Area change effects on shock wave propagation.

Abstract

The work presented in this dissertation describes the effects that an area change has on shock wave propagation. Of particular interest is the analysis and optimisation of a gradual area reduction whereby a shock wave may be optimally strengthened. Experimental testing is conducted for a planar shock wave of A1s = 1.33 propagating through one of three cornpound parabolic profiles of 130, 195 or 260mm in length, all of which exhibit an 80% reduction in area. Experimental images were captured using an innovative colour schlieren setup for high- resolution images and lower resolution high-speed video. Results showed that there exists three main types of flow scenarios for propagation through a gradual area reduction, and an optimal net increase of 12.7% in shock Mach number was calculated for the longest profile of 260m.m which was predicted to within 5% theoretical predictions using Milton's (1975) modified CCW Relation.