Studies on the Hypersonic Flow Using a Double-Diaphragm Shock Tube

Abstract

A shock tube having two partition diaphragms is devised for generating a hypersonic flow free from air-liquefaction. The tube consists of a high and a medium pressure chambers of equal cross-section and a low pressure chamber with a narrow, slit-shaped inlet and a large area divergence. Hypersonic flow is generated by the expansion into the low pressure chamber of the air, which is initially contained in the medium pressure chamber and compressed to high pressure and temperature by the nearly clossed-wall reflection of the shock wave created by the rupture of the diaphragm between high and medium pressure chambers.
Flow of Mach number 6.4 with a duration of 1 millisecond is obtained and used for the studies of the flow past elliptic-nosed plates. Axisratios tested are 8, 1 (semi-circular nose) and 0 (square nose). Pressure distribution over the surface and head drag coefficient are determined by using a Mach-Zehnder interferometer.