The effects that changes in the diaphragm aperture have on the resulting shock tube flow

Abstract

International audienceIn a conventional shock tube, the driver and the driven sections have similar (if not identical) cross-sectional area and the diaphragm opened area, upon rupturing, is practically equal to the tube cross-sectional area. Such geometry results in generating a well-formed shock wave in the tube's driven section. The present experimental work checks the effects that changes in the diaphragm ruptured area have on the generated shock and rarefaction waves. Experiments were conducted in an 80 mm by 80 mm cross section shock tube generating incident shock waves having Mach numbers within the range from 1.06 to 1.25. In each run, pressure histories were recorded along the driven and the driver sections of the shock tube. The recorded pressures reveal that progressive reduction in the diaphragm open space resulted in a weaker shock and both longer time and distance until the compression waves generated close to the diaphragm coalesces into a shock wave. In addition, reducing the open space of the diaphragm resulted in a significant slow down in the high pressure reduction prevailing in the driver section

Diaphragm opening effects on shock wave formation and acceleration in a rectangular cross section channel

“…As the slit height increases, the normalized terminal shock velocity also increases. These observations are consistent with the conclusions made by Gaetani et al [17] and Houas et al [16] for partially opened diaphragm tests. In all of the cases, except for H F = 12, the terminal velocity in the experiments is lower than the predictions given by the theoretical model and from the simulations.…”

“…Recently, Houas et al [16] investigated the effect of diaphragm opening areas on shock wave propagation. A shock tube with a square cross section (80×80 mm 2 ) was used.…”

Finite element modelling of metallic diaphragm rupture in hypersonic shock tube

“…The net result of this process is the weakening of shock intensity and an increase in shock formation distance. Houas et al [23] studied the effect of the ratio between ruptured area and shock tube area and found similar results to Gaetani et al [13]. They found that as this area ratio decreased, the shock formation distance increased, whilst the pressure ratio across the shock decreased.…”