A Study of Shock Wave Formed in Unsteady Jet

Abstract

When a shock wave is discharged into the atmosphere from an open end of a pipe, a vortex ring is formed at the rim of the pipe end and goes downstream. In the process of vortex development a shock wave forms in the vortex ring. Small vortices generated at a jet boundary are sucked into the vortex ring and interact with the shock wave so that pressure waves, which are one of sources of noise, are scatterd. The formation of the shock wave does not only depend on Mach number of the discharged shock but also the strength of compression wave following the discharged shock. In order to analyze such a flow field the experimental study, i.e., optical visualization of the flow field is made at different Mach numbers or different strengths of compression wave. In this study the relation of the behavior of the downstream flow field with a profile of the pressure waves propagating in the pipe is discussed.