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Sample records for compressive shock wave

  1. Shock-wave studies of anomalous compressibility of glassy carbon

    SciTech Connect

    Molodets, A. M. Golyshev, A. A.; Savinykh, A. S.; Kim, V. V.

    2016-02-15

    The physico-mechanical properties of amorphous glassy carbon are investigated under shock compression up to 10 GPa. Experiments are carried out on the continuous recording of the mass velocity of compression pulses propagating in glassy carbon samples with initial densities of 1.502(5) g/cm{sup 3} and 1.55(2) g/cm{sup 3}. It is shown that, in both cases, a compression wave in glassy carbon contains a leading precursor with amplitude of 0.135(5) GPa. It is established that, in the range of pressures up to 2 GPa, a shock discontinuity in glassy carbon is transformed into a broadened compression wave, and shock waves are formed in the release wave, which generally means the anomalous compressibility of the material in both the compression and release waves. It is shown that, at pressure higher than 3 GPa, anomalous behavior turns into normal behavior, accompanied by the formation of a shock compression wave. In the investigated area of pressure, possible structural changes in glassy carbon under shock compression have a reversible character. A physico-mechanical model of glassy carbon is proposed that involves the equation of state and a constitutive relation for Poisson’s ratio and allows the numerical simulation of physico-mechanical and thermophysical properties of glassy carbon of different densities in the region of its anomalous compressibility.

  2. Failure waves in shock-compressed glasses

    NASA Astrophysics Data System (ADS)

    Kanel, Gennady I.

    2005-07-01

    The failure wave is a network of cracks that are nucleated on the surface and propagate into the elastically stressed body. It is a mode of catastrophic fracture in an elastically stressed media whose relevance is not limited to impact events. In the presentation, main properties of the failure waves are summarized and discussed. It has been shown that the failure wave is really a wave process which is characterized by small increase of the longitudinal stress and corresponding increments of the particle velocity and the density. The propagation velocity of the failure wave is less than the sound speed; it is not directly related to the compressibility but is determined by the crack growth speed. Transformation of elastic compression wave followed by the failure wave in a thick glass plate into typical two-wave configuration in a pile of thin glass plates confirms crucial role of the surfaces. The latter, as well as specific kinematics of the process distinguishes the failure wave from a time-dependent inelastic compressive behavior of brittle materials. The failure wave is steady if the stress state ahead of it is supported unchanging. Mechanism of this self-supporting propagation of compressive fracture is not quite clear as yet. On the other hand, collected data about its kinematics allow formulating phenomenological models of the phenomenon. In some sense the process is similar to the diffusion of cracks from a source on the glass surface. However, the diffusion-like models contradict to observed steady propagation of the failure wave. Analogy with a subsonic combustion wave looks more fruitful. Computer simulations based on the phenomenological combustion-like model reproduces well all kinematical aspects of the phenomenon.

  3. Intense shock waves and shock-compressed gas flows in the channels of rail accelerators

    NASA Astrophysics Data System (ADS)

    Bobashev, S. V.; Zhukov, B. G.; Kurakin, R. O.; Ponyaev, S. A.; Reznikov, B. I.; Tverdokhlebov, K. V.

    2015-01-01

    Shock wave generation and shock-compressed gas flows attendant on the acceleration of an striker-free plasma piston in the channels of electromagnetic rail accelerators (railguns) are studied. Experiments are carried out in channels filled with helium or argon to an initial pressure of 25-500 Torr. At a pressure of 25 Torr, Mach numbers equal 32 in argon and 16 in helium. It is found that with the initial currents and gas initial densities in the channels being the same, the shock wave velocities in both gases almost coincide. Unlike standard shock tubes, a high electric field (up to 300 V/cm) present in the channel governs the motion of a shock-compressed layer. Once the charged particle concentration behind the shock wave becomes sufficiently high, the field causes part of the discharge current to pass through the shock-compressed layer. As a result, the glow of the layer becomes much more intense.

  4. Energetic Particle Transport in Strong Compressive Wave Turbulence Near Shocks

    SciTech Connect

    Le Roux, J.A.; Zank, G.P.; Li, G.; Webb, G.M.

    2005-08-01

    Strong interplanetary coronal mass ejection driven shocks are often accompanied by high levels of low frequency compressive wave turbulence. This might require a non-linear kinetic theory approach to properly describe energetic particle transport in their vicinity. We present a non-linear diffusive kinetic theory for suprathermal particle transport and stochastic acceleration along the background magnetic field in strong compressive dynamic wave turbulence to which small-scale Alfven waves are coupled. Our theory shows that the standard cosmic-ray transport equation must be revised for low suprathermal particle energies to accommodate fundamental changes in spatial diffusion (standard diffusion becomes turbulent diffusion) as well as modifications to particle convection, and adiabatic energy changes. In addition, a momentum diffusion term, which generates accelerated suprathermal particle spectra with a hard power law, must be added. Such effective first stage acceleration possibly leads to efficient injection of particles into second stage diffusive shock acceleration as described by standard theory.

  5. A study on compressive shock wave propagation in metallic foams

    NASA Astrophysics Data System (ADS)

    Wang, Zhihua; Zhang, Yifen; Ren, Huilan; Zhao, Longmao

    2010-02-01

    Metallic foam can dissipate a large amount of energy due to its relatively long stress plateau, which makes it widely applicable in the design of structural crashworthiness. However, in some experimental studies, stress enhancement has been observed when the specimens are subjected to intense impact loads, leading to severe damage to the objects being protected. This paper studies this phenomenon on a 2D mass-spring-bar model. With the model, a constitutive relationship of metal foam and corresponding loading and unloading criteria are presented; a nonlinear kinematics equilibrium equation is derived, where an explicit integration algorithm is used to calculate the characteristic of the compressive shock wave propagation within the metallic foam; the effect of heterogeneous distribution of foam microstructures on the shock wave features is also included. The results reveal that under low impact pulses, considerable energy is dissipated during the progressive collapse of foam cells, which then reduces the crush of objects. When the pulse is sufficiently high, on the other hand, stress enhancement may take place, especially in the heterogeneous foams, where high peak stresses usually occur. The characteristics of compressive shock wave propagation in the foam and the magnitude and location of the peak stress produced are strongly dependent on the mechanical properties of the foam material, amplitude and period of the pulse, as well as the homogeneity of the microstructures. This research provides valuable insight into the reliability of the metallic foams used as a protective structure.

  6. Interaction of air shock waves and porous compressible materials

    NASA Astrophysics Data System (ADS)

    Gvozdeva, L. G.; Faresov, Yu. M.; Fokeyev, V. P.

    1986-05-01

    Interaction of air shock waves and porous compressible materials was studied in an experiment with two foam-plastic materials: PPU-3M-1 polyurethane (density 33 kg/cu m) and much more rigid PKhV-1 polyvinyl chloride (density 50 kg/cu m). Tests were performed in a shock tube with 0.1x0.1 m square cross-section, a single diaphragm separating its 8 m long low-pressure segment with inspection zone and 1.5 m long high-pressure segment. The instrumentation included an array of piezoelectric pressure transducers and a digital frequency meter for velocity measurements, a Tectronix 451A oscillograph, and IAB-451 shadowgraph, and a ZhFR camera with slit scanning. Air was used as compressing gas, its initial pressure being varied from 10(3) Pa to 10(5) Pa, helium and nitrogen were used as propelling gas. The impact velocity of shock waves was varied over the N(M) = 2-5 range of the Mach number. The maximum amplitude of the pressure pulse increased as the thickness of the foam layer was increased up to 80 mm and then remained constant with further increases of that thickness, at a level depending on the material and on the intitial conditions. A maximum pressure rise by a factor of approximately 10 was attained, with 1.3 x 10(3) Pa initial pressure and an impact velocity N(M) = 5. Reducing the initial pressure to below (0.1-0.3) x 10(3) Pa, with the impact velocity maintained at N(M) = 5, reduced the pressure rise to a factor below 3. The results are interpreted taking into account elasticity forces in the solid skeleton phase and gas filtration through the pores.

  7. Experimental Results on Shock-Wave Interaction on Compression Ramps

    NASA Astrophysics Data System (ADS)

    Passaro, A.; Fantoni, G.; Biagioni, L.; Cardone, G.

    2005-02-01

    A set of new experimental tests was carried out with intrusive and non-intrusive measurements related to Shock-Wave Boundary-Layer Interaction (SWBLI) on a 15 deg compression ramp model in a Mach 6 flow with total enthalpy of 1.8-2.5 MJ/kg. The facility was the modified High Enthalpy Arc-heated Tunnel at Alta, Pisa, Italy, with improved performance and diagnostics, in order to provide good control on the actual properties of the tunnel flow. The model shape and test conditions were the same of the previous test campaign carried out during the FESTIP programme. The new results confirmed a good agreement between intrusive and non-intrusive measurements and were also compared with success with numerical predictions, eventually explaining the discrepancy on wall heat flux that was found on the previous test campaign.

  8. Compressibility and shock wave interaction effects on free shear layers

    NASA Technical Reports Server (NTRS)

    Samimy, M.; Erwin, D. E.; Elliott, G. S.

    1989-01-01

    Two compressible free shear layers with convective Mach numbers of .51 and .86 were studied as baseline configurations to investigate the effects of compressibility on the turbulence characteristics. These shear layers were then disturbed by the placement of an obstruction in the shear layer in an attempt to enhance the shear layer growth rate. These models produced a curved shock in the supersonic side of the shear layer. The results indicate a significant reduction in turbulence levels with increased compressibility. However, there are not any significant changes due to the bow shock interaction with the shear layer.

  9. Intense Shock Waves and Nonideal Plasma Physics: Shock Compression Science Award Lecture

    SciTech Connect

    Fortov, V. E.

    2006-07-28

    The physical properties of hot dense plasmas at megabar pressures in a broad area of material phase diagrams are of great interest for astro and planetary physics, and for many applications in inertial confinement fusion, energetics, defense and many other areas. The use of intense shock waves in physical and chemical research has made the exotic extreme state of plasmas an object of laboratory or semilaboratory experiments. In this presentation a brief summary of scientific results of experimental investigations of strongly coupled nonideal plasma by intense shock waves is presented. Equations of state, compositions, and thermodynamic transport properties, as well as the electrical conductivity of strongly coupled plasmas generated by intense shock and rarefaction waves, are presented. Experimental methods for the generation of high energy densities in condensed matter, drivers for shock waves, and fast diagnostics are discussed. The pressure ionization and 'dielectrization' of hot coupled matter are studied. The electrical conductivity and adiabatic compressibility of strongly coupled hydrogen and deuterium plasma demonstrate the first signature of plasma phase transition.

  10. Undergraduate Studies on Compressible Flows and Shock Waves

    NASA Astrophysics Data System (ADS)

    Stein, Keith; Schommer, Jennifer; Heppner, Benjamin

    2012-02-01

    The Bethel University physics department believes advanced lab projects and undergraduate research experiences are crucial in the development of our students, particularly those that pursue graduate studies in physics, engineering and other applied fields. Open-ended advanced lab projects are key components in several upper level physics courses. Student project work in a specific course is often enhanced by student experiences in other upper level physics courses or other research experiences. For example, projects in Fluid Mechanics (PHY420) are often enriched by experiences that students bring from projects in Optics (PHY330) and Computer Methods in Physics (PHY350). We present examples from recent undergraduate projects on compressible flows and shock waves. Special attention is given to a project involving the design, construction, and initial testing of a small supersonic blowdown tunnel. This facility was initially constructed as part of a project in Fluid Mechanics (fall 2010). Subsequent student research projects have included high-speed video shadowgraph imaging (summer 2011) and the development of a MATLAB GUI to allow for side-by-side comparisons between simulation and ongoing experiments with the tunnel (fall 2011).

  11. Shock wave compression and metallization of simple molecules

    SciTech Connect

    Ross, M.; Radousky, H.B.

    1988-03-01

    In this paper we combine shock wave studies and metallization of simple molecules in a single overview. The unifying features are provided by the high shock temperatures which lead to a metallic-like state in the rare gases and to dissociation of diatomic molecules. In the case of the rare gases, electronic excitation into the conduction band leads to a metallic-like inert gas state at lower than metallic densities and provides information regarding the closing of the band gap. Diatomic dissociation caused by thermal excitation also leads to a final metallic-like or monatomic state. Ina ddition, shock wave data can provide information concerning the short range intermolecular force of the insulator that can be useful for calculating the metallic phase transition as for example in the case of hydrogen. 69 refs., 36 figs., 2 tabs.

  12. Shock-Wave Compression and Joule-Thomson Expansion

    NASA Astrophysics Data System (ADS)

    Hoover, Wm. G.; Hoover, Carol G.; Travis, Karl P.

    2014-04-01

    Structurally stable atomistic one-dimensional shock waves have long been simulated by injecting fresh cool particles and extracting old hot particles at opposite ends of a simulation box. The resulting shock profiles demonstrate tensor temperature, Txx≠Tyy and Maxwell's delayed response, with stress lagging strain rate and heat flux lagging temperature gradient. Here this same geometry, supplemented by a short-ranged external "plug" field, is used to simulate steady Joule-Kelvin throttling flow of hot dense fluid through a porous plug, producing a dilute and cooler product fluid.

  13. Shock-wave compression and Joule-Thomson expansion.

    PubMed

    Hoover, Wm G; Hoover, Carol G; Travis, Karl P

    2014-04-11

    Structurally stable atomistic one-dimensional shock waves have long been simulated by injecting fresh cool particles and extracting old hot particles at opposite ends of a simulation box. The resulting shock profiles demonstrate tensor temperature, Txx≠Tyy and Maxwell's delayed response, with stress lagging strain rate and heat flux lagging temperature gradient. Here this same geometry, supplemented by a short-ranged external "plug" field, is used to simulate steady Joule-Kelvin throttling flow of hot dense fluid through a porous plug, producing a dilute and cooler product fluid.

  14. Shock wave compression of a large class of dual-phase liquid-vapor systems

    NASA Astrophysics Data System (ADS)

    Kuznetsov, N. M.; Timofeev, E. I.

    1986-02-01

    The shock wave compressibility of systems based on Freon 12 and 13 is investigated thermodynamically. In particular, the effect of the direction of mass transfer (evaporation or condensation) on the behavior of the shock adiabats of the dual-phase system is determined, and the effect of the initial state of the system and of the shock wave pressure on the shock adiabats in the liquid phase and dry vapor regions is analyzed. A method is also presented for determining the specific volumes of the system for the case of liquid evaporation under weak isentropic compression. It is shown that the curves of the shock wave velocity vs the volume vapor concentration have inflection points in the case of a fixed pressure gradient in the wave.

