Gas compression and jet formation in cavities collapsed by a shock wave

Nature ◽  
1988 ◽  
Vol 332 (6164) ◽  
pp. 505-508 ◽  
Author(s):  
J. P. Dear ◽  
J. E. Field ◽  
A. J. Walton
Keyword(s):  
Shock Wave ◽  
Jet Formation ◽  
Gas Compression

Two-Dimensional Experiment on the Jet Formation during Dispersal of Solid Particles by Shock Wave

2015 ◽  
pp. 1493-1498
Author(s):  
V. Rodriguez ◽  
G. Jourdan ◽  
C. Mariani ◽  
R. Saurel ◽  
J. -C. Loraud ◽  
...  
Keyword(s):  
Shock Wave ◽  
Solid Particles ◽  
Two Dimensional ◽  
Jet Formation

scholarly journals Numerical simulation of particle jet formation induced by shock wave acceleration in a Hele-Shaw cell

Shock Waves ◽  
2017 ◽  
Vol 28 (3) ◽  
pp. 451-461 ◽  
Author(s):  
A. N. Osnes ◽  
M. Vartdal ◽  
B. A. Pettersson Reif
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Jet Formation ◽  
Hele Shaw Cell

Solid-particle jet formation under shock-wave acceleration

2013 ◽  
Vol 88 (6) ◽  
Author(s):  
V. Rodriguez ◽  
R. Saurel ◽  
G. Jourdan ◽  
L. Houas
Keyword(s):  
Shock Wave ◽  
Solid Particle ◽  
Jet Formation

Modeling of water‐gun signatures

Geophysics ◽  
1993 ◽  
Vol 58 (1) ◽  
pp. 101-109 ◽  
Author(s):  
Martin Landrø ◽  
Gitta Zaalberg‐Metselaar ◽  
Brynjulf Owren ◽  
Svein Vaage
Keyword(s):  
Shock Wave ◽  
Hydrostatic Pressure ◽  
Pressure Drop ◽  
Near Field ◽  
Water Jet ◽  
Adiabatic Expansion ◽  
Jet Formation ◽  
Water Jets ◽  
Air Chamber ◽  
Main Effect

A method for calculating the acoustic signal generated by a water gun is presented. The equations describing the shuttle motion and the water jet formation are derived with the assumption that the water is incompressible. The motion of the shuttle is evaluated by assuming adiabatic expansion of the air initially contained in the air chamber of the gun. The formation and dynamics of the water jets emerging from the gun ports are closely connected to the shuttle motion. The combined effect of the water motion through the gun ports and the collapse of a cavity inside the gun nozzle can explain the first part of a water‐gun signature, often referred to as the precursor. The last part of the signature is mainly an impulsive shock wave caused by the collapse of external cavities. It is assumed that the external cavities are formed due to the pressure drop behind each water jet, and that the cavities collapse due to the hydrostatic pressure. The main effect of including interaction between the external cavities is to increase the bubble period (i.e., the collapse time). Comparison between modeled and measured near‐field signatures for an S80 SODERA water gun show a difference of less than 5 percent of the energy in the measurement.

A new type of defect structure in 124-superconducting oxide revealed by HREM

1991 ◽  
Vol 49 ◽  
pp. 1092-1093
Author(s):  
R. Sharma ◽  
B.L. Ramakrishna ◽  
N.N. Thadhani ◽  
D. Hianes ◽  
Z. Iqbal
Keyword(s):  
Shock Wave ◽  
Defect Structure ◽  
Neutron Radiation ◽  
Weak Links ◽  
Defect Structures ◽  
New Materials ◽  
New Type ◽  
Current Densities ◽  
Processing Techniques ◽  
Microstructural Studies

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.

Investigation of shock-wave deformation history from recovered structure

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.

Electron microscopy study of shock synthesis of silicides

1993 ◽  
Vol 51 ◽  
pp. 1162-1163
Author(s):  
Kenneth S. Vecchio
Keyword(s):  
Shock Wave ◽  
Plastic Deformation ◽  
Close Contact ◽  
Microscopy Study ◽  
High Energy ◽  
Electron Microscopy Study ◽  
Powder Materials ◽  
Porous Powder ◽  
Wave Effects ◽  
Wave Passage

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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