Pseudo-stationary oblique-shock-wave reflections in a polyatomic gas, sulfur hexafluoride

Pseudo-stationary oblique shock wave reflections in sulfur hexafluoride were investigated experimentally and numerically. Over 150 experiments were conducted in a 10 x 18 cm Hypervelocity Shock Tube in the range of incident shock wave Mach number 125 M subs 8.0 and wedge angle 4 deg theta sub w 47 deg with initial pressures P sub 0 ranging from 4 to 267 torr (0.53 to 35.60 KPa) and initial temperatures T sub 0 near 300 K. The four major types of shock wave reflection, i.e., regular reflection (RR), single Mach reflection (SMR), complex Mach reflection (CMR) and double Mach reflection (DMR), were observed. These were studied with infinite fringe interferograms using a 23 cm dia field of view Mach-Zehnder interferometer. The isopycnics obtained and the density distributions along the wedge surface are presented for the various reflection processes. Four experimental results in argon, air, carbon dioxide and sulfur hexafluoride with the same wedge angle and similar Mach numbers are compared.