  15. Shock formation and the ideal shape of ramp compression waves

    SciTech Connect

    Swift, D C; Kraus, R G; Loomis, E; Hicks, D G; McNaney, J M; Johnson, R P

    2008-05-29

    We derive expressions for shock formation based on the local curvature of the flow characteristics during dynamic compression. Given a specific ramp adiabat, calculated for instance from the equation of state for a substance, the ideal nonlinear shape for an applied ramp loading history can be determined. We discuss the region affected by lateral release, which can be presented in compact form for the ideal loading history. Example calculations are given for representative metals and plastic ablators. Continuum dynamics (hydrocode) simulations were in good agreement with the algebraic forms. Example applications are presented for several classes of laser-loading experiment, identifying conditions where shocks are desired but not formed, and where long duration ramps are desired.

  16. Evolutions of elastic-plastic shock compression waves in different materials

    NASA Astrophysics Data System (ADS)

    Kanel, G. I.; Zaretsky, E. B.; Razorenov, S. V.; Savinykh, A. S.; Garkushin, G. V.

    2017-01-01

    In the paper, we discuss such unexpected features in the wave evolution in solids as a departure from self-similar development of the wave process which is accompanied with apparent sub-sonic wave propagation, changes of shape of elastic precursor wave as a result of variations in the material structure and the temperature, unexpected peculiarities of reflection of elastic-plastic waves from free surface, effects of internal friction at shock compression of glasses and some other effects.

  17. Shockless and shock wave compression of ballistic gel to 1.3 GPa

    NASA Astrophysics Data System (ADS)

    Toyoda, Y.; Gupta, Y. M.

    2014-10-01

    Plate impact experiments were conducted to determine the dynamic compression response of two ballistic gel concentrations (10 wt. % and 20 wt. %) subjected to uniaxial strain loading to 1.3 GPa. Shockless and shock wave compression of gel samples was achieved through flyer plate impacts on fused silica and z-cut quartz plates, respectively, placed ahead of the samples. Laser interferometry was used to measure the input compression wave profile and the propagated wave profile in each experiment. Using established wave analysis methods, the longitudinal stress-density compression results were obtained for each type of loading. The 20 wt. % gel showed a stiffer compression response than the 10 wt. % gel; the difference corresponded to the gel properties at ambient conditions. The shockless experiments provided both the loading paths and the peak states for this type of loading. Although the differences were small, the peak states achieved in shockless compression were below the shock wave (Hugoniot) data for both gel concentrations. The shockless compression results presented here are the first such results on gels, and provide the gel response at loading rates that are intermediate between the shock wave response and lower loading rate response. As such, they are expected to be useful for incorporating the dynamic compression response of gels in numerical simulations of impact phenomena.

  18. Constant entropy sampling and release waves of shock compressions

    NASA Astrophysics Data System (ADS)

    Maillet, Jean-Bernard; Bourasseau, Emeric; Soulard, Laurent; Clérouin, Jean; Stoltz, Gabriel

    2009-08-01

    We present or recall several equilibrium methods that allow one to compute isentropic processes, either during the compression or the release of the material. These methods are applied to compute the isentropic release of a shocked monoatomic liquid at high pressure and temperature. Moreover, equilibrium results of isentropic release are compared to the direct nonequilibrium simulation of the same process. We show that due to the viscosity of the liquid but also to nonequilibrium effects, the release of the system is not strictly isentropic.

  19. Assessment of high-resolution methods for numerical simulations of compressible turbulence with shock waves

    NASA Astrophysics Data System (ADS)

    Johnsen, Eric; Larsson, Johan; Bhagatwala, Ankit V.; Cabot, William H.; Moin, Parviz; Olson, Britton J.; Rawat, Pradeep S.; Shankar, Santhosh K.; Sjögreen, Björn; Yee, H. C.; Zhong, Xiaolin; Lele, Sanjiva K.

    2010-02-01

    Flows in which shock waves and turbulence are present and interact dynamically occur in a wide range of applications, including inertial confinement fusion, supernovae explosion, and scramjet propulsion. Accurate simulations of such problems are challenging because of the contradictory requirements of numerical methods used to simulate turbulence, which must minimize any numerical dissipation that would otherwise overwhelm the small scales, and shock-capturing schemes, which introduce numerical dissipation to stabilize the solution. The objective of the present work is to evaluate the performance of several numerical methods capable of simultaneously handling turbulence and shock waves. A comprehensive range of high-resolution methods (WENO, hybrid WENO/central difference, artificial diffusivity, adaptive characteristic-based filter, and shock fitting) and suite of test cases (Taylor-Green vortex, Shu-Osher problem, shock-vorticity/entropy wave interaction, Noh problem, compressible isotropic turbulence) relevant to problems with shocks and turbulence are considered. The results indicate that the WENO methods provide sharp shock profiles, but overwhelm the physical dissipation. The hybrid method is minimally dissipative and leads to sharp shocks and well-resolved broadband turbulence, but relies on an appropriate shock sensor. Artificial diffusivity methods in which the artificial bulk viscosity is based on the magnitude of the strain-rate tensor resolve vortical structures well but damp dilatational modes in compressible turbulence; dilatation-based artificial bulk viscosity methods significantly improve this behavior. For well-defined shocks, the shock fitting approach yields good results.

  20. Assessment of high-resolution methods for numerical simulations of compressible turbulence with shock waves

    SciTech Connect

    Johnsen, Eric Larsson, Johan Bhagatwala, Ankit V.; Cabot, William H.; Moin, Parviz; Olson, Britton J.; Rawat, Pradeep S.; Shankar, Santhosh K.; Sjoegreen, Bjoern; Yee, H.C.; Zhong Xiaolin; Lele, Sanjiva K.

    2010-02-20

    Flows in which shock waves and turbulence are present and interact dynamically occur in a wide range of applications, including inertial confinement fusion, supernovae explosion, and scramjet propulsion. Accurate simulations of such problems are challenging because of the contradictory requirements of numerical methods used to simulate turbulence, which must minimize any numerical dissipation that would otherwise overwhelm the small scales, and shock-capturing schemes, which introduce numerical dissipation to stabilize the solution. The objective of the present work is to evaluate the performance of several numerical methods capable of simultaneously handling turbulence and shock waves. A comprehensive range of high-resolution methods (WENO, hybrid WENO/central difference, artificial diffusivity, adaptive characteristic-based filter, and shock fitting) and suite of test cases (Taylor-Green vortex, Shu-Osher problem, shock-vorticity/entropy wave interaction, Noh problem, compressible isotropic turbulence) relevant to problems with shocks and turbulence are considered. The results indicate that the WENO methods provide sharp shock profiles, but overwhelm the physical dissipation. The hybrid method is minimally dissipative and leads to sharp shocks and well-resolved broadband turbulence, but relies on an appropriate shock sensor. Artificial diffusivity methods in which the artificial bulk viscosity is based on the magnitude of the strain-rate tensor resolve vortical structures well but damp dilatational modes in compressible turbulence; dilatation-based artificial bulk viscosity methods significantly improve this behavior. For well-defined shocks, the shock fitting approach yields good results.

  1. On the formation of Friedlander waves in a compressed-gas-driven shock tube

    PubMed Central

    Tasissa, Abiy F.; Hautefeuille, Martin; Fitek, John H.; Radovitzky, Raúl A.

    2016-01-01

    Compressed-gas-driven shock tubes have become popular as a laboratory-scale replacement for field blast tests. The well-known initial structure of the Riemann problem eventually evolves into a shock structure thought to resemble a Friedlander wave, although this remains to be demonstrated theoretically. In this paper, we develop a semi-analytical model to predict the key characteristics of pseudo blast waves forming in a shock tube: location where the wave first forms, peak over-pressure, decay time and impulse. The approach is based on combining the solutions of the two different types of wave interactions that arise in the shock tube after the family of rarefaction waves in the Riemann solution interacts with the closed end of the tube. The results of the analytical model are verified against numerical simulations obtained with a finite volume method. The model furnishes a rational approach to relate shock tube parameters to desired blast wave characteristics, and thus constitutes a useful tool for the design of shock tubes for blast testing. PMID:27118888

  2. On the formation of Friedlander waves in a compressed-gas-driven shock tube.

    PubMed

    Tasissa, Abiy F; Hautefeuille, Martin; Fitek, John H; Radovitzky, Raúl A

    2016-02-01

    Compressed-gas-driven shock tubes have become popular as a laboratory-scale replacement for field blast tests. The well-known initial structure of the Riemann problem eventually evolves into a shock structure thought to resemble a Friedlander wave, although this remains to be demonstrated theoretically. In this paper, we develop a semi-analytical model to predict the key characteristics of pseudo blast waves forming in a shock tube: location where the wave first forms, peak over-pressure, decay time and impulse. The approach is based on combining the solutions of the two different types of wave interactions that arise in the shock tube after the family of rarefaction waves in the Riemann solution interacts with the closed end of the tube. The results of the analytical model are verified against numerical simulations obtained with a finite volume method. The model furnishes a rational approach to relate shock tube parameters to desired blast wave characteristics, and thus constitutes a useful tool for the design of shock tubes for blast testing.

  3. Control of shock-wave boundary-layer interactions by bleed in supersonic mixed compression inlets

    NASA Technical Reports Server (NTRS)

    Fukuda, M. K.; Reshotko, E.; Hingst, W. R.

    1975-01-01

    An experimental investigation has been conducted to determine the effect of bleed region geometry and bleed rate on shock wave-boundary layer interactions in an axisymmetric, mixed-compression inlet at a Mach number of 2.5. The full realizable reduction in transformed form factor is obtained by bleeding off about half the incident boundary layer mass flow. Bleeding upstream or downstream of the shock-induced pressure rise is preferable to bleeding across the shock-induced pressure rise. Slanted holes are more effective than normal holes. Two different bleed hole sizes were tested without detectable difference in performance.

  4. Control of shock wave-boundary layer interactions by bleed in supersonic mixed compression inlets

    NASA Technical Reports Server (NTRS)

    Fukuda, M. K.; Hingst, W. G.; Reshotko, E.

    1975-01-01

    An experimental investigation was conducted to determine the effect of bleed on a shock wave-boundary layer interaction in an axisymmetric mixed-compression supersonic inlet. The inlet was designed for a free-stream Mach number of 2.50 with 60-percent supersonic internal area contraction. The experiment was conducted in the NASA Lewis Research Center 10-Foot Supersonic Wind Tunnel. The effects of bleed amount and bleed geometry on the boundary layer after a shock wave-boundary layer interaction were studied. The effect of bleed on the transformed form factor is such that the full realizable reduction is obtained by bleeding of a mass flow equal to about one-half of the incident boundary layer mass flow. More bleeding does not yield further reduction. Bleeding upstream or downstream of the shock-induced pressure rise is preferable to bleeding across the shock-induced pressure rise.

  5. Depolarization and Electrical Response of Porous PZT 95/5 Ferroelectric Ceramics under Shock Wave Compression

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Zhu; Jiang, Yi-Xuan; Zhang, Pan; Wang, Xing-Zhe; He, Hong-Liang

    2014-07-01

    The release of bound charges by shock wave loading of poled lead zirconate titanate (PZT 95/5) ferroelectric ceramics can result in a high-power electrical energy output. In this study, a theoretical formulation describing the depolarization and electrical response of porous PZT 95/5 ceramics in the normal mode to shock wave compression loading perpendicular to the polarization direction is developed. The depoling process in porous poled PZT 95/5 ceramics is analyzed by using a parallel circuit consisting of a current source, capacitance, conductance and a circuit load. This modeling takes the effects of porosity on wave velocity and remanent polarization and dielectric constant into account, and the effects of variations in dielectric constant and conductivity in the shocked region are assessed. The output current characteristics of porous PZT 95/5 ceramics under short-circuit and resistive load conditions are analyzed and compared with the experiment, with the results showing that theoretical predictions taking into consideration the porosity of ferroelectric ceramics are in close agreement with the experimentally measured electrical response of porous PZT 95/5 under shock wave compression loading.

  6. Shock-wave compression of silica gel as a model material for comets

    NASA Astrophysics Data System (ADS)

    Arasuna, Akane; Okuno, Masayuki; Chen, Liliang; Mashimo, Tsutomu; Okudera, Hiroki; Mizukami, Tomoyuki; Arai, Shoji

    2016-07-01

    A shock-wave compression experiment using synthesized silica gel was investigated as a model for a comet impact event on the Earth's surface. The sample shocked at 20.7 GPa showed considerable structural changes, a release of water molecules, and the dehydration of silanol (Si-OH) that led to the formation of a new Si-O-Si network structure containing larger rings (e.g., six-membered ring of SiO4 tetrahedra). The high aftershock temperature at 20.7 GPa, which could be close to 800 °C, influenced the sample structure. However, some silanols, which were presumed to be the mutually hydrogen-bonded silanol group, remained at pressures >20.7 GPa. This type of silanol along with a small number of water molecules may remain even after shock compression at 30.9 GPa, although the intermediate structure of the sample recovered was similar to that of silica glass.

  7. Material strength and inelastic deformation of silicon carbide under shock wave compression

    SciTech Connect

    Feng, R.; Raiser, G.F.; Gupta, Y.M.

    1998-01-01

    In-material, lateral, manganin foil gauge measurements were obtained in dense polycrystalline silicon carbide (SiC) shocked to peak longitudinal stresses ranging from 10{endash}24 GPa. The lateral gauge data were analyzed to determine the lateral stresses in the shocked SiC and the results were checked for self-consistency through dynamic two-dimensional computations. Over the stress range examined, the shocked SiC has an extremely high strength: the maximum shear stress supported by the material in the shocked state increases from 4.5 GPa at the Hugoniot elastic limit (HEL) of the material (11.5 GPa) to 7.0 GPa at stresses approximately twice the HEL. The latter value is 3.7{percent} of the shear modulus of the material. The elastic{endash}inelastic transition in the shocked SiC is nearly indistinctive. At stresses beyond twice the HEL, the data suggest a gradual softening with increasing shock compression. The post-HEL material strength evolution resembles neither catastrophic failure due to massive cracking nor classical plasticity response. Stress confinement, inherent in plane shock wave compression, contributes significantly to the observed material response. The results obtained are interpreted qualitatively in terms of an inhomogeneous deformation mechanism involving both in-grain microplasticity and highly confined microfissures. {copyright} {ital 1998 American Institute of Physics.}

  8. An Evaluation of the Compressive Properties of Helmet Pads Pre- and Post-Shock Wave Overpressure Exposure

    DTIC Science & Technology

    2015-08-14

    COMPRESSIVE PROPERTIES OF HELMET PADS PRE - AND POST- SHOCK WAVE OVERPRESSURE EXPOSURE by Marina Carboni Xiaolin Zhen Barry DeCristofano and... PRE - AND POST-SHOCK WAVE OVERPRESSURE EXPOSURE 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Marina Carboni...release; distribution is unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT This report documents a study of the compressive properties between pre - and

  9. Nonstandard Analysis and Shock Wave Jump Conditions in a One-Dimensional Compressible Gas

    NASA Technical Reports Server (NTRS)

    Baty, Roy S.; Farassat, Fereidoun; Hargreaves, John

    2007-01-01

    Nonstandard analysis is a relatively new area of mathematics in which infinitesimal numbers can be defined and manipulated rigorously like real numbers. This report presents a fairly comprehensive tutorial on nonstandard analysis for physicists and engineers with many examples applicable to generalized functions. To demonstrate the power of the subject, the problem of shock wave jump conditions is studied for a one-dimensional compressible gas. It is assumed that the shock thickness occurs on an infinitesimal interval and the jump functions in the thermodynamic and fluid dynamic parameters occur smoothly across this interval. To use conservations laws, smooth pre-distributions of the Dirac delta measure are applied whose supports are contained within the shock thickness. Furthermore, smooth pre-distributions of the Heaviside function are applied which vary from zero to one across the shock wave. It is shown that if the equations of motion are expressed in nonconservative form then the relationships between the jump functions for the flow parameters may be found unambiguously. The analysis yields the classical Rankine-Hugoniot jump conditions for an inviscid shock wave. Moreover, non-monotonic entropy jump conditions are obtained for both inviscid and viscous flows. The report shows that products of generalized functions may be defined consistently using nonstandard analysis; however, physically meaningful products of generalized functions must be determined from the physics of the problem and not the mathematical form of the governing equations.

