Stabilization of the initial region of a two-dimensional supersonic nitrogen jet at various values of the nozzle exit-to-ambient pressure ratio

Interferometry was used to study the stabilization of the quasi-steady structure of the flow in the initial region of a pulsed supersonic nitrogen jet issuing from a plane wedge-shaped nozzle for a wide range of nozzle exit-to-ambient pressure ratios (0.74-1200). Measurements results are analyzed: (1) the velocity of the initial shock wave in three directions; (2) time variations of density near the nozzle section; and (3) total pressure in the flow symmetry plane. It is found that as the above-mentioned ratio decreases from 1000 to 1.3 the time of stabilization goes from 300 microsec to 1 microsec.