Structure of relaxation zones behind a shock front in chemically active gas mixtures

A. L. Ni; O. S. Ryzhov

doi:10.1007/bf00910135

Molecular velocity distribution in a shock front in gas mixtures

Fluid Dynamics ◽

10.1007/bf01058982 ◽

1990 ◽

Vol 25 (2) ◽

pp. 286-292

Author(s):

A. P. Genich ◽

S. V. Kulikov ◽

G. B. Manelis ◽

S. L. Chereshnev

Keyword(s):

Velocity Distribution ◽

Shock Front ◽

Gas Mixtures ◽

Molecular Velocity

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Dalton’s and Amagat’s laws fail in gas mixtures with shock propagation

Science Advances ◽

10.1126/sciadv.aax4749 ◽

2019 ◽

Vol 5 (12) ◽

pp. eaax4749

Author(s):

P. Wayne ◽

S. Cooper ◽

D. Simons ◽

I. Trueba-Monje ◽

D. Freelong ◽

...

Keyword(s):

Shock Front ◽

Sulfur Hexafluoride ◽

Theoretical Work ◽

Gas Mixtures ◽

Shock Propagation ◽

Kinetic Molecular Theory ◽

Partial Pressures ◽

Partial Volumes ◽

Post Shock ◽

Temperature And Pressure

A shock propagating through a gas mixture leads to pressure, temperature, and density increases across the shock front. Rankine-Hugoniot relations correlating pre- and post-shock quantities describe a calorically perfect gas but deliver a good approximation for real gases, provided the pre-shock conditions are well characterized with a thermodynamic mixing model. Two classic thermodynamic models of gas mixtures are Dalton’s law of partial pressures and Amagat’s law of partial volumes. We measure post-shock temperature and pressure in experiments with nonreacting binary mixtures of sulfur hexafluoride and helium (two dramatically disparate gases) and show that neither model can accurately predict the observed values, on time scales much longer than that of the shock front passage, due to the models’ implicit assumptions about mixture behavior on the molecular level. However, kinetic molecular theory can help account for the discrepancy. Our results provide starting points for future theoretical work, experiments, and code validation.

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Investigation of shock-wave deformation history from recovered structure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143754 ◽

1986 ◽

Vol 44 ◽

pp. 434-435

Author(s):

M.A. Mogilevsky ◽

L.S. Bushnev

Keyword(s):

Shock Wave ◽

Plastic Deformation ◽

Dislocation Density ◽

Shock Waves ◽

Shock Front ◽

Single Crystals ◽

Residual Deformation ◽

Deformation Structure ◽

Deformation History ◽

Deformation Velocity

Single crystals of Al were loaded by 15 to 40 GPa shock waves at 77 K with a pulse duration of 1.0 to 0.5 μs and a residual deformation of ∼1%. The analysis of deformation structure peculiarities allows the deformation history to be re-established.After a 20 to 40 GPa loading the dislocation density in the recovered samples was about 1010 cm-2. By measuring the thickness of the 40 GPa shock front in Al, a plastic deformation velocity of 1.07 x 108 s-1 is obtained, from where the moving dislocation density at the front is 7 x 1010 cm-2. A very small part of dislocations moves during the whole time of compression, i.e. a total dislocation density at the front must be in excess of this value by one or two orders. Consequently, due to extremely high stresses, at the front there exists a very unstable structure which is rearranged later with a noticeable decrease in dislocation density.

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