Shock-wave strengthening by area convergence

A 17 in. diameter shock tube was coupled to a 1 in. tube by a 10° half-angle conical convergence. Timing measurements showed that the shock waves emerged from the convergence at 2–3 times their entrance speeds, and then decelerated downstream. After the application of a viscous correction, the shock speeds at the convergence exit agreed to within 5% with equilibrium real-gas calculations of the model of Chester (1954), Chisnell (1957) and Whitham (1958). The downstream deceleration, due to viscosity and to higher-order interactions not included in the theory, was also briefly studied.