A consistent and detailed account is presented concerning the causes of departure from ideal shock tube behaviour. Shock wave attenuation and other important attendant factors, caused by viscous action of the test fluid and boundary layer formation behind the shock, are surveyed critically, Emphasis is placed upon a consequence of boundary layer growth, namely, shock wave curvature. Usage is made of incident shock curvature theory to present a fundamental approach to reflected shock curvature. A Fourier series analysis is formed with subsequent addition of numerical analysis by computer utilisation. The study is made flexible in order to accept modifications aimed at increasing the accuracy of approximating the exact reflected shock curvature, and to describe the effects of other flow properties required for a consistent treatment of disturbed flow. Experimental verification by a schlieren optics procedure is attempted.