  10. Nonstandard Analysis and Shock Wave Jump Conditions in a One-Dimensional Compressible Gas

    SciTech Connect

    Roy S. Baty, F. Farassat, John A. Hargreaves

    2007-05-25

    Nonstandard analysis is a relatively new area of mathematics in which infinitesimal numbers can be defined and manipulated rigorously like real numbers. This report presents a fairly comprehensive tutorial on nonstandard analysis for physicists and engineers with many examples applicable to generalized functions. To demonstrate the power of the subject, the problem of shock wave jump conditions is studied for a one-dimensional compressible gas. It is assumed that the shock thickness occurs on an infinitesimal interval and the jump functions in the thermodynamic and fluid dynamic parameters occur smoothly across this interval. To use conservations laws, smooth pre-distributions of the Dirac delta measure are applied whose supports are contained within the shock thickness. Furthermore, smooth pre-distributions of the Heaviside function are applied which vary from zero to one across the shock wave. It is shown that if the equations of motion are expressed in nonconservative form then the relationships between the jump functions for the flow parameters may be found unambiguously. The analysis yields the classical Rankine-Hugoniot jump conditions for an inviscid shock wave. Moreover, non-monotonic entropy jump conditions are obtained for both inviscid and viscous flows. The report shows that products of generalized functions may be defined consistently using nonstandard analysis; however, physically meaningful products of generalized functions must be determined from the physics of the problem and not the mathematical form of the governing equations.

  11. Shock compression of precompressed deuterium

    SciTech Connect

    Armstrong, M R; Crowhurst, J C; Zaug, J M; Bastea, S; Goncharov, A F; Militzer, B

    2011-07-31

    Here we report quasi-isentropic dynamic compression and thermodynamic characterization of solid, precompressed deuterium over an ultrafast time scale (< 100 ps) and a microscopic length scale (< 1 {micro}m). We further report a fast transition in shock wave compressed solid deuterium that is consistent with the ramp to shock transition, with a time scale of less than 10 ps. These results suggest that high-density dynamic compression of hydrogen may be possible on microscopic length scales.

  12. Boundaries of the ambiguity area upon reflection of compression shock waves

    NASA Astrophysics Data System (ADS)

    Bulat, P. V.; Upyrev, V. V.

    2016-01-01

    Oblique shock waves can be reflected from hard walls, the axis, or the plane of symmetry, as well as from other counterpropagating shock waves with the formation of regular and Mach shock wave configurations. The specific form of shock wave structures is determined by the parameters of the problem: Mach number and intensity of incident shock waves. On the plane of parameters, there exists an ambiguity area in which laws of conservation admit both the regular and Mach reflection of shock waves. The boundaries of this region have been determined.

  13. Shock compression of nitrobenzene

    NASA Astrophysics Data System (ADS)

    Kozu, Naoshi; Arai, Mitsuru; Tamura, Masamitsu; Fujihisa, Hiroshi; Aoki, Katsutoshi; Yoshida, Masatake; Kondo, Ken-Ichi

    1999-06-01

    The Hugoniot (4 - 30 GPa) and the isotherm (1 - 7 GPa) of nitrobenzene have been investigated by shock and static compression experiments. Nitrobenzene has the most basic structure of nitro aromatic compounds, which are widely used as energetic materials, but nitrobenzene has been considered not to explode in spite of the fact its calculated heat of detonation is similar to TNT, about 1 kcal/g. Explosive plane-wave generators and diamond anvil cell were used for shock and static compression, respectively. The obtained Hugoniot consists of two linear lines, and the kink exists around 10 GPa. The upper line agrees well with the Hugoniot of detonation products calculated by KHT code, so it is expected that nitrobenzene detonates in that area. Nitrobenzene solidifies under 1 GPa of static compression, and the isotherm of solid nitrobenzene was obtained by X-ray diffraction technique. Comparing the Hugoniot and the isotherm, nitrobenzene is in liquid phase under experimented shock condition. From the expected phase diagram, shocked nitrobenzene seems to remain metastable liquid in solid phase region on that diagram.

  14. Mechanical Properties of PZT 52/48 under Shock and Ramp Wave Compression

    NASA Astrophysics Data System (ADS)

    Wise, J. L.; Montgomery, S. T.; Jackson, D. P.; Clark, G. E.; Duckett, E. B.

    2011-06-01

    Complementary gas-gun and electromagnetic pulse experiments have yielded data regarding the dynamic mechanical behavior for poled and unpoled specimens of a PZT (52 wt% lead zirconate plus 48 wt% lead titanate) ferroelectric ceramic subjected to shock and intermediate-strain-rate ramp wave (i . e . , quasi-isentropic) loading. For each experiment, velocity interferometer (VISAR) diagnostics provided time-resolved measurements of sample response for conditions nominally involving one-dimensional (i . e . , uniaxial strain) compression and release. Wave profiles obtained during the shock experiments have been analyzed to assess the Hugoniot Elastic Limit (HEL), Hugoniot equation of state, spall strength, and high-pressure yield strength of PZT. Profiles from the ramp wave experiments have been processed to determine the locus of isentropic stress-strain states generated in PZT for deformation rates substantially lower than those associated with shock loading. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  15. Evolutions of elastic-plastic shock compression waves in different materials

    NASA Astrophysics Data System (ADS)

    Kanel, G. I.; Zaretsky, E. B.; Razorenov, S. V.; Savinykh, A. S.; Garkushin, G. V.

    2015-06-01

    Measurements of decay of the elastic precursor wave are used to determine the initial plastic strain rate as a function of the stress. Last years we performed large series of such kind experiments with metals and alloys at various temperatures, ceramics and glasses. In course of these measurements we observed several unexpected effects which have not got exhaustive explanations yet. In the presentation, we'll discuss a departure from self-similar development of the wave process which is accompanied with apparent sub-sonic wave propagation, changes of shape of elastic precursor wave as a result of variations in the material structure and the temperature, unexpected peculiarities of reflection of elastic-plastic waves from free surface, effects of internal friction at shock compression of glasses and some other effects. It seems the experimental data contain more information about kinetics of the time-dependent phenomena than we are able to get from their analysis now. Financial support from the Russian Science Foundation via Grant No 14-12-01127 is gratefully acknowledged.

  16. Simulation of systems for shock wave/compression waves damping in technological plants

    NASA Astrophysics Data System (ADS)

    Sumskoi, S. I.; Sverchkov, A. M.; Lisanov, M. V.; Egorov, A. F.

    2016-09-01

    At work of pipeline systems, flow velocity decrease can take place in the pipeline as a result of the pumps stop, the valves shutdown. As a result, compression waves appear in the pipeline systems. These waves can propagate in the pipeline system, leading to its destruction. This phenomenon is called water hammer (water hammer flow). The most dangerous situations occur when the flow is stopped quickly. Such urgent flow cutoff often takes place in an emergency situation when liquid hydrocarbons are being loaded into sea tankers. To prevent environment pollution it is necessary to stop the hydrocarbon loading urgently. The flow in this case is cut off within few seconds. To prevent an increase in pressure in a pipeline system during water hammer flow, special protective systems (pressure relief systems) are installed. The approaches to systems of protection against water hammer (pressure relief systems) modeling are described in this paper. A model of certain pressure relief system is considered. It is shown that in case of an increase in the intensity of hydrocarbons loading at a sea tanker, presence of the pressure relief system allows to organize safe mode of loading.

  17. Diffraction of a shock wave by a compression corner; regular and single Mach reflection

    NASA Technical Reports Server (NTRS)

    Vijayashankar, V. S.; Kutler, P.; Anderson, D.

    1976-01-01

    The two dimensional, time dependent Euler equations which govern the flow field resulting from the injection of a planar shock with a compression corner are solved with initial conditions that result in either regular reflection or single Mach reflection of the incident planar shock. The Euler equations which are hyperbolic are transformed to include the self similarity of the problem. A normalization procedure is employed to align the reflected shock and the Mach stem as computational boundaries to implement the shock fitting procedure. A special floating fitting scheme is developed in conjunction with the method of characteristics to fit the slip surface. The reflected shock, the Mach stem, and the slip surface are all treated as harp discontinuities, thus, resulting in a more accurate description of the inviscid flow field. The resulting numerical solutions are compared with available experimental data and existing first-order, shock-capturing numerical solutions.

  18. Non-ideal compressible-fluid effects in oblique shock waves

    NASA Astrophysics Data System (ADS)

    Gori, G.; Vimercati, D.; Guardone, A.

    2017-03-01

    The non-monotone dependence of the speed of sound along adiabatic transformations is demonstrated to result in the admissibility of non-ideal increase of the flow Mach number across oblique shock waves, for pre-shock states in close proximity of the liquid-vapour saturation curve. This non-ideal behaviour is primarily associated with a less-than-unity value of the fundamental derivative of gasdynamics and, therefore, non-ideal shock waves are expected to be observed in flows of fluids with moderate molecular complexity. The simple yet qualitatively sound van der Waals model is used to confirm the present findings and to provide exemplary non-ideal shock waves.

  19. Al 1s-2p Absorption Spectroscopy of Shock-Wave Heating and Compression in Laser-Driven Planar Foil

    SciTech Connect

    Sawada, H.; Regan, S.P.; Radha, P.B.; Epstein, R.; Li, D.; Goncharov, V.N.; Hu, S.X.; Meyerhofer, D.D.; Delettrez, J.A.; Jaanimagi, P.A.; Smalyuk, V.A.; Boehly, T.R.; Sangster, T.C.; Yaakobi, B.; Mancini, R.C.

    2009-05-19

    Time-resolved Al 1s-2p absorption spectroscopy is used to diagnose direct-drive, shock-wave heating and compression of planar targets having nearly Fermi-degenerate plasma conditions (Te ~ 10–40 eV, rho ~ 3–11 g/cm^3) on the OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. A planar plastic foil with a buried Al tracer layer was irradiated with peak intensities of 10^14–10^15 W/cm^2 and probed with the pseudocontinuum M-band emission from a point-source Sm backlighter in the range of 1.4–1.7 keV. The laser ablation process launches 10–70 Mbar shock waves into the CH/Al/CH target. The Al 1s-2p absorption spectra were analyzed using the atomic physic code PRISMSPECT to infer Te and rho in the Al layer, assuming uniform plasma conditions during shock-wave heating, and to determine when the heat front penetrated the Al layer. The drive foils were simulated with the one-dimensional hydrodynamics code LILAC using a flux-limited (f =0.06 and f =0.1) and nonlocal thermal-transport model [V. N. Goncharov et al., Phys. Plasmas 13, 012702 (2006)]. The predictions of simulated shock-wave heating and the timing of heat-front penetration are compared to the observations. The experimental results for a wide variety of laser-drive conditions and buried depths have shown that the LILAC predictions using f = 0.06 and the nonlocal model accurately model the shock-wave heating and timing of the heat-front penetration while the shock is transiting the target. The observed discrepancy between the measured and simulated shock-wave heating at late times of the drive can be explained by the reduced radiative heating due to lateral heat flow in the corona.

  20. Excitation of dayside chorus waves due to magnetic field line compression in response to interplanetary shocks

    NASA Astrophysics Data System (ADS)

    Zhou, Chen; Li, Wen; Thorne, Richard M.; Bortnik, Jacob; Ma, Qianli; An, Xin; Zhang, Xiao-jia; Angelopoulos, Vassilis; Ni, Binbin; Gu, Xudong; Fu, Song; Zhao, Zhengyu

    2015-10-01

    The excitation of magnetospheric whistler-mode chorus in response to interplanetary (IP) shocks is investigated using wave data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft. As an example, we show a typical chorus wave excitation following an IP shock event that was observed by THEMIS in the postnoon sector near the magnetopause on 3 August 2010. We then analyze characteristic changes during this event and perform a survey of similar events during the period 2008-2014 using the THEMIS and OMNI data set. Our statistical analysis demonstrates that the chorus wave excitation/intensification in response to IP shocks occurs only at high L shells (L > 8) on the dayside. We analyzed the variations of magnetic curvature following the arrival of the IP shock and found that IP shocks lead to more homogeneous background magnetic field configurations in the near-equatorial dayside magnetosphere; and therefore, the threshold of nonlinear chorus wave growth is likely to be reduced, favoring chorus wave generation. Our results provide the observational evidence to support the concept that the geomagnetic field line configuration plays a key role in the excitation of dayside chorus.

