scholarly journals Redistribution of energy in a viscous heat-conductive medium during the interaction of a shock wave with a temperature layered plasma region

2020 ◽  
Vol 1698 ◽  
pp. 012004
Author(s):  
O A Azarova ◽  
K V Krasnobaev ◽  
O V Kravchenko ◽  
T A Lapushkina ◽  
A V Erofeev
2019 ◽  
Vol 54 (3) ◽  
pp. 404-413
Author(s):  
O. A. Azarova ◽  
E. M. Shakhov

Aerospace ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 326
Author(s):  
O. A. Azarova ◽  
T. A. Lapushkina ◽  
K. V. Krasnobaev ◽  
O. V. Kravchenko

The paper is devoted to the problem of the interaction between a shock wave and a thermally stratified energy source for the purpose of supersonic/hypersonic flow control realization. The effect of the thermally stratified energy source on a shock wave with the Mach number in the range of 6–12 is researched numerically based on the Navier-Stokes system of equations. Redistribution of specific internal energy and volume density of kinetic energy behind the wave front is investigated. Multiple manifestations of the Richtmyer-Meshkov instability has been obtained which has caused the blurring and disappearance of shock wave and contact discontinuity fronts in density fields. A study of the efficiency of using a stratified energy source instead of a homogeneous one with the same value of the full energy is carried out. The agreement with the available experimental data for the shock wave Mach number 6 has been obtained.


Author(s):  
А.Ю. Кузнецов ◽  
И.В. Мурсенкова ◽  
П.Ю. Уланов

The spatio-temporal distribution of the radiation of the surface sliding discharge with a duration of ~ 300 ns in stationary air at pressures of 2–200 Torr and under the interaction with plane shock waves at Mach numbers 2.8-3.3 was experimentally studied. The dynamics of the discharge radiation based on the processing of streak images and 9-frame images of the glow, the spectra of the radiation, and the discharge current are analyzed. It is shown that the dependence of the radiation intensity of the discharge interacting with the shock wave correlates with the simulated time dependence of the population of the C3Πu state of nitrogen under shock compression of the plasma region.


Author(s):  
R. Sharma ◽  
B.L. Ramakrishna ◽  
N.N. Thadhani ◽  
D. Hianes ◽  
Z. Iqbal

After materials with superconducting temperatures higher than liquid nitrogen have been prepared, more emphasis has been on increasing the current densities (Jc) of high Tc superconductors than finding new materials with higher transition temperatures. Different processing techniques i.e thin films, shock wave processing, neutron radiation etc. have been applied in order to increase Jc. Microstructural studies of compounds thus prepared have shown either a decrease in gram boundaries that act as weak-links or increase in defect structure that act as flux-pinning centers. We have studied shock wave synthesized Tl-Ba-Cu-O and shock wave processed Y-123 superconductors with somewhat different properties compared to those prepared by solid-state reaction. Here we report the defect structures observed in the shock-processed Y-124 superconductors.


Author(s):  
M.A. Mogilevsky ◽  
L.S. Bushnev

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.


Author(s):  
Kenneth S. Vecchio

Shock-induced reactions (or shock synthesis) have been studied since the 1960’s but are still poorly understood, partly due to the fact that the reaction kinetics are very fast making experimental analysis of the reaction difficult. Shock synthesis is closely related to combustion synthesis, and occurs in the same systems that undergo exothermic gasless combustion reactions. The thermite reaction (Fe2O3 + 2Al -> 2Fe + Al2O3) is prototypical of this class of reactions. The effects of shock-wave passage through porous (powder) materials are complex, because intense and non-uniform plastic deformation is coupled with the shock-wave effects. Thus, the particle interiors experience primarily the effects of shock waves, while the surfaces undergo intense plastic deformation which can often result in interfacial melting. Shock synthesis of compounds from powders is triggered by the extraordinarily high energy deposition rate at the surfaces of the powders, forcing them in close contact, activating them by introducing defects, and heating them close to or even above their melting temperatures.


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