Interferometric Techniques and Data Evaluation Methods for the UTIAS 10 cm x 18 cm Hypervelocity Shock Tube

Abstract

NOf j1 OI XRAN-MrlAL 10 r This tegbijqlrepot &W, b###4 'wiM &Od is 6111rov~ for puie"I" n nM.2 (7b). The UTIAS 10 cm x 18 cm Hypervelocity Shock.-Tube has) been used in recent years to study ionizing shock structures, flat-plate and side-wall boundary layers and nonstationary oblique shock-wave diffractions over compression corners. These phenomena were recorded using a 23-cm dia field of view Mach-Zehnder interferometer equipped with a giant-pulse dual-frequency ruby laser.In order to extract the maximum amount of data in these complex flows a digital evaluation method was employed. For this technique a new approach to the theory of interference was developed. In this approach the spatial coordinates (x,y) of the various lines of interference (fringes) on the interferograms are put into digital form, thereby making a computer analysis possible.

An Experimental Study of Nonstationary Instabilities of Planar Shock Waves in Ionizing Argon

“…Stting t = 900 us gives the largest giant pulse with insignificant normal lasing; this is the setting used to take interferograms at this facility, in order to get one set of bright fringes with no "ghost" fringes (Ref. 19). For this study it was found that operating the Q-switch at an intermediate value of t produced a moderate-strangth giant pulse and several very-shortduration ngrmal-lasing pulses of usable energy.…”

“…Up-dated alignment procedures are given in Ref. 19. A short description of the optical components involved will facilitate a discussion of the application of interferometry to the present study.…”