Numerical investigations of transient flow behaviour in a shock tunnel

Abstract

This work presents a computational study carried out to examine the velocity profile in high speed flow shock tunnel. A two-dimensional time accurate Navier-Stokes solver, which was programmed, based on the dimensions and configuration of a high speed test facility recently developed in Universiti Tenaga Nasional (UNITEN), Malaysia was applied. The solver uses second order accurate cell-vertex finite volume spatial discretization and fourth-order accurate Runge-Kutta temporal integration. The characteristics of the flow process were investigated along the whole facility for a selected pressure ratio, whereby special attention was paid to investigate the velocity profile histories in three significant sections of the shock tunnel. The shock wave motion, reflection and interaction with the contact surface were investigated and their influence on the performance of the shock tunnel was determined. The results show that the shock wave speed is highly influenced by the pressure ratio between the driver and driven sections and by its location along the facility. Simulation results also show that the flow is symmetrical before shock reflection but becomes asymmetrical just after the shock reflection. The flow within the nozzle section was found to be in a steady-state condition for a few milliseconds.