Experimental study on the developing process of steady Blunt-Body supersonic flow in the shock tube and numerical simulation

Abstract

The goal of this study is to investigate the shock wave dynamics in the shock tube equipped with a supersonic nozzle block inside. Numerical simulation is first made using two-dimensional unsteady compressible Euler equation. AUSM+ upwind scheme is applied since it is known robust in the high mach number flows without entropy fixing. We need adaptive unstructured quadrilateral grids with the finite volume method and MUSCL approach. We consequently showed how the plane moving shock wave entering into a supersonic nozzle is changed to a steady bow shock wave in front of a blunt body in the shock tube. The nozzle contour was designed by Method Of Characteristics (MOC). Experimentally, helium is used to achieve high mach number shock wave, namely, $M_s=2.59$ in the present study. The high subsonic flow behind the moving shock wave is accelerated to a supersonic flow in the nozzle, impeding the reflection of moving shock wave from the blunt body. Steady bow shock wave is thus obtained after a brief transitional process. Shadowgraphy and a double-pulse holographic interferometry are used to visualize the shock tube flow converging to a steady supersonic flow in front of a two-dimensional blunt body having semi-circular head form and an aero-spike. Comparison with the computational result is presented. Good agreement is obtained.