Area change effects on shock wave propagation.
Date
2014-02-17
Authors
Dowse, Jonathan Neil.
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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.