  1. A Parametric Approach to Shape Field-Relevant Blast Wave Profiles in Compressed-Gas-Driven Shock Tube

    PubMed Central

    Sundaramurthy, Aravind; Chandra, Namas

    2014-01-01

    Detonation of a high-explosive produces shock-blast wave, shrapnel, and gaseous products. While direct exposure to blast is a concern near the epicenter, shock-blast can affect subjects, even at farther distances. When a pure shock-blast wave encounters the subject, in the absence of shrapnels, fall, or gaseous products the loading is termed as primary blast loading and is the subject of this paper. The wave profile is characterized by blast overpressure, positive time duration, and impulse and called herein as shock-blast wave parameters (SWPs). These parameters in turn are uniquely determined by the strength of high explosive and the distance of the human subjects from the epicenter. The shape and magnitude of the profile determine the severity of injury to the subjects. As shown in some of our recent works (1–3), the profile not only determines the survival of the subjects (e.g., animals) but also the acute and chronic biomechanical injuries along with the following bio-chemical sequelae. It is extremely important to carefully design and operate the shock tube to produce field-relevant SWPs. Furthermore, it is vital to identify and eliminate the artifacts that are inadvertently introduced in the shock-blast profile that may affect the results. In this work, we examine the relationship between shock tube adjustable parameters (SAPs) and SWPs that can be used to control the blast profile; the results can be easily applied to many of the laboratory shock tubes. Further, replication of shock profile (magnitude and shape) can be related to field explosions and can be a standard in comparing results across different laboratories. Forty experiments are carried out by judiciously varying SAPs such as membrane thickness, breech length (66.68–1209.68 mm), measurement location, and type of driver gas (nitrogen, helium). The effects SAPs have on the resulting shock-blast profiles are shown. Also, the shock-blast profiles of a TNT explosion from ConWep software is

  2. A parametric approach to shape field-relevant blast wave profiles in compressed-gas-driven shock tube.

    PubMed

    Sundaramurthy, Aravind; Chandra, Namas

    2014-01-01

    Detonation of a high-explosive produces shock-blast wave, shrapnel, and gaseous products. While direct exposure to blast is a concern near the epicenter, shock-blast can affect subjects, even at farther distances. When a pure shock-blast wave encounters the subject, in the absence of shrapnels, fall, or gaseous products the loading is termed as primary blast loading and is the subject of this paper. The wave profile is characterized by blast overpressure, positive time duration, and impulse and called herein as shock-blast wave parameters (SWPs). These parameters in turn are uniquely determined by the strength of high explosive and the distance of the human subjects from the epicenter. The shape and magnitude of the profile determine the severity of injury to the subjects. As shown in some of our recent works (1-3), the profile not only determines the survival of the subjects (e.g., animals) but also the acute and chronic biomechanical injuries along with the following bio-chemical sequelae. It is extremely important to carefully design and operate the shock tube to produce field-relevant SWPs. Furthermore, it is vital to identify and eliminate the artifacts that are inadvertently introduced in the shock-blast profile that may affect the results. In this work, we examine the relationship between shock tube adjustable parameters (SAPs) and SWPs that can be used to control the blast profile; the results can be easily applied to many of the laboratory shock tubes. Further, replication of shock profile (magnitude and shape) can be related to field explosions and can be a standard in comparing results across different laboratories. Forty experiments are carried out by judiciously varying SAPs such as membrane thickness, breech length (66.68-1209.68 mm), measurement location, and type of driver gas (nitrogen, helium). The effects SAPs have on the resulting shock-blast profiles are shown. Also, the shock-blast profiles of a TNT explosion from ConWep software is compared

  3. Shock compression modeling of metallic single crystals: comparison of finite difference, steady wave, and analytical solutions

    SciTech Connect

    Lloyd, Jeffrey T.; Clayton, John D.; Austin, Ryan A.; McDowell, David L.

    2015-07-10

    Background: The shock response of metallic single crystals can be captured using a micro-mechanical description of the thermoelastic-viscoplastic material response; however, using a such a description within the context of traditional numerical methods may introduce a physical artifacts. Advantages and disadvantages of complex material descriptions, in particular the viscoplastic response, must be framed within approximations introduced by numerical methods. Methods: Three methods of modeling the shock response of metallic single crystals are summarized: finite difference simulations, steady wave simulations, and algebraic solutions of the Rankine-Hugoniot jump conditions. For the former two numerical techniques, a dislocation density based framework describes the rate- and temperature-dependent shear strength on each slip system. For the latter analytical technique, a simple (two-parameter) rate- and temperature-independent linear hardening description is necessarily invoked to enable simultaneous solution of the governing equations. For all models, the same nonlinear thermoelastic energy potential incorporating elastic constants of up to order 3 is applied. Results: Solutions are compared for plate impact of highly symmetric orientations (all three methods) and low symmetry orientations (numerical methods only) of aluminum single crystals shocked to 5 GPa (weak shock regime) and 25 GPa (overdriven regime). Conclusions: For weak shocks, results of the two numerical methods are very similar, regardless of crystallographic orientation. For strong shocks, artificial viscosity affects the finite difference solution, and effects of transverse waves for the lower symmetry orientations not captured by the steady wave method become important. The analytical solution, which can only be applied to highly symmetric orientations, provides reasonable accuracy with regards to prediction of most variables in the final shocked state but, by construction, does not provide insight

  4. Shock compression modeling of metallic single crystals: comparison of finite difference, steady wave, and analytical solutions

    DOE PAGES

    Lloyd, Jeffrey T.; Clayton, John D.; Austin, Ryan A.; ...

    2015-07-10

    Background: The shock response of metallic single crystals can be captured using a micro-mechanical description of the thermoelastic-viscoplastic material response; however, using a such a description within the context of traditional numerical methods may introduce a physical artifacts. Advantages and disadvantages of complex material descriptions, in particular the viscoplastic response, must be framed within approximations introduced by numerical methods. Methods: Three methods of modeling the shock response of metallic single crystals are summarized: finite difference simulations, steady wave simulations, and algebraic solutions of the Rankine-Hugoniot jump conditions. For the former two numerical techniques, a dislocation density based framework describes themore » rate- and temperature-dependent shear strength on each slip system. For the latter analytical technique, a simple (two-parameter) rate- and temperature-independent linear hardening description is necessarily invoked to enable simultaneous solution of the governing equations. For all models, the same nonlinear thermoelastic energy potential incorporating elastic constants of up to order 3 is applied. Results: Solutions are compared for plate impact of highly symmetric orientations (all three methods) and low symmetry orientations (numerical methods only) of aluminum single crystals shocked to 5 GPa (weak shock regime) and 25 GPa (overdriven regime). Conclusions: For weak shocks, results of the two numerical methods are very similar, regardless of crystallographic orientation. For strong shocks, artificial viscosity affects the finite difference solution, and effects of transverse waves for the lower symmetry orientations not captured by the steady wave method become important. The analytical solution, which can only be applied to highly symmetric orientations, provides reasonable accuracy with regards to prediction of most variables in the final shocked state but, by construction, does not provide

  5. Shock compression of liquid hydrazine

    SciTech Connect

    Garcia, B.O.; Chavez, D.J.

    1996-05-01

    Liquid hydrazine (N{sub 2}H{sub 4}) is a propellant used for aerospace propulsion and power systems. Because the propellant modules can be subject to debris impacts during their use, the shock states that can occur in the hydrazine need to be characterized to safely predict its response. Several shock compression experiments have been conducted to investigate the shock detonability of liquid hydrazine; however, the experiments{close_quote} results disagree. Therefore, in this study, we reproduced each experiment numerically to evaluate in detail the shock wave profiles generated in the liquid hydrazine. This paper presents the results of each numerical simulation and compares the results to those obtained in experiment. {copyright} {ital 1996 American Institute of Physics.}

  6. Evaluation of Aluminum Participation in the Development of Reactive Waves in Shock Compressed HMX

    SciTech Connect

    Pahl, R. J.; Trott, W. M.; Snedigar, S.; Castaneda, J. N.

    2006-07-28

    A series of gas gun tests has been performed to examine contributions to energy release from micron-sized and nanometric aluminum powder added to sieved (212-300{mu}m) HMX. In the absence of added metal, 4-mm-thick, low-density (64-68% of theoretical maximum density) pressings of the sieved HMX respond to modest shock loading by developing distinctive reactive waves that exhibit both temporal and mesoscale spatial fluctuations. Parallel tests have been performed on samples containing 10% (by mass) aluminum in two particle sizes: 2-{mu}m and 123-nm mean particle diameter, respectively. The finely dispersed aluminum initially suppresses wave growth from HMX reactions; however, after a visible induction period, the added metal drives rapid increases in the transmitted wave particle velocity. Wave profile variations as a function of the aluminum particle diameter are discussed.

  7. Evaluation of aluminum participation in the development of reactive waves in shock compressed HMX.

    SciTech Connect

    Castaneda, Jaime N.; Pahl, Robert J.; Snedigar, Shane; Trott, Wayne Merle

    2005-07-01

    A series of gas gun tests has been performed to examine contributions to energy release from micron-sized and nanometric aluminum powder added to sieved (212-300{micro}m) HMX. In the absence of added metal, 4-mm-thick, low-density (64-68% of theoretical maximum density) pressings of the sieved HMX respond to modest shock loading by developing distinctive reactive waves that exhibit both temporal and mesoscale spatial fluctuations. Parallel tests have been performed on samples containing 10% (by mass) aluminum in two particle sizes: 2-{micro}m and 123-nm mean particle diameter, respectively. The finely dispersed aluminum initially suppresses wave growth from HMX reactions; however, after a visible induction period, the added metal drives rapid increases in the transmitted wave particle velocity. Wave profile variations as a function of the aluminum particle diameter are discussed.

  8. Al 1s-2p absorption spectroscopy of shock-wave heating and compression in laser-driven planar foil

    SciTech Connect

    Sawada, H.; Regan, S. P.; Radha, P. B.; Epstein, R.; Li, D.; Goncharov, V. N.; Hu, S. X.; Meyerhofer, D. D.; Delettrez, J. A.; Jaanimagi, P. A.; Smalyuk, V. A.; Boehly, T. R.; Sangster, T. C.; Yaakobi, B.; Mancini, R. C.

    2009-05-15

    Time-resolved Al 1s-2p absorption spectroscopy is used to diagnose direct-drive, shock-wave heating and compression of planar targets having nearly Fermi-degenerate plasma conditions (T{sub e}{approx}10-40 eV, {rho}{approx}3-11 g/cm{sup 3}) on the OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. A planar plastic foil with a buried Al tracer layer was irradiated with peak intensities of 10{sup 14}-10{sup 15} W/cm{sup 2} and probed with the pseudocontinuum M-band emission from a point-source Sm backlighter in the range of 1.4-1.7 keV. The laser ablation process launches 10-70 Mbar shock waves into the CH/Al/CH target. The Al 1s-2p absorption spectra were analyzed using the atomic physic code PRISMSPECT to infer T{sub e} and {rho} in the Al layer, assuming uniform plasma conditions during shock-wave heating, and to determine when the heat front penetrated the Al layer. The drive foils were simulated with the one-dimensional hydrodynamics code LILAC using a flux-limited (f=0.06 and f=0.1) and nonlocal thermal-transport model [V. N. Goncharov et al., Phys. Plasmas 13, 012702 (2006)]. The predictions of simulated shock-wave heating and the timing of heat-front penetration are compared to the observations. The experimental results for a wide variety of laser-drive conditions and buried depths have shown that the LILAC predictions using f=0.06 and the nonlocal model accurately model the shock-wave heating and timing of the heat-front penetration while the shock is transiting the target. The observed discrepancy between the measured and simulated shock-wave heating at late times of the drive can be explained by the reduced radiative heating due to lateral heat flow in the corona.

  9. Shock compression of liquid hydrazine

    SciTech Connect

    Garcia, B.O.; Chavez, D.J.

    1995-01-01

    Liquid hydrazine (N{sub 2}H{sub 4}) is a propellant used by the Air Force and NASA for aerospace propulsion and power systems. Because the propellant modules that contain the hydrazine can be subject to debris impacts during their use, the shock states that can occur in the hydrazine need to be characterized to safely predict its response. Several shock compression experiments have been conducted in an attempt to investigate the detonability of liquid hydrazine; however, the experiments results disagree. Therefore, in this study, we reproduced each experiment numerically to evaluate in detail the shock wave profiles generated in the liquid hydrazine. This paper presents the results of each numerical simulation and compares the results to those obtained in experiment. We also present the methodology of our approach, which includes chemical kinetic experiments, chemical equilibrium calculations, and characterization of the equation of state of liquid hydrazine.

  10. Shock waves data for minerals

    NASA Technical Reports Server (NTRS)

    Ahrens, Thomas J.; Johnson, Mary L.

    1994-01-01

    Shock compression of the materials of planetary interiors yields data which upon comparison with density-pressure and density-sound velocity profiles constrain internal composition and temperature. Other important applications of shock wave data and related properties are found in the impact mechanics of terrestrial planets and solid satellites. Shock wave equation of state, shock-induced dynamic yielding and phase transitions, and shock temperature are discussed. In regions where a substantial phase change in the material does not occur, the relationship between the particle velocity, U(sub p), and the shock velocity, U(sub s), is given by U(sub s) = C(sub 0) + S U(sub p), where C(sub 0) is the shock velocity at infinitesimally small particle velocity, or the ambient pressure bulk sound velocity. Numerical values for the shock wave equation of state for minerals and related materials of the solar system are provided.

  11. On the numerical solution of two-dimensional, laminar compressible flows with imbedded shock waves.

    NASA Technical Reports Server (NTRS)

    Goodrich, W. D.; Lamb, J. P.; Bertin, J. J.

    1972-01-01

    The complete, time-dependent Navier-Stokes equations are expressed in conservation form and solved by employing an explicit finite difference numerical technique which incorporates artificial viscosity terms of the form first suggested by Rusanov for numerical stability in the vicinity of shock waves. Surface boundary conditions are developed in a consistent and unique manner through the use of a physically oriented extrapolation procedure. From numerical experimentation an extended range for the explicit stability parameter is established. Also employed is an additional convergence parameter which relates incremental spatial steps. Convergence of the transient solution to a steady state flow was obtained after 400 to 500 time steps.

  12. a Study on Fracture Behaviors of Ceramic Using Shock Compressive Wave

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Hoon; Lee, Young-Shin; Hwang, Kwon-Tae; Shim, Woo-Sung; Park, Jong-Ho; Song, Kee-Hyeuk; Yoon, Su-Jin

    An experimental investigation was carried out to evaluate the fracture pressure and behaviors of ceramic materials for a dome port cover of an air breathing engine. The experiments were performed in a shock tube, which had a working section of 70 mm in diameter and a total length of 6 m in the shock tube. The response pressure transducers were used to measure expansion pressure and reflection pressure of working section near the end edge of the shock tube. Fractured specimens collected from the dump tank were investigated for the fracture phenomenon of ceramics after testing. The fracture pressure increases as a specimen thickness increases, and as the specimen diameter decreases, respectively. The driven gas pressures P2 obtained from theory and experiment agree well. The reflection wave pressures P5 agree well comparatively with both results of equation and experiment at low pressure of P4, but they do not agree well at high pressure of P4. The fracture phenomena of the plate and dome specimens at the same diameter are broken into small particles in various thicknesses, but the fracture phenomenon of the plate specimen is not broken into the particles as specimen diameter decreases.

