High-speed shock-wave investigation in rarefied gas

Abstract

High-speed shock-wave propagation in a cylindrical tube at low initial gas pressure has been investigated. A shock-wave was excited by fast magnetic compression of a plasma in a conical θ-pinch-type electrodeless device. The Mach number varied from 10 to 100, and the initial pressure from 20 μm Hg to 250 μm Hg. At high initial pressures the shock-wave properties were identical to those of a ‘snow-plough’ model. At low pressures an anomalous wave attenuation was observed which could not be explained by the existing theory. The shock-front width is in good agreement with that predicted by the ion-ion collision theory.

Physics of meteor generated shock waves in the Earth’s atmosphere – A review

“…In a strict sense however, the transition from the vapor cloud to the shock front takes place when the magnitude of the jump in pressure, density and temperature inside of the hydrodynamic shielding is large relative to the ambient air, thereby creating a discontinuity in those parameters at the shock front (Boyd et al, 1995). At this point, a rapid translational and radial expansion of the high temperature flow field behind the shock envelope around the meteoroid can be treated as a hydrodynamic flow in a vacuum (e.g., Kornegay, 1965;Masoud et al, 1969;Kustova et al, 2011). Consequently, the flow within the meteor flow field (which is encompassed by the shock envelope) can be appropriately described by the Navier-Stokes equations for compressible flow (Hayes and Probstein, 1959).…”

“…A simple way to conceptualize a meteor shock wave is to think of it in terms of a snow plough analogy (Bershader, 1960;Masoud et al, 1969). The gas dynamics analogy to a meteor generated shock wave is the shock wave generated by a hypersonic blunt body.…”

“…As mentioned earlier in this section, a simple way to conceptualize a meteor shock wave is in terms of a snow plough analogy (Bershader, 1960;Masoud et al, 1969). Another way to visualize a meteor shock wave is to think of a meteor flow field, driven radially by a hypersonically expanding piston (e.g., see discussion in Lin, 1954;Bennett, 1958;Sakurai, 1964;Jones et al, 1968;Anderson, 2006).…”

Discontinuity of Plasma Flow Parameters

“…It has been found that for a plasma of high density [6] classical ion-ion collisions take place and a rapid collisional ionization occurs and a high luminosity is observed. the calculated mean free path [7] and the measurement of velocity damping rate of the shock front showed that for a dense back ground plasma p is varied between 0.5 and 1 and ion-ion collisions were the dominant interaction. The damping rate of the plasma shell is greater than 1 (p = 2 ) and is expected due to the divergence of the plasma shell and its interaction with the back ground rest gas.…”