Numerical Analysis of Unsteady Nozzle Flow Induced by Shock Wave

Abstract

The unsteady starting process of an axisymmetric hypersonic nozzle in a conventional reflected-type shock tunnel has been simulated with an inviscid flow model using an upwind TVD scheme. In addition, the bursting process of a secondary diaphragm mounted at the shock tube end wall has been numerically reproduced in a time-accurate manner. The effects of initial nozzle pressure and incident shock strength on the nozzle starting time and propagation behavior of shock wave systems have been investigated. The results show a formation mechanism of a rearward-facing secondary shock wave and the behavior of shock waves and contact surface propagating in a convergent-divergent nozzle. Some of the results indicate that the shape distortion of a secondary shock wave severely delays the establishment of a quasi-steady flow under certain calculation conditions.