  13. COMPRESSION WAVES AND PHASE PLOTS: SIMULATIONS

    SciTech Connect

    Orlikowski, D; Minich, R

    2011-08-01

    Compression wave analysis started nearly 50 years ago with Fowles. Coperthwaite and Williams gave a method that helps identify simple and steady waves. We have been developing a method that gives describes the non-isentropic character of compression waves, in general. One result of that work is a simple analysis tool. Our method helps clearly identify when a compression wave is a simple wave, a steady wave (shock), and when the compression wave is in transition. This affects the analysis of compression wave experiments and the resulting extraction of the high-pressure equation of state.

  14. Shock compression of polyvinyl chloride

    NASA Astrophysics Data System (ADS)

    Neogi, Anupam; Mitra, Nilanjan

    2016-04-01

    This study presents shock compression simulation of atactic polyvinyl chloride (PVC) using ab-initio and classical molecular dynamics. The manuscript also identifies the limits of applicability of classical molecular dynamics based shock compression simulation for PVC. The mechanism of bond dissociation under shock loading and its progression is demonstrated in this manuscript using the density functional theory based molecular dynamics simulations. The rate of dissociation of different bonds at different shock velocities is also presented in this manuscript.

  15. Shock compression of formic acid

    NASA Astrophysics Data System (ADS)

    Manner, Virginia W.; Sheffield, S. A.; Dattelbaum, Dana M.; Stahl, David B.

    2012-03-01

    Simple molecules such as formic acid, HCOOH, have been suggested to play important roles in the origin of life due to their high pressure and temperature chemistry. The hydrogen bonding characteristics and polymerization of HCOOH under static high pressure have been recently investigated using both molecular dynamics calculations and experimental work. These works suggest that symmetric hydrogen bonding of HCOOH (forming a linear chain polymer where all C-O bonds are equivalent) occurs at 16 - 21 GPa at room temperature. In order to examine the shock compression behavior of this simple carboxylic acid, we present a series of gas gun-driven plate impact experiments on formic acid with shock inputs in the range of 5.5 - 23.0 GPa. Using in-situ electromagnetic gauges, shock wave profiles (particle velocities) were measured at multiple positions as a function of shock input pressure, providing valuable information about its unreacted equation of state. No easily recognizable shock-induced reactions were observed in any of the four experiments, and the four points lie close to a universal liquid Hugoniot based only on the sound speed of formic acid.

  16. Shock Compression of Formic Acid

    NASA Astrophysics Data System (ADS)

    Manner, Virginia; Sheffield, Stephen; Dattelbaum, Dana; Engelke, Ray; Stahl, David; Shock; Detonation Physics Team

    2011-06-01

    Simple molecules such as formic acid, HCOOH, have been suggested to play important roles in the origin of life due to their high pressure and temperature chemistry. The hydrogen bonding characteristics and polymerization of HCOOH under high pressure have been recently investigated using both molecular dynamics calculations and experimental work. These works suggest that symmetric hydrogen bonding of HCOOH (forming a linear chain polymer where all C-O bonds are equivalent) occurs at 16 - 21 GPa at room temperature. In order to examine the shock compression behavior of this simple carboxylic acid, we present a series of gas gun-driven plate impact experiments on formic acid with shock inputs in the range of 10 - 20 GPa, overlapping in pressure with the earlier static experimental results. Using in-situ electromagnetic gauges, shock wave profiles (particle velocities) were measured at multiple Lagrangian positions as a function of shock input pressure, providing valuable information about its unreacted equation of state and shock-induced chemical reactions. The results are discussed in the context of the Hugoniot conditions, phase diagram and static high-pressure behavior, and related chemistry of other simple hydroxyl-/carboxyl-containing molecules.

  17. Spall strength and ejecta production of gold under explosively driven shock wave compression

    SciTech Connect

    La Lone, B. M.; Stevens, G. D.; Turley, W. D.; Veeser, L. R.; Holtkamp, D. B.

    2013-12-16

    Explosively driven shock wave experiments were conducted to characterize the spall strength and ejecta production of high-purity cast gold samples. The samples were from 0.75 to 1.84 mm thick and 30 mm in diameter. Peak stresses up to 44 GPa in gold were generated using PBX-9501 high explosive. Sample free surface and ejecta velocities were recorded using photonic Doppler velocimetry techniques. Lithium niobate pins were used to quantify the time dependence of the ejecta density and the total ejected mass. An optical framing camera for time-resolved imaging and a single-image x-ray radiograph were used for additional characterization. Free surface velocities exhibited a range of spall strengths from 1.7 to 2.4 GPa (mean: 2.0 ±0.3 GPa). The pullback signals were faint, minimal ringing was observed in the velocity records, and the spall layer continued to decelerate after first pull back. These results suggest finite tensile strength was present for some time after the initial void formation. Ejecta were observed for every sample with a roughened free surface, and the ejecta density increased with increased surface roughness, which was different in every experiment. The total ejected mass is consistent with the missing mass model.

  18. Shock compression and isentropic release of rhyolite

    NASA Astrophysics Data System (ADS)

    Yang, W.; Chen, G.; Anderson, W. W.; Ahrens, Thomas J.

    1994-07-01

    A series of shock compression experiments have been conducted on rhyolite at pressure ranging from 6 to 33 GPa. A velocity interferometer (VISAR) was employed to monitor the particle velocity of an aluminum reflector with a diffused surface bonded to the rhyolite sample. In the forward ballistic experiments, a slow rise shock wave front is observed at 6 GPa. While in the forward experiments their release waves are smeared, in a reverse ballistic experiment, the particle velocity variation at the shock wave plateau and the isentropic release wave arrival have been clearly observed. Using Swegle's mixed phase model, we simulated the experimental results with WONDY code. Like quartz and granite, the rhyolite data could be fit to a frozen release model which has some hysteric behavior. The Eulerian sound velocity at shock pressure 8.7 GPa has been determined to be 5.6 km/s.

  19. Shock wave compression of hexagonal-close-packed metal single crystals: Time-dependent, anisotropic elastic-plastic response of beryllium

    SciTech Connect

    Winey, J. M.; Gupta, Y. M.

    2014-07-21

    Understanding and modeling the response of hcp metals to high stress impulsive loading is challenging because the lower crystal symmetry, compared to cubic metals, results in a significantly more complex material response. To gain insight into the inelastic deformation of hcp metals subjected to high dynamic stresses, shock wave compression of single crystals provides a useful approach because different inelastic deformation mechanisms can be examined selectively by shock compression along different crystal orientations. As a representative example, we report, here, on wave propagation simulations for beryllium (Be) single crystals shocked along the c-axis, a-axis, and several low-symmetry directions to peak stresses reaching 7 GPa. The simulations utilized a time-dependent, anisotropic material model that incorporated dislocation dynamics, deformation twinning, and shear cracking based descriptions of inelastic deformation. The simulation results showed good overall agreement with measured wave profiles for all the different crystal orientations examined [Pope and Johnson, J. Appl. Phys. 46, 720 (1975)], including features arising from wave mode coupling due to the highly anisotropic inelastic response of Be. This good agreement demonstrates that the measured profiles can be understood in terms of dislocation slip along basal, prismatic, and pyramidal planes, together with deformation twinning along (101{sup ¯}2) planes. Our results show that the response of shocked Be single crystals involves the simultaneous operation of multiple, distinct inelastic deformation mechanisms for all orientations except the c-axis. For shocked c-axis Be, the measured wave profiles do not provide good discrimination between pyramidal slip and other inelastic deformation mechanisms, such as shear cracking. The findings presented here provide insight into the complex inelastic deformation response of shocked Be single crystals and are expected to be useful for other hcp crystals

  20. Modeling of chemical reactions in the mixture of Al-Ni powders under shock-wave compression

    SciTech Connect

    Horie, Y.; Kipp, M.E.

    1987-07-01

    Based upon microstructural observations of post-shock samples, a mathematical model was developed for chemical changes in the mixture of elemental Al and Ni powders from the passage of high-pressure shock-wave. The model was solved and illustrated using the one-dimensional Sandia code WONDY-IV.

  1. Shock compression profiles in ceramics

    SciTech Connect

    Grady, D.E.; Moody, R.L.

    1996-03-01

    An investigation of the shock compression properties of high-strength ceramics has been performed using controlled planar impact techniques. In a typical experimental configuration, a ceramic target disc is held stationary, and it is struck by plates of either a similar ceramic or by plates of a well-characterized metal. All tests were performed using either a single-stage propellant gun or a two-stage light-gas gun. Particle velocity histories were measured with laser velocity interferometry (VISAR) at the interface between the back of the target ceramic and a calibrated VISAR window material. Peak impact stresses achieved in these experiments range from about 3 to 70 GPa. Ceramics tested under shock impact loading include: Al{sub 2}O{sub 3}, AlN, B{sub 4}C, SiC, Si{sub 3}N{sub 4}, TiB{sub 2}, WC and ZrO{sub 2}. This report compiles the VISAR wave profiles and experimental impact parameters within a database-useful for response model development, computational model validation studies, and independent assessment of the physics of dynamic deformation on high-strength, brittle solids.

  2. Analysis of Temperature Measurement at LEAD/LiF Interface Under Shock Wave Compression

    NASA Astrophysics Data System (ADS)

    Chauvin, C.; Hereil, P. L.; Sinatti, F.

    2007-12-01

    Temperature is a fundamental parameter to validate the equation of state. A high-speed three-wavelength pyrometer has been improved at CEG to perform measurements at low temperature (<500 K) at the interface of a lead target and a LiF window at about 8 GPa. Besides, to reduce uncertainties of true temperature of this interface, the use of an emissive layer allows us to increase the emissivity of the shocked surface. The emissivity of the shocked interface is thereby restricted in the 0.9 and 1 range and improves the accuracy of the temperature measurement.

  3. Design and Testing of CO2 Compression Using Supersonic Shock Wave Technology

    SciTech Connect

    Koopman, Aaron

    2015-06-01

    This report summarizes work performed by Ramgen and subcontractors in pursuit of the design and construction of a 10 MW supersonic CO2 compressor and supporting facility. The compressor will demonstrate application of Ramgen’s supersonic compression technology at an industrial scale using CO2 in a closed-loop. The report includes details of early feasibility studies, CFD validation and comparison to experimental data, static test experimental results, compressor and facility design and analyses, and development of aerodynamic tools. A summary of Ramgen's ISC Engine program activity is also included. This program will demonstrate the adaptation of Ramgen's supersonic compression and advanced vortex combustion technology to result in a highly efficient and cost effective alternative to traditional gas turbine engines. The build out of a 1.5 MW test facility to support the engine and associated subcomponent test program is summarized.

  4. The interaction of laser radiation with explosively driven shock wave compressed Xe plasmas

    NASA Astrophysics Data System (ADS)

    Zaporozhets, Yu B.; Mintsev, V. B.; Gryaznov, V. K.; Reinholz, H.; Röpke, G.; Fortov, V. E.

    2016-11-01

    The analysis of the response of dense plasma to electromagnetic waves of moderate intensity can be used as a tool to investigate the validity of the physical models describing the behavior of matter under extreme conditions. Within this work the new experimental data on oblique incidence of polarized electromagnetic wave are presented. The study of polarized reflectivity properties of nonideal xenon plasma was accomplished using laser light at ν las = 2.83 × 1014 s-1 (λ las = 1064 nm) and ν las = 5.66 × 1014 s-1 (λ las = 532 nm). The measurements of polarized reflectivity coefficients of explosively driven dense plasmas have been carried out at incident angles up to θ = 78°. The plasma composition was calculated within a chemical picture. The integration of Maxwell equations to construct the spatial profile of the density of charge carriers of plasmas was based on an interpolation formula for DC conductivity.

  5. FLOW FIELD IN SUPERSONIC MIXED-COMPRESSION INLETS AT ANGLE OF ATTACK USING THE THREE DIMENSIONAL METHOD OF CHARACTERISTICS WITH DISCRETE SHOCK WAVE FITTING

    NASA Technical Reports Server (NTRS)

    Bishop, A. R.

    1994-01-01

    This computer program calculates the flow field in the supersonic portion of a mixed-compression aircraft inlet at non-zero angle of attack. This approach is based on the method of characteristics for steady three-dimensional flow. The results of this program agree with those produced by the two-dimensional method of characteristics when axisymmetric flow fields are calculated. Except in regions of high viscous interaction and boundary layer removal, the results agree well with experimental data obtained for threedimensional flow fields. The flow field in a variety of axisymmetric mixed compression inlets can be calculated using this program. The bow shock wave and the internal shock wave system are calculated using a discrete shock wave fitting procedure. The internal flow field can be calculated either with or without the discrete fitting of the internal shock wave system. The influence of molecular transport can be included in the calculation of the external flow about the forebody and in the calculation of the internal flow when internal shock waves are not discretely fitted. The viscous and thermal diffussion effects are included by treating them as correction terms in the method of characteristics procedure. Dynamic viscosity is represented by Sutherland's law and thermal conductivity is represented as a quadratic function of temperature. The thermodynamic model used is that of a thermally and calorically perfect gas. The program assumes that the cowl lip is contained in a constant plane and that the centerbody contour and cowl contour are smooth and have continuous first partial derivatives. This program cannot calculate subsonic flow, the external flow field if the bow shock wave does not exist entirely around the forebody, or the internal flow field if the bow flow field is injected into the annulus. Input to the program consists of parameters to control execution, to define the geometry, and the vehicle orientation. Output consists of a list of parameters

  6. FLOW FIELD IN SUPERSONIC MIXED-COMPRESSION INLETS AT ANGLE OF ATTACK USING THE THREE DIMENSIONAL METHOD OF CHARACTERISTICS WITH DISCRETE SHOCK WAVE FITTING

    NASA Technical Reports Server (NTRS)

    Bishop, A. R.

    1994-01-01

    This computer program calculates the flow field in the supersonic portion of a mixed-compression aircraft inlet at non-zero angle of attack. This approach is based on the method of characteristics for steady three-dimensional flow. The results of this program agree with those produced by the two-dimensional method of characteristics when axisymmetric flow fields are calculated. Except in regions of high viscous interaction and boundary layer removal, the results agree well with experimental data obtained for threedimensional flow fields. The flow field in a variety of axisymmetric mixed compression inlets can be calculated using this program. The bow shock wave and the internal shock wave system are calculated using a discrete shock wave fitting procedure. The internal flow field can be calculated either with or without the discrete fitting of the internal shock wave system. The influence of molecular transport can be included in the calculation of the external flow about the forebody and in the calculation of the internal flow when internal shock waves are not discretely fitted. The viscous and thermal diffussion effects are included by treating them as correction terms in the method of characteristics procedure. Dynamic viscosity is represented by Sutherland's law and thermal conductivity is represented as a quadratic function of temperature. The thermodynamic model used is that of a thermally and calorically perfect gas. The program assumes that the cowl lip is contained in a constant plane and that the centerbody contour and cowl contour are smooth and have continuous first partial derivatives. This program cannot calculate subsonic flow, the external flow field if the bow shock wave does not exist entirely around the forebody, or the internal flow field if the bow flow field is injected into the annulus. Input to the program consists of parameters to control execution, to define the geometry, and the vehicle orientation. Output consists of a list of parameters

  7. Uncertainty Assessments of 2D and Axisymmetric Hypersonic Shock Wave - Turbulent Boundary Layer Interaction Simulations at Compression Corners

    NASA Technical Reports Server (NTRS)

    Gnoffo, Peter A.; Berry, Scott A.; VanNorman, John W.

