Shock velocity in weakly ionized nitrogen, air, and argon
- Air Force Research Laboratory, Wright Patterson, Ohio 45433 (United States)
The goal of this research was to determine the principal mechanism(s) for the shock velocity increase in weakly ionized gases. This paper reports experimental data on the propagation of spark-generated shock waves (1<Mach<3) into weakly ionized nitrogen, air, and argon glow discharges (1 <p<20 Torr). In order to distinguish between effects due solely to the presence of electrons and effects due to heating of the background gas via elastic collisions with electrons, the weakly ionized discharge was pulsed on/off. Laser deflection methods determined the shock velocity, and the electron number density was collected using a microwave hairpin resonator. In the afterglow of nitrogen, air, and argon discharges, the shock velocity first decreased, not at the characteristic time for electrons to diffuse to the walls, but rather at the characteristic time for the centerline gas temperature to equilibrate with the wall temperature. These data support the conclusion that the principal mechanism for the increase in shock velocity in weakly ionized gases is thermal heating of the neutral gas species via elastic collisions with electrons.
- OSTI ID:
- 20991245
- Journal Information:
- Physics of Fluids (1994), Journal Name: Physics of Fluids (1994) Journal Issue: 3 Vol. 19; ISSN 1070-6631; ISSN PHFLE6
- Country of Publication:
- United States
- Language:
- English
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