Pseudo-Stationary Oblique-Shock-Wave Reflections in a Polyatomic Gas - Sulfur Hexafluoride
TORONTO UNIV DOWNSVIEW (ONTARIO) INST FOR AEROSPACE STUDIES
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Pseudo-stationary oblique-shock-wave reflections in sulfur hexafluoride were investigated experimentally and numerically. Over 150 experiments were conducted in the UTIAS 10 x 18 cm Hypervelocity Shock Tube in the range of incident shock wave Mach number 1.25 M sub s 8.0 and wedge angle 4 deg theta sub w 47 deg with initial pressures P sub o ranging from 4 to 267 torr 0.53 to 35.60 kPa and initial temperatures T sub o 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 five 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. The analytical transition boundaries between the four types of shock-wave reflection were established up to M sub s 10.0 for frozen and vibrational equilibrium sulfur hexafluoride. The numerical results of the second triple-point system show that for a given incident shock Mach number, the highest pressure is achieved through a DMR instead of a RR. An application of reflections in pseudo-stationary flow to the interaction of spherical blast waves with a planar surface is shown and discussed.
- Fluid Mechanics