Turbulence amplification by a shock wave and rapid distortion theory

1993 ◽  
Vol 5 (10) ◽  
pp. 2539-2550 ◽  
Author(s):  
L. Jacquin ◽  
C. Cambon ◽  
E. Blin
Keyword(s):  
Shock Wave ◽  
Rapid Distortion Theory

Rapid distortion theory analysis on the interaction between homogeneous turbulence and a planar shock wave

2016 ◽  
Vol 802 ◽  
pp. 108-146 ◽  
Author(s):  
T. Kitamura ◽  
K. Nagata ◽  
Y. Sakai ◽  
A. Sasoh ◽  
Y. Ito
Keyword(s):  
Shock Wave ◽  
Wave Interaction ◽  
Direct Consequence ◽  
Homogeneous Turbulence ◽  
Rapid Distortion Theory ◽  
Hugoniot Relation ◽  
Planar Shock ◽  
Planar Shock Wave ◽  
The One ◽  
High Wavenumbers

The interactions between homogeneous turbulence and a planar shock wave are analytically investigated using rapid distortion theory (RDT). Analytical solutions in the solenoidal modes are obtained. Qualitative answers to unsolved questions in a report by Andreopoulos et al. (Annu. Rev. Fluid Mech., vol. 524, 2000, pp. 309–345) are provided within the linear theoretical framework. The results show that the turbulence kinetic energy (TKE) is increased after interaction with a shock wave and that the contributions to the amplification can be interpreted primarily as the combined effect of shock-induced compression, which is a direct consequence of the Rankine–Hugoniot relation, and the nonlinear effect, which is an indirect consequence of the Rankine–Hugoniot relation via the perturbation manner. For initial homogeneous axisymmetric turbulence, the amplification of the TKE depends on the initial degree of anisotropy. Furthermore, the increase in energy at high wavenumbers is confirmed by the one-dimensional spectra. The enstrophy is also increased; its increase is more significant than that of the TKE because of the significant increase in enstrophy at high wavenumbers. The vorticity components perpendicular to the shock-induced compressed direction are amplified more than the parallel vorticity component. These results strongly suggest that a high resolution is needed to obtain accurate results for the turbulence–shock-wave interaction. The integral length scales ($L$) and the Taylor microscales ($\unicode[STIX]{x1D706}$) are decreased for most cases after the interaction. However, $L_{22,3}(=\,L_{33,2})$ and $\unicode[STIX]{x1D706}_{22,3}(=\,\unicode[STIX]{x1D706}_{33,2})$ are amplified. Here, the subscripts 2 and 3 indicate the perpendicular components relative to the shock-induced compressed direction. The dissipation length and TKE dissipation rate are amplified.

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.

1264: Predictors of Shock-Wave Lithotripsy Success for Proximal Ureteral Calculi on Non-Contrast CT?

2007 ◽  
Vol 177 (4S) ◽  
pp. 417-417
Author(s):  
Eric A. Singer ◽  
Jared D. Christensen ◽  
Susan Messing ◽  
Erdal Erturk
Keyword(s):  
Shock Wave ◽  
Shock Wave Lithotripsy ◽  
Ureteral Calculi ◽  
Contrast Ct

1108: Treatment Strategy Improves the in Vivo Stone Comminution Efficiency and Reduces Renal Tissue Injury During Shock Wave Lithotripsy

2005 ◽  
Vol 173 (4S) ◽  
pp. 300-301
Author(s):  
Michaella E. Maloney ◽  
Pei Zhong ◽  
Charles G. Marguet ◽  
Yufeng F. Zhou ◽  
Jeffrey C. Sung ◽  
...  
Keyword(s):  
Shock Wave ◽  
Treatment Strategy ◽  
Shock Wave Lithotripsy ◽  
Tissue Injury ◽  
Renal Tissue
Sign in / Sign up

Export Citation Format

Share Document