    2011-01-01

    This paper is one of a series of five papers in a special session organized by the NASA Fundamental Aeronautics Program that addresses uncertainty assessments for CFD simulations in hypersonic flow. Simulations of a shock emanating from a compression corner and interacting with a fully developed turbulent boundary layer are evaluated herein. Mission relevant conditions at Mach 7 and Mach 14 are defined for a pre-compression ramp of a scramjet powered vehicle. Three compression angles are defined, the smallest to avoid separation losses and the largest to force a separated flow engaging more complicated flow physics. The Baldwin-Lomax and the Cebeci-Smith algebraic models, the one-equation Spalart-Allmaras model with the Catrix-Aupoix compressibility modification and two-equation models including Menter SST, Wilcox k-omega 98, and Wilcox k-omega 06 turbulence models are evaluated. Each model is fully defined herein to preclude any ambiguity regarding model implementation. Comparisons are made to existing experimental data and Van Driest theory to provide preliminary assessment of model form uncertainty. A set of coarse grained uncertainty metrics are defined to capture essential differences among turbulence models. Except for the inability of algebraic models to converge for some separated flows there is no clearly superior model as judged by these metrics. A preliminary metric for the numerical component of uncertainty in shock-turbulent-boundary-layer interactions at compression corners sufficiently steep to cause separation is defined as 55%. This value is a median of differences with experimental data averaged for peak pressure and heating and for extent of separation captured in new, grid-converged solutions presented here. This value is consistent with existing results in a literature review of hypersonic shock-turbulent-boundary-layer interactions by Roy and Blottner and with more recent computations of MacLean.

  8. Rayleigh-Taylor Shock Waves

    SciTech Connect

    Olson, B J; Cook, A W

    2007-08-30

    Beginning from a state of hydrostatic equilibrium, in which a heavy gas rests atop a light gas in a constant gravitational field, Rayleigh-Taylor instability at the interface will launch a shock wave into the upper fluid. The rising bubbles of lighter fluid act like pistons, compressing the heavier fluid ahead of the fronts and generating shocklets. These shocklets coalesce in multidimensional fashion into a strong normal shock, which increases in strength as it propagates upwards. Large-eddy simulations demonstrate that the shock Mach number increases faster in three dimensions than it does in two dimensions. The generation of shocks via Rayleigh-Taylor instability could have profound implications for astrophysical flows.

  9. Laser-Driven Shock Compression Results on Deuterium

    NASA Astrophysics Data System (ADS)

    Hicks, D. G.; Celliers, P. M.; Collins, G. W.; Eggert, J. H.; Moon, S. J.; Foord, M. E.; Boehly, T. R.; Collins, T. J. B.; Vianello, E.; Jacobs-Perkins, D.; Meyerhofer, D. D.

    2003-10-01

    Laser-driven shock wave experiments have been performed at OMEGA to explore the equation of state of deuterium under double and single shock compression. We have developed a new technique of using a calibrated, high-pressure transparent material, quartz, which has enabled precision optical interferometer measurements of shock velocities. This approach significantly reduces the possibility of systematic error arising from shock unsteadiness. In the double-shock experiments, where quartz is used as a re-shock anvil, the results indicate deuterium has a compressibility that is close to the new SESAME and ab initio models below 1 Mbar but exhibits higher compressibility at larger pressures. In the single-shock, aluminum impedance-match experiments, quartz is used to accurately infer the shock velocity in aluminum; results from these recent experiments will be presented.

  10. Fabrication of graded density impactor via underwater shock wave and quasi-isentropic compression testing at two-stage gas gun facility

    NASA Astrophysics Data System (ADS)

    Sun, Wei; Li, Xiaojie; Hokamoto, Kazuyuki

    2014-12-01

    We show direct evidence that underwater shock wave enables us to bond multithin plates with flat, parallel, and high-strength interfaces, which are key requirements for functionally graded material (also called graded density impactor). This phenomenon is ascribed to the super short duration of the high-speed underwater shock wave, reducing the surface tension, diffusion, evaporation, deposition, and viscous flow of matter. Thin magnesium, aluminum, titanium, copper, and molybdenum foils were welded together and designed with the increase in density. Experimental evidence and numerical simulation show that well bonding between the multilayer structures. Microstructure examinations reveal that the dominant interfacial form shifts from waviness to linearity. Graded density impactor with multilayer structure is proved that can produce quasi-isentropic compression in two-stage gas gun experiment with a designed pressure loading profile, which suggests a feasible method to simulate the conditions we want to study that were previously inaccessible in a precisely controlled laboratory environment.

  11. New Developments in the Physical Chemistry of Shock Compression

    NASA Astrophysics Data System (ADS)

    Dlott, Dana D.

    2011-05-01

    This review discusses new developments in shock compression science with a focus on molecular media. Some basic features of shock and detonation waves, nonlinear excitations that can produce extreme states of high temperature and high pressure, are described. Methods of generating and detecting shock waves are reviewed, especially those using tabletop lasers that can be interfaced with advanced molecular diagnostics. Newer compression methods such as shockless compression and precompression shock that generate states of cold dense molecular matter are discussed. Shock compression creates a metallic form of hydrogen, melts diamond, and makes water a superionic liquid with unique catalytic properties. Our understanding of detonations at the molecular level has improved a great deal as a result of advanced nonequilibrium molecular simulations. Experimental measurements of detailed molecular behavior behind a detonation front might be available soon using femtosecond lasers to produce nanoscale simulated detonation fronts.

  12. New developments in the physical chemistry of shock compression.

    PubMed

    Dlott, Dana D

    2011-01-01

    This review discusses new developments in shock compression science with a focus on molecular media. Some basic features of shock and detonation waves, nonlinear excitations that can produce extreme states of high temperature and high pressure, are described. Methods of generating and detecting shock waves are reviewed, especially those using tabletop lasers that can be interfaced with advanced molecular diagnostics. Newer compression methods such as shockless compression and precompression shock that generate states of cold dense molecular matter are discussed. Shock compression creates a metallic form of hydrogen, melts diamond, and makes water a superionic liquid with unique catalytic properties. Our understanding of detonations at the molecular level has improved a great deal as a result of advanced nonequilibrium molecular simulations. Experimental measurements of detailed molecular behavior behind a detonation front might be available soon using femtosecond lasers to produce nanoscale simulated detonation fronts.

  13. When shock waves collide

    SciTech Connect

    Martinez, D.; Hartigan, P.; Frank, A.; Hansen, E.; Yirak, K.; Liao, A. S.; Graham, P.; Foster, J.; Wilde, B.; Blue, B.; Rosen, P.; Farley, D.; Paguio, R.

    2016-06-01

    Supersonic outflows from objects as varied as stellar jets, massive stars, and novae often exhibit multiple shock waves that overlap one another. When the intersection angle between two shock waves exceeds a critical value, the system reconfigures its geometry to create a normal shock known as a Mach stem where the shocks meet. Mach stems are important for interpreting emission-line images of shocked gas because a normal shock produces higher postshock temperatures, and therefore a higher-excitation spectrum than does an oblique shock. In this paper, we summarize the results of a series of numerical simulations and laboratory experiments designed to quantify how Mach stems behave in supersonic plasmas that are the norm in astrophysical flows. The experiments test analytical predictions for critical angles where Mach stems should form, and quantify how Mach stems grow and decay as intersection angles between the incident shock and a surface change. While small Mach stems are destroyed by surface irregularities and subcritical angles, larger ones persist in these situations and can regrow if the intersection angle changes to become more favorable. Furthermore, the experimental and numerical results show that although Mach stems occur only over a limited range of intersection angles and size scales, within these ranges they are relatively robust, and hence are a viable explanation for variable bright knots observed in Hubble Space Telescope images at the intersections of some bow shocks in stellar jets.

  14. When Shock Waves Collide

    NASA Astrophysics Data System (ADS)

    Hartigan, P.; Foster, J.; Frank, A.; Hansen, E.; Yirak, K.; Liao, A. S.; Graham, P.; Wilde, B.; Blue, B.; Martinez, D.; Rosen, P.; Farley, D.; Paguio, R.

    2016-06-01

    Supersonic outflows from objects as varied as stellar jets, massive stars, and novae often exhibit multiple shock waves that overlap one another. When the intersection angle between two shock waves exceeds a critical value, the system reconfigures its geometry to create a normal shock known as a Mach stem where the shocks meet. Mach stems are important for interpreting emission-line images of shocked gas because a normal shock produces higher postshock temperatures, and therefore a higher-excitation spectrum than does an oblique shock. In this paper, we summarize the results of a series of numerical simulations and laboratory experiments designed to quantify how Mach stems behave in supersonic plasmas that are the norm in astrophysical flows. The experiments test analytical predictions for critical angles where Mach stems should form, and quantify how Mach stems grow and decay as intersection angles between the incident shock and a surface change. While small Mach stems are destroyed by surface irregularities and subcritical angles, larger ones persist in these situations and can regrow if the intersection angle changes to become more favorable. The experimental and numerical results show that although Mach stems occur only over a limited range of intersection angles and size scales, within these ranges they are relatively robust, and hence are a viable explanation for variable bright knots observed in Hubble Space Telescope images at the intersections of some bow shocks in stellar jets.

  15. When shock waves collide

    DOE PAGES

    Martinez, D.; Hartigan, P.; Frank, A.; ...

    2016-06-01

    Supersonic outflows from objects as varied as stellar jets, massive stars, and novae often exhibit multiple shock waves that overlap one another. When the intersection angle between two shock waves exceeds a critical value, the system reconfigures its geometry to create a normal shock known as a Mach stem where the shocks meet. Mach stems are important for interpreting emission-line images of shocked gas because a normal shock produces higher postshock temperatures, and therefore a higher-excitation spectrum than does an oblique shock. In this paper, we summarize the results of a series of numerical simulations and laboratory experiments designed tomore » quantify how Mach stems behave in supersonic plasmas that are the norm in astrophysical flows. The experiments test analytical predictions for critical angles where Mach stems should form, and quantify how Mach stems grow and decay as intersection angles between the incident shock and a surface change. While small Mach stems are destroyed by surface irregularities and subcritical angles, larger ones persist in these situations and can regrow if the intersection angle changes to become more favorable. Furthermore, the experimental and numerical results show that although Mach stems occur only over a limited range of intersection angles and size scales, within these ranges they are relatively robust, and hence are a viable explanation for variable bright knots observed in Hubble Space Telescope images at the intersections of some bow shocks in stellar jets.« less

  16. When shock waves collide

    SciTech Connect

    Martinez, D.; Hartigan, P.; Frank, A.; Hansen, E.; Yirak, K.; Liao, A. S.; Graham, P.; Foster, J.; Wilde, B.; Blue, B.; Rosen, P.; Farley, D.; Paguio, R.

    2016-06-01

    Supersonic outflows from objects as varied as stellar jets, massive stars, and novae often exhibit multiple shock waves that overlap one another. When the intersection angle between two shock waves exceeds a critical value, the system reconfigures its geometry to create a normal shock known as a Mach stem where the shocks meet. Mach stems are important for interpreting emission-line images of shocked gas because a normal shock produces higher postshock temperatures, and therefore a higher-excitation spectrum than does an oblique shock. In this paper, we summarize the results of a series of numerical simulations and laboratory experiments designed to quantify how Mach stems behave in supersonic plasmas that are the norm in astrophysical flows. The experiments test analytical predictions for critical angles where Mach stems should form, and quantify how Mach stems grow and decay as intersection angles between the incident shock and a surface change. While small Mach stems are destroyed by surface irregularities and subcritical angles, larger ones persist in these situations and can regrow if the intersection angle changes to become more favorable. Furthermore, the experimental and numerical results show that although Mach stems occur only over a limited range of intersection angles and size scales, within these ranges they are relatively robust, and hence are a viable explanation for variable bright knots observed in Hubble Space Telescope images at the intersections of some bow shocks in stellar jets.

  17. Analysis of Shock to Detonation Transition (SDT) of Porous High Energy Propellant from Ramp-Wave Compression Loading.

    DTIC Science & Technology

    1984-09-01

    define the hydrodynamics and thermodynamic state of a continuous, porous medium. A finite difference technique patterned after the WONDY code [27...combination of a quadratic equation, taken from Reference [28] (which essentially spreads the shock wave) and a linear equation, taken from WONDY [27] and...Growth in the Initiation of Explosives, Sixth Symposium (International) on Detonation, (1976), 47-59. 27. Klpp, M. E., and Lawrence, R. J., " WONDY V, A One

  18. Shock Wave Initiation of Mixture Liquid Explosives

    NASA Astrophysics Data System (ADS)

    Fedorov, A. V.; Mikhailov, A. L.; Nazarov, D. V.; Finyushin, S. A.; Men'shikh, A. V.; Davydov, V. A.

    2006-07-01

    We investigated initiation of liquid HE consisting of tetranitromethane (TNM) and nitrobenzene (NB). Smooth stable (when mass of NB<20%) and pulsing unstable detonation wave front was registered (20-50% NB). We registered shock wave, shock compressed explosive (SCE) detonation wave and normal detonation wave for unstable detonation front on different parts of the front. In case of normal and SCE detonation wave we registered parameters rise during 3-25 nsec until the start of chemical reaction. We consider it to be the induction period of thermal explosion inside detonation wave front.

  19. Shock and Static Compression of Nitrobenzene

    NASA Astrophysics Data System (ADS)

    Kozu, Naoshi; Arai, Mitsuru; Tamura, Masamitsu; Fujihisa, Hiroshi; Aoki, Katsutoshi; Yoshida, Masatake

    2000-08-01

    The Hugoniot and static compression curve (isotherm) were investigated using explosive plane wave generators and diamond anvil cells, respectively. The obtained Hugoniot from the shock experiments is represented by two linear lines: Us=2.52+1.23 up (0.8shock velocity and the particle velocity in km/s, respectively. A kink exists at around 15 GPa. The line for the higher particle velocities agrees well with the Hugoniot of detonation products calculated by the CHEETAH code. This suggests that nitrobenzene detonates in this range. Under static high pressure over 7 GPa, nitrobenzene undergoes a reaction that is expected to be polymerization. Considering the Hugoniot and the isotherm, it is plausible that shocked nitrobenzene (<15 GPa) is in the liquid state.

