Characteristics of Free Supersonic Jets Exhausting Into Quiescent Air

An experimental study was conducted of the spreading and axial decay of free supersonic jets exhausting into quiescent air. This work involved the measurement of total pressures and temperatures downstream of two supersonic heated-air jets and three types of solid-propellant rockets. Conclusions are drawn as to velocity, pressure, and temperature distributions downstream from the free, supersonic jet. Notable conclusions are: (a) nondimensional velocity and temperature profiles are similar for both the heated-air jet and the rockets; and (b) after the free supersonic jet decays to the sonic point, it can be treated as a normal shock-free parallel flow jet.