UNSTEADY CHARACTERISTICS OF A HYPERSONIC TYPE-IV SHOCK INTERACTION

The unsteady characteristics of a Mach 8 type IV shock interaction are numerically studied using a time-accurate total variation diminishing scheme for solving the thin layer approximation to the two-dimensiona l Navier-Stokes equations in conservative form. The calculations show that the peak surface pressure, the impingement location of the supers onic jet, and the time required for the development of the interaction are strong functions of the impinging shock location. For a range of impinging shock locations the interaction is found to be unsteady. In addition, this unsteady phenomena is shown to be related to the transi ents of the interaction and to the orientation of the terminating shoc k associated with the supersonic jet. The frequency of oscillation of the supersonic jet, as described by the location of the peak surface p ressure, is shown to be proportional to the location of the impinging shock.