  20. The behavior of a compressible turbulent boundary layer in a shock-wave-induced adverse pressure gradient. Ph.D. Thesis - Washington Univ., Seattle, Aug. 1972

    NASA Technical Reports Server (NTRS)

    Rose, W. C.

    1973-01-01

    The results of an experimental investigation of the mean- and fluctuating-flow properties of a compressible turbulent boundary layer in a shock-wave-induced adverse pressure gradient are presented. The turbulent boundary layer developed on the wall of an axially symmetric nozzle and test section whose nominal free-stream Mach number and boundary-layer thickness Reynolds number were 4 and 100,000, respectively. The adverse pressure gradient was induced by an externally generated conical shock wave. Mean and time-averaged fluctuating-flow data, including the complete experimental Reynolds stress tensor and experimental turbulent mass- and heat-transfer rates are presented for the boundary layer and external flow, upstream, within and downstream of the pressure gradient. The mean-flow data include distributions of total temperature throughout the region of interest. The turbulent mixing properties of the flow were determined experimentally with a hot-wire anemometer. The calibration of the wires and the interpretation of the data are discussed. From the results of the investigation, it is concluded that the shock-wave - boundary-layer interaction significantly alters the turbulent mixing characteristics of the boundary layer.

  1. TIMING OF SHOCK WAVES

    DOEpatents

    Tuck, J.L.

    1955-03-01

    This patent relates to means for ascertaining the instant of arrival of a shock wave in an exploslve charge and apparatus utilizing this means to coordinate the timing of two operations involving a short lnterval of time. A pair of spaced electrodes are inserted along the line of an explosive train with a voltage applied there-across which is insufficient to cause discharge. When it is desired to initiate operation of a device at the time the explosive shock wave reaches a particular point on the explosive line, the device having an inherent time delay, the electrodes are located ahead of the point such that the ionization of the area between the electrodes caused by the traveling explosive shock wave sends a signal to initiate operation of the device to cause it to operate at the proper time. The operated device may be photographic equipment consisting of an x-ray illuminating tube.

  2. Shock compression and quasielastic release in tantalum

    SciTech Connect

    Johnson, J.N.; Hixson, R.S.; Tonks, D.L.; Gray, G.T. III

    1993-06-01

    Previous studies of quasielastic release in shock-loaded FCC metals have shown a strong influence of the defect state on the leading edge, or first observable arrival, of release wave, due to large density of pinned dislocation segments behind the shock front, their relatively large pinning separation, and a very short response time as determined by drag coefficient in shock-compressed state. This effect is entirely equivalent to problems associated with elastic moduli determination using ultrasonic methods. This is particularly true for FCC metals, which have an especially low Peierls stress, or inherent lattice resistance, that has little influence in pinning dislocation segments and inhibiting anelastic deformation. BCC metals, on the other hand, have a large Peierls stress that essentially holds dislocation segments in place at low net applied shear stresses and thus allows fully elastic deformation to occur in the complete absence of anelastic behavior. Shock-compression and release experiments have been performed on tantalum (BCC), with the observation that the leading release disturbance is indeed elastic. This conclusion is established by examination of experimental VISAR records taken at the tantalum/sapphire (window) interface in a symmetric-impact experiment which subjects the sample to a peak longitudinal stress of approximately 7.3 GPa, in comparison with characteristic code calculations.

  3. The Acoustics of Shock Wave Lithotripsy

    NASA Astrophysics Data System (ADS)

    Cleveland, Robin O.

    2007-04-01

    The shock waves employed in lithotripsy are high amplitude acoustics waves. As they propagate through the body to the stone that are affected by coupling to the body and the presence of tissue through which they must pass. Once the shock wave arrives at the stone there is a complex transmission of energy into the stone as the shock wave can couple into compression and shear waves in the stone and produce cavitation in the surrounding fluid. The surrounding tissue is also subject to large physical forces that can result in damage. Physical phenomena that play a role include: generation of sound, nonlinear distortion, attenuation, diffraction, coupling into the body, transmission and mode conversion into the stone. This paper gives a synopsis of some of the relevant physics that applies to shock wave lithotripsy.

  4. Shock wave interactions with liquid sheets

    NASA Astrophysics Data System (ADS)

    Jeon, H.; Eliasson, V.

    2017-04-01

    Shock wave interactions with a liquid sheet are investigated by impacting planar liquid sheets of varying thicknesses with a planar shock wave. A square frame was designed to hold a rectangular liquid sheet, with a thickness of 5 or 10 mm, using plastic membranes and cotton wires to maintain the planar shape and minimize bulge. The flat liquid sheet, consisting of either water or a cornstarch and water mixture, was suspended in the test section of a shock tube. Incident shock waves with Mach numbers of M_s = 1.34 and 1.46 were considered. A schlieren technique with a high-speed camera was used to visualize the shock wave interaction with the liquid sheets. High-frequency pressure sensors were used to measure wave speed, overpressure, and impulse both upstream and downstream of the liquid sheet. Results showed that no transmitted shock wave could be observed through the liquid sheets, but compression waves induced by the shock-accelerated liquid coalesced into a shock wave farther downstream. A thicker liquid sheet resulted in a lower peak overpressure and impulse, and a cornstarch suspension sheet showed a higher attenuation factor compared to a water sheet.

  5. Micromechanical strength effects in shock compression of solids

    SciTech Connect

    Johnson, J.N.

    1993-06-01

    Time-resolved shock-wave measurements and post-shock recovery have long been used for inferring the underlaying micromechanics controlling high-rate deformation of solids; this requires considerable subjective interpretation. In spite of this, progress has been made in experimentation and theoretical interpretation of the shock-compression/release cycle and some of the results are reviewed here for weak shocks. This cycle involves the elements of the elastic precursor, plastic loading wave, pulse duration, release wave, and post-mortem examination. Those topics are examined, with emphasis on the second and fourth elements. Cu and Ta results show how shock data can be used to determine the transition from deformation mechanism of thermal activation to that of dislocation drag. Release-wave studies indicate that the leading observable release disturbance in fcc metals may not be propagating with the ideal longitudinal elastic-wave speed. 5 figs, 18 refs.

  6. Micromechanical strength effects in shock compression of solids

    SciTech Connect

    Johnson, J.N.

    1993-01-01

    Time-resolved shock-wave measurements and post-shock recovery have long been used for inferring the underlaying micromechanics controlling high-rate deformation of solids; this requires considerable subjective interpretation. In spite of this, progress has been made in experimentation and theoretical interpretation of the shock-compression/release cycle and some of the results are reviewed here for weak shocks. This cycle involves the elements of the elastic precursor, plastic loading wave, pulse duration, release wave, and post-mortem examination. Those topics are examined, with emphasis on the second and fourth elements. Cu and Ta results show how shock data can be used to determine the transition from deformation mechanism of thermal activation to that of dislocation drag. Release-wave studies indicate that the leading observable release disturbance in fcc metals may not be propagating with the ideal longitudinal elastic-wave speed. 5 figs, 18 refs.

  7. Exhaust Nozzle Plume and Shock Wave Interaction

    NASA Technical Reports Server (NTRS)

    Castner, Raymond S.; Elmiligui, Alaa; Cliff, Susan

    2013-01-01

    Fundamental research for sonic boom reduction is needed to quantify the interaction of shock waves generated from the aircraft wing or tail surfaces with the exhaust plume. Both the nozzle exhaust plume shape and the tail shock shape may be affected by an interaction that may alter the vehicle sonic boom signature. The plume and shock interaction was studied using Computational Fluid Dynamics simulation on two types of convergent-divergent nozzles and a simple wedge shock generator. The nozzle plume effects on the lower wedge compression region are evaluated for two- and three-dimensional nozzle plumes. Results show that the compression from the wedge deflects the nozzle plume and shocks form on the deflected lower plume boundary. The sonic boom pressure signature of the wedge is modified by the presence of the plume, and the computational predictions show significant (8 to 15 percent) changes in shock amplitude.

  8. Whistler Waves Associated with Weak Interplanetary Shocks

    NASA Technical Reports Server (NTRS)

    Velez, J. C. Ramirez; Blanco-Cano, X.; Aguilar-Rodriguez, E.; Russell, C. T.; Kajdic, P.; Jian,, L. K.; Luhmann, J. G.

    2012-01-01

    We analyze the properties of 98 weak interplanetary shocks measured by the dual STEREO spacecraft over approximately 3 years during the past solar minimum. We study the occurrence of whistler waves associated with these shocks, which on average are high beta shocks (0.2 < Beta < 10). We have compared the waves properties upstream and downstream of the shocks. In the upstream region the waves are mainly circularly polarized, and in most of the cases (approx. 75%) they propagate almost parallel to the ambient magnetic field (<30 deg.). In contrast, the propagation angle with respect to the shock normal varies in a broad range of values (20 deg. to 90 deg.), suggesting that they are not phase standing. We find that the whistler waves can extend up to 100,000 km in the upstream region but in most cases (88%) are contained in a distance within 30,000 km from the shock. This corresponds to a larger region with upstream whistlers associated with IP shocks than previously reported in the literature. The maximum amplitudes of the waves are observed next to the shock interface, and they decrease as the distance to the shock increases. In most cases the wave propagation direction becomes more aligned with the magnetic field as the distance to the shock increases. These two facts suggest that most of the waves in the upstream region are Landau damping as they move away from the shock. From the analysis we also conclude that it is likely that the generation mechanism of the upstream whistler waves is taking place at the shock interface. In the downstream region, the waves are irregularly polarized, and the fluctuations are very compressive; that is, the compressive component of the wave clearly dominates over the transverse one. The majority of waves in the downstream region (95%) propagate at oblique angles with respect to the ambient magnetic field (>60 deg.). The wave propagation with respect to the shock-normal direction has no preferred direction and varies similarly to

  9. Static and shock compressibility of TATB molecular crystal

    NASA Astrophysics Data System (ADS)

    Degtyarev, A. A.; Smirnov, E. B.; Kostitsin, O. V.; Stankevich, A. V.; Muzyrya, A. K.; Ten, K. A.; Pruuel, E. R.; Kashkarov, A. O.; Batretdinova, L. H.

    2016-11-01

    The paper presents analysis of experimental data on hydrostatic and shock-wave compression of TATB energy-saturated material. The semi-empirical Mie-Grüneisen equation of state was used to describe thermodynamic properties of metastable molecular crystals without considering phase transitions. The equation of state describes experimental data on isothermal compression of a molecular crystal, and this data are obtained using the powder diffraction method. The Hugoniot curve expression plausibly describes shock-compression data on the studied material having various initial porosities.

  10. Shock Propagation and Instability Structures in Compressed Silica Aerogels

    SciTech Connect

    Howard, W M; Molitoris, J D; DeHaven, M R; Gash, A E; Satcher, J H

    2002-05-30

    We have performed a series of experiments examining shock propagation in low density aerogels. High-pressure ({approx}100 kbar) shock waves are produced by detonating high explosives. Radiography is used to obtain a time sequence imaging of the shocks as they enter and traverse the aerogel. We compress the aerogel by impinging shocks waves on either one or both sides of an aerogel slab. The shock wave initially transmitted to the aerogel is very narrow and flat, but disperses and curves as it propagates. Optical images of the shock front reveal the initial formation of a hot dense region that cools and evolves into a well-defined microstructure. Structures observed in the shock front are examined in the framework of hydrodynamic instabilities generated as the shock traverses the low-density aerogel. The primary features of shock propagation are compared to simulations, which also include modeling the detonation of the high explosive, with a 2-D Arbitrary Lagrange Eulerian hydrodynamics code The code includes a detailed thermochemical equation of state and rate law kinetics. We will present an analysis of the data from the time resolved imaging diagnostics and form a consistent picture of the shock transmission, propagation and instability structure.

  11. Radiative Shock Waves In Emerging Shocks

    NASA Astrophysics Data System (ADS)

    Drake, R. Paul; Doss, F.; Visco, A.

    2011-05-01

    In laboratory experiments we produce radiative shock waves having dense, thin shells. These shocks are similar to shocks emerging from optically thick environments in astrophysics in that they are strongly radiative with optically thick shocked layers and optically thin or intermediate downstream layers through which radiation readily escapes. Examples include shocks breaking out of a Type II supernova (SN) and the radiative reverse shock during the early phases of the SN remnant produced by a red supergiant star. We produce these shocks by driving a low-Z plasma piston (Be) at > 100 km/s into Xe gas at 1.1 atm. pressure. The shocked Xe collapses to > 20 times its initial density. Measurements of structure by radiography and temperature by several methods confirm that the shock wave is strongly radiative. We observe small-scale perturbations in the post-shock layer, modulating the shock and material interfaces. We describe a variation of the Vishniac instability theory of decelerating shocks and an analysis of associated scaling relations to account for the growth of these perturbations, identify how they scale to astrophysical systems such as SN 1993J, and consider possible future experiments. Collaborators in this work have included H.F. Robey, J.P. Hughes, C.C. Kuranz, C.M. Huntington, S.H. Glenzer, T. Doeppner, D.H. Froula, M.J. Grosskopf, and D.C. Marion ________________________________ * Supported by the US DOE NNSA under the Predictive Sci. Academic Alliance Program by grant DE-FC52-08NA28616, the Stewardship Sci. Academic Alliances program by grant DE-FG52-04NA00064, and the Nat. Laser User Facility by grant DE-FG03-00SF22021.

  12. Shock wave-boundary layer interaction in forced shock oscillations

    NASA Astrophysics Data System (ADS)

    Doerffer, Piotr; Szulc, Oskar; Magagnato, Franco

    2003-02-01

    The flow in transonic diffusers as well as in supersonic air intakes becomes often unsteady due to shock wave boundary layer interaction. The oscillations may be induced by natural separation unsteadiness or may be forced by boundary conditions. Significant improvement of CFD tools, increase of computer resources as well as development of experimental methods have again drawn the attention of researchers to this topic. To investigate the problem forced oscillations of transonic turbulent flow in asymmetric two-dimensional Laval nozzle were considered. A viscous, perfect gas flow, was numerically simulated using the Reynolds-averaged compressible Navier-Stokes solver SPARC, employing a two-equation, eddy viscosity, turbulence closure in the URANS approach. For time-dependent and stationary flow simulations, Mach numbers upstream of the shock between 1.2 and 1.4 were considered. Comparison of computed and experimental data for steady states generally gave acceptable agreement. In the case of forced oscillations, a harmonic pressure variation was prescribed at the exit plane resulting in shock wave motion. Excitation frequencies between 0 Hz and 1024 Hz were investigated at the same pressure amplitude. The main result of the work carried out is the relation between the amplitude of the shock wave motion and the excitation frequency in the investigated range. Increasing excitation frequency resulted in decreasing amplitude of the shock movement. At high frequencies a natural mode of shock oscillation (of small amplitude) was observed which is not sensitive to forced excitement.

