edge sweep, cowl position, contraction ratio, and Reynolds number were investigated. The models were instrumented with 42 static pressure ori ces that were distributed on the sidewalls, baseplate, and cowl. Schlieren movies were made of selected tunnel runs for ow visualization of the entrance plane and cowl region. Although these movies could not show the internal ow, the e ect of the internal ow spillage on the external ow was evident. To obtain an approximate characterization of the ow eld, a modi cation to twodimensional, inviscid, oblique shock theory was derived to accommodate the three-dimensional e ects of leading-edge sweep. This theory qualitatively predicted the re ected shock structure (i.e., sidewall impingement locations) and the observed increase in spillage with increasing leading-edge sweep. The primary e ect of moving the cowl forward was capturing the ow that would have otherwise spilled ahead of the cowl. Increasing the contraction ratio (moving the sidewalls closer together) increases the number of internal shock re ections and hence incrementally increases the sidewall pressure distribution. Signi cant Reynolds number e ects were noted over a small range of Reynolds number.