Normal Shock Waves

Shock is a compression front across which the flow properties jump. In most practical applications, primary interest is not generally focused on the internal mechanism of the shock wave but on the net changes in fluid properties taking place across the wave. There is no heat added to or taken away from the flow as it traverses a shock wave, i.e. the flow process across the shock wave is adiabatic. The static pressure always increases across a shock wave; therefore, the shock can be visualized as a thermodynamic device which compresses the gas. With this consideration, the changes across a normal shock wave can be expressed purely in terms of thermodynamic variables, without explicit reference to a velocity or Mach number. The shock tube is a very useful research tool for investigating not only the shock phenomena but also the behavior of materials and objects when subjected to extreme conditions of pressure and temperature.