An Investigation of Starting Processes and Flow Patterns Occurring in Hypersonic Axisymmetric Inlets of Internal Compression

Results of numerical computations of supersoni flow patterns in axisymmetric inlets with the internal compression of the airstream captured by them are presented. The simplest inlets in the form of conical funnels were under consideration. The characteristic feature of supersonic flows in these inlets is the formation of an initial longitudinally-curved shock wave with intensity increasing downstream and toward the flow axis, which is finalized by the generation of a triple-shock configuration including the initial incident shock wave, a central Mach disk, and a reflected shock wave. Conditions of forming these flows were investigated depending on the freestream Mach number, angle of the internal cone wall, and relative cross-sectional area of the inlet throat. A range of the freestream Mach number M = 2-12 was covered. There were determined the throat area required for the inlet starting and that minimal throat area at which the supersonic inflow into the started inlet still possible. An analysis of starting conditions of some axisymmetric inlets of internal compression tested at M = 7.5-11.5 in hot-shot wind tunnels was fulfilled. Firstly, data of these inlets tests were compared with data of numerical computations of flows in them carried out with the use of the pseudo-unsteady method for simulation of inviscid, laminar, and turbulent flows. Secondly, there was solved a problem on evolution of the unsteady turbulent flow forming in a common process of starting a hot-shot wind tunnel and a funnelshaped inlet tested in it.