Handbook of Compressible Aerodynamics

Chapter 23

Shock Tube

23.1. General theory

The shock tube is a simple way to achieve supersonic flows with elevated pressure and temperature levels (several thousands of kelvins for the temperature). The shock tube and its variants, such as the shock tunnel, are used to simulate hypersonic flows, which are distinguished by high stagnation enthalpy. The energy to expend to operate a shock tube is modest or low. Accordingly, and in return, the time during which a useful flow is established is very short: a few milliseconds to a few hundred microseconds. The shock tube is also used in detonics (to study conditions of shock wave formation during an explosion) and to investigate the phenomena resulting from the propagation and reflection of shocks, for example, the creation and propagation of the shock produced by a high-speed train entering a tunnel. Shock tubes are also used for the analysis of fast processes involved in chemical reactions, in particular, chemical kinetics.

A shock tube consists of a cylindrical tube, with a circular or square section, closed at both ends, and divided into two compartments initially isolated from each other (see Figure 23.1). The low-pressure compartment contains a gas with the pressure p₁ and temperature T₁. This gas is called driven gas. The high-pressure compartment is filled with a gas at high pressure p₄ (several hundreds or even thousands of atmospheres), and the temperature T₄ (often close to T₁). This gas is called the driver gas. The low-pressure ...