Details are given of an implicit six-point finite-difference scheme for solving two-temperature, laminar, boundary-layer flows not in chemical equilibrium in ionizing argon. The analysis extends previous work by considering the radiation-energy loss and the chemical reactions due to atom-atom and electron-atom collisions in the ionizing boundary-layer and free-stream flow. Also included are variations in transport properties based on known elastic-scattering cross-sections, effects of chemical reactions, radiation-energy loss and the electric-sheath wall boundary conditions. The results are compared with dual-wavelength interferometric boundary-layer data obtained by using a Mach-Zehnder interferometer 23 cm in diameter with the UTIAS 10 × 18 cm Hypervelocity Shock Tube for shocks of initial Mach numbers Ms ∼ 13 and 16 moving into argon at a pressure p0 ∼ 5 torr and temperature T0 ∼ 297 °K. Considering the difficulties involved in solving such complex plasma flows, satisfactory agreement was obtained between analytic and experimental total-density profiles and electron-number-density profiles for the case Ms ∼ 16 and good agreement for Ms ∼ 13.

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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.

A technique is described by which the flow properties in a conventional diaphragm shock tube were determined from an analysis of the particle trajectories within the flow. The particle trajectories were obtained by high-speed photography of smoke tracers placed at 10 cm intervals along the 8 m length of the tube. The subsequent analysis gave the space and time variation of pressure, density, velocity, and temperature of the gas throughout the tube, for a shock of intermediate strength. The results are compared with those made using other measurement devices for pressure and density and it is concluded that the technique gives the flow properties to an accuracy of about 5%. The technique also revealed some aberrations of the flow which had not been detected by other means.