Investigation of the Flow and Drag Due to Supersonic Jets Discharging Upstream into a Supersonic Flow

摘要

The flow generated by a supersonic jet issuing from the nose of a blunt body upstream in a supersonic flow can fall into two typical classes: (1) a steady flow characterized by a shock layer between two strong shocks, one terminating the jet and the other the free stream, and located at a well determined, relatively short stand-off distance upstream from the nose, and (2) an unsteady flow resembling a jet-spike which penetrates relatively far into the free stream and deflects it through oblique shocks. Shock standoff distances in blunt-interaction flow can be predicted theoretically with considerable accuracy. The limits of existence of this type of interaction can be calculated if empirical evaluations of two parameters appearing in the analytical formulation are supplied. The available experiments yield a first estimate of these parameters but additional data and further refinement of the analysis are needed to obtain a satisfactorily precise correlation.