AN EXPERIMENTAL INVESTIGATION OF THE FLOW IN AN AXISYMMETRIC INTERNAL-COMPRESSION INLET FOR M = 2. 75

摘要

An experimental investigation was undertaken tp obtain detailed pressure measurements in the flow field and boundary-layer regions in the supersonic portion of an axisymmetric, internal-compression inlet. The inlet had a translatable centerbody, a contraction ratio of O.48 and a fineness ratio of 2. The tests were conducted at a free-stream Mach number of 2.75 for Reynolds numbers (based on inlet capture diameter) between 3.1 and 4.6 million.nFrom the experimental results obtained in the flow field the shock waves and vortex sheets were located and the patterns formed by these disturbances were constructed. The shock-wave pattern indicated coalescence of the annulus and centerbody shock waves near the inlet throat. The vortex pattern was in part incomplete because these disturbances were difficult to locate from the survey data. The surface-pressure data showed peaks in pressure on the centerbody immediately downstream of shock-wave impingements. It was not clear, however, if these peaks were associated with shock-wave boundary-layer interaction-or with the inviscid flow alone.nThe velocity profiles indicated the boundary layer to be turbulent. Upstream of any interaction with a shock wave the velocity profiles were similar, indicating the boundary layer to be in equilibrium. Interactions with shock waves distorted the velocity profile and thus equilibrium was not maintained across these interactions. Between interactions there was some evidence that the boundary layer was again in equilibrium.nThe boundary-layer growth within the inlet was estimated with the aid of the experimentally determined Mach number distributions and shock-wave locations. Two methods were used which were similar except that one treated the effects of the shock-wave interactions analytically and the other, empirically. In general, the estimates were reasonably accurate upstream of any interaction with a shock wave where the two methods were identical. Downstream of interactions with shock waves the methods were not so accurate but using an empirical relationship for the effects of interactions provided somewhat better results.