Nonstationary oblique-shock-wave reflections in air

The interferometric investigation of oblique-shock-wave reflections in air was conducted in the UTIAS 10 cm x 18 cm shock tube over steel wedges. The range of the incident shock Mach numbers M sub s was 1.1 or = M sub s or = 14.6. The wedge angle theta sub w ranged over 2 deg or = theta sub w or = 63.4 deg. Under these conditions it was possible to observe the four major types of nonstationary oblique-shock-wave reflections, i.e., regular reflection, single-Mach reflection, complex-Mach reflection, and double-Mach reflection. These were studied in air using finite and infinite-fringe techniques. The initial pressures of the experiments P sub 0 ranged from 0.67 (5) or = P sub 0 or = 101.33 (760) kPa (torr) and were conducted at room temperature, near 300 K. Where possible the initial pressures were kept as high as practicable to provide more numerous and detailed isopycnics of the flow fields. The new isopycnic data were compared with previous experimental results in nitrogen and several existing numerical simulations. Several cases in argon were considered as well. There is little doubt that numerical methods must be further improved to keep pace with the experimental results. A series of experiments was performed measuring the pressure history on and above the surface of a 40 deg wedge for several initial conditions. Along with the interferometric data these measurements provide insight into the complex flow fields observed in these experiments.