  13. Piston Dispersive Shock Wave Problem

    SciTech Connect

    Hoefer, M. A.; Ablowitz, M. J.; Engels, P.

    2008-02-29

    The piston shock problem is a classical result of shock wave theory. In this work, the analogous dispersive shock wave (DSW) problem for a fluid described by the nonlinear Schroedinger equation is analyzed. Asymptotic solutions are calculated for a piston (step potential) moving with uniform speed into a dispersive fluid at rest. In contrast to the classical case, there is a bifurcation of shock behavior where, for large enough piston velocities, the DSW develops a periodic wave train in its wake with vacuum points and a maximum density that remains fixed as the piston velocity is increased further. These results have application to Bose-Einstein condensates and nonlinear optics.

  14. Shock-wave properties of soda-lime glass

    SciTech Connect

    Grady, D.E.; Chhabildas, L.C.

    1996-11-01

    Planar impact experiments and wave profile measurements provided single and double shock equation of state data to 30 GPa. Both compression wave wave profile structure and release wave data were used to infer time-dependent strength and equation of state properties for soda-lime glass.

  15. SPHERICAL SHOCK WAVES IN SOLIDS

    DTIC Science & Technology

    Contents: Introduction-Reasons for Studying Spherical Shock Waves, Physics of Cavity Expansion due to Explosive Impact, General Nature of Shock Waves...Governing Differential Equation of Self-Similar Motion; Application of the Theory of Self-Similar Motion to the Problem of Expansion of a Spherical

  16. Shock wave strengthening through area reduction

    NASA Astrophysics Data System (ADS)

    Skews, B. W.; Subiah, S. D.; Paton, R. T.

    2017-02-01

    Experiments were conducted in a shock tube in order to determine the increases in shock wave strength due to reductions in area. Previous work has shown that if the reduction is too sudden significant wave reflections occur and gains are limited. A variety of curved symmetrical contractions are used, made up of parabolic surfaces with different points of inflection. High-speed Schlieren imaging was used to characterize the wave patterns with particular emphasis on wave reflections. Greatest wave amplification is present when Mach reflection of the wave is not reached at all, and this was found to occur with parabolic profiles with inflection point at 60% of the profile length. Clear Mach reflection is evident with the inflection point at 40% and the post shock flow shows significant reflected waves with their associated losses. With an area reduction of 80% and a inflection point at 60% of the contraction, a typical result gives an increase in Mach number from 1.6 to 2.0, corresponding to a 61% increase in post-shock pressure. It is found that profiles with later inflection points provide a more gradual initial area change and allow weaker compression waves to develop which can significantly reduce or even avoid transition to Mach reflection.

  17. Atomistic molecular dynamics simulations of shock compressed quartz

    NASA Astrophysics Data System (ADS)

    Farrow, M. R.; Probert, M. I. J.

    2011-07-01

    Atomistic non-equilibrium molecular dynamics simulations of shock wave compression of quartz have been performed using the so-called BKS semi-empirical potential of van Beest, Kramer, and van Santen [Phys. Rev. B 43, 5068 (1991)], 10.1103/PhysRevB.43.5068 to construct the Hugoniot of quartz. Our scheme mimics the real world experimental set up by using a flyer-plate impactor to initiate the shock wave and is the first shock wave simulation that uses a geometry optimised system of a polar slab in a three-dimensional system employing periodic boundary conditions. Our scheme also includes the relaxation of the surface dipole in the polar quartz slab which is an essential pre-requisite to a stable simulation. The original BKS potential is unsuited to shock wave calculations and so we propose a simple modification. With this modification, we find that our calculated Hugoniot is in good agreement with experimental shock wave data up to 25 GPa, but significantly diverges beyond this point. We conclude that our modified BKS potential is suitable for quartz under representative pressure conditions of the Earth core, but unsuitable for high-pressure shock wave simulations. We also find that the BKS potential incorrectly prefers the β-quartz phase over the α-quartz phase at zero-temperature, and that there is a β → α phase-transition at 6 GPa.

  18. Isentropic compressive wave generator and method of making same

    DOEpatents

    Barker, L.M.

    An isentropic compressive wave generator and method of making same are disclosed. The wave generator comprises a disk or flat pillow member having component materials of different shock impedances formed in a configuration resulting in a smooth shock impedance gradient over the thickness thereof for interpositioning between an impactor member and a target specimen for producing a shock wave of a smooth predictable rise time. The method of making the pillow member comprises the reduction of the component materials to a powder form and forming the pillow member by sedimentation and compressive techniques.

  19. Shock Wave Structure in Particulate Composites

    NASA Astrophysics Data System (ADS)

    Rauls, Michael; Ravichandran, Guruswami

    2015-06-01

    Shock wave experiments are conducted on a particulate composite consisting of a polymethyl methacrylate (PMMA) matrix reinforced by glass beads. Such a composite with an impedance mismatch of 4.3 closely mimics heterogeneous solids of interest such as concrete and energetic materials. The composite samples are prepared using a compression molding process. The structure and particle velocity rise times of the shocks are examined using forward ballistic experiments. Reverse ballistic experiments are used to track how the interface density influences velocity overshoot above the steady state particle velocity. The effects of particle size (0.1 to 1 mm) and volume fraction of glass beads (30-40%) on the structure of the leading shock wave are investigated. It is observed that the rise time increases with increasing particle size and scales linearly for the range of particle sizes considered here. Results from numerical simulations using CTH are compared with experimental results to gain insights into wave propagation in heterogeneous particulate composites.

  20. Shock compression and release in high-strength ceramics

    SciTech Connect

    Kipp, M E; Grady, D E

    1989-08-01

    A preliminary investigation of shock compression and release properties has been performed on four ceramics: silicon carbide, titanium diboride, boron carbide and zirconium dioxide. Eight planar impact experiments using thin discs of similar ceramic as impactor and target have been completed. The particle velocity history at the interface between the back of the target ceramic and a lithium fluoride window material was acquired with a laser velocity interferometer (VISAR). These wave profiles indicate that each of these materials responds in a unique way to shock loading. Peak impact stresses in these experiments range between 20 and 50 GPa, leading to pronounced permanent deformation behavior of these materials. Dynamic compression and release stress-strain behavior of the ceramics, formulated with numerical iteration methods, is compared with compressive strength properties determined from the experimental data. The current experiments provide data for these ceramic materials which can be used to evaluate computational material models in wave propagation codes. 23 refs., 25 figs., 4 tabs.

  1. Some aspects of shock-wave research

    NASA Astrophysics Data System (ADS)

    Glass, I. I.

    1986-01-01

    Examples are given of shock-wave phenomena on Earth and in space. A specific shock-wave research problem, namely, pseudostationary oblique shock-wave reflections in perfect and imperfect gases is presented. Consideration is given to what has been achieved to date by using two- and three-shock theory to predict what type of reflection results when a planar shock wave M sub s, in a shock tube, collides with a sharp compressive wedge of angle, theta sub w. Experimental (interferometric and other optical) data are presented in (M sub s, theta sub w)-plots for argon, nitrogen, oxygen, air carbon-dioxide, Freon 12 and sulfurhexafluoride, in order to check the validity of the analytically predicted regions and transition lines of the four types of reflection (RR, SMR, CMR, DMR). Some disagreements are noted and discussed. Our interferometric isopycnic data are also compared with state-of-the-art computational results from a solution of the inviscid Euler equations using a CRAY I computer. Good agreement was obtained, yet, it would be important to obtain new data by solving the Navier-Stokes equations, as well as the rate equations for imperfect-gas excitations, in order to judge the improvement obtained with real-flow interferograms.

  2. Magnetically accelerated foils for shock wave experiments

    NASA Astrophysics Data System (ADS)

    Neff, Stephan; Ford, Jessica; Martinez, David; Plechaty, Christopher; Wright, Sandra; Presura, Radu

    2008-04-01

    The interaction of shock waves with inhomogeneous media is important in many astrophysical problems, e.g. the role of shock compression in star formation. Using scaled experiments with inhomogeneous foam targets makes it possible to study relevant physics in the laboratory, to better understand the mechanisms of shock compression and to benchmark astrophysical simulation codes. Experiments with flyer-generated shock waves have been performed on the Z machine in Sandia. The Zebra accelerator at the Nevada Terawatt Facility (NTF) allows for complementary experiments with high repetition rate. First experiments on Zebra demonstrated flyer acceleration to sufficiently high velocities (around 2 km/s) and that laser shadowgraphy can image sound fronts in transparent targets. Based on this, we designed an optimized setup to improve the flyer parameters (higher speed and mass) to create shock waves in transparent media. Once x-ray backlighting with the Leopard laser at NTF is operational, we will switch to foam targets with parameters relevant for laboratory astrophysics.

  3. Shock compression response of Ti+B reactive powder mixtures

    NASA Astrophysics Data System (ADS)

    Gonzales, M.; Gurumurthy, A.; Kennedy, G. B.; Gokhale, A. M.; Thadhani, N. N.

    2014-05-01

    The shock compression response of Ti+2B (1:2 Ti:B stoichiometric ratio) reactive powder mixtures at ~50% theoretical material density (TMD) is investigated for shock pressures up to 5 GPa to investigate the possible shock-induced chemical reactivity of this highly exothermic mixture. The shock adiabat is produced from instrumented parallel-plate gas-gun impact experiments on encapsulated powders using poly-vinylidene fluoride (PVDF) stress gauges to measure the input and propagated stresses and wave speed in the powder. The shock compression regime is probed from crush-up to full density and onward to assess the potential onset of a shock-induced chemical reaction event in the powder mixture. A series of two-dimensional continuum meso-scale simulations on validated simulated microstructures are performed to predict the shock compression response and identify the meso-scale mechanics that are essential for reaction. The suitability of the synthetic microstructural representations is evaluated by comparing the experimental and predicted pressure traces.

  4. Shock compression response of Ti+B reactive powder mixtures

    NASA Astrophysics Data System (ADS)

    Gonzales, Manny; Gurumurthy, Ashok; Kennedy, Gregory; Gokhale, Arun; Thadhani, Naresh

    2013-06-01

    The shock compression response of Ti+2B (1:2 Ti:B stoichiometric ratio) reactive powder mixtures at ~50% theoretical material density (TMD) is investigated for shock pressures up to 5 GPa to investigate the possible shock-induced chemical reactivity of this highly exothermic mixture. The shock adiabat is produced from instrumented parallel-plate gas-gun impact experiments on encapsulated powders using poly-vinylidene fluoride (PVDF) stress gauges to measure the input and propagated stress and wave speed in the powder. The shock compression regime is probed from crush-up to full density and onward to assess the potential onset of a shock-induced chemical reaction event in the powder mixture. A series of two-dimensional continuum meso-scale simulations on real and simulated microstructures are performed to predict the shock compression response and identify the meso-scale mechanics that is essential for the so-called ``ballotechnic'' reaction. These meso-scale mechanics are investigated through stereological evolution metrics that track particle interface evolution and their respective field variables. The suitability of the synthetic microstructural representations is evaluated by comparing the experimental and predicted pressure traces. We gratefully acknowledge support and funding from DTRA through Grant No. HDTRA1-10-1-0038 and the National Defense Science and Engineering Graduate (NDSEG) Fellowship through the High Performance Computing and Modernization Office (HPCMO).

  5. Shock waves: The Maxwell-Cattaneo case

    NASA Astrophysics Data System (ADS)

    Uribe, F. J.

    2016-03-01

    Several continuum theories for shock waves give rise to a set of differential equations in which the analysis of the underlying vector field can be done using the tools of the theory of dynamical systems. We illustrate the importance of the divergences associated with the vector field by considering the ideas by Maxwell and Cattaneo and apply them to study shock waves in dilute gases. By comparing the predictions of the Maxwell-Cattaneo equations with shock wave experiments we are lead to the following conclusions: (a) For low compressions (low Mach numbers: M ) the results from the Maxwell-Cattaneo equations provide profiles that are in fair agreement with the experiments, (b) as the Mach number is increased we find a range of Mach numbers (1.27 ≈M1shock wave solutions to the Maxwell-Cattaneo equations cannot be found, and (c) for greater Mach numbers (M >M2) shock wave solutions can be found though they differ significantly from experiments.

  6. Shock waves: The Maxwell-Cattaneo case.

    PubMed

    Uribe, F J

    2016-03-01

    Several continuum theories for shock waves give rise to a set of differential equations in which the analysis of the underlying vector field can be done using the tools of the theory of dynamical systems. We illustrate the importance of the divergences associated with the vector field by considering the ideas by Maxwell and Cattaneo and apply them to study shock waves in dilute gases. By comparing the predictions of the Maxwell-Cattaneo equations with shock wave experiments we are lead to the following conclusions: (a) For low compressions (low Mach numbers: M) the results from the Maxwell-Cattaneo equations provide profiles that are in fair agreement with the experiments, (b) as the Mach number is increased we find a range of Mach numbers (1.27 ≈ M(1) < M < M(2) ≈ 1.90) such that numerical shock wave solutions to the Maxwell-Cattaneo equations cannot be found, and (c) for greater Mach numbers (M>M_{2}) shock wave solutions can be found though they differ significantly from experiments.

  7. Density Shock Waves in Confined Microswimmers

    NASA Astrophysics Data System (ADS)

    Tsang, Alan Cheng Hou; Kanso, Eva

    2016-01-01

    Motile and driven particles confined in microfluidic channels exhibit interesting emergent behavior, from propagating density bands to density shock waves. A deeper understanding of the physical mechanisms responsible for these emergent structures is relevant to a number of physical and biomedical applications. Here, we study the formation of density shock waves in the context of an idealized model of microswimmers confined in a narrow channel and subject to a uniform external flow. Interestingly, these density shock waves exhibit a transition from "subsonic" with compression at the back to "supersonic" with compression at the front of the population as the intensity of the external flow increases. This behavior is the result of a nontrivial interplay between hydrodynamic interactions and geometric confinement, and it is confirmed by a novel quasilinear wave model that properly captures the dependence of the shock formation on the external flow. These findings can be used to guide the development of novel mechanisms for controlling the emergent density distribution and the average population speed, with potentially profound implications on various processes in industry and biotechnology, such as the transport and sorting of cells in flow channels.

  8. Flow behind concave shock waves

    NASA Astrophysics Data System (ADS)

    Mölder, S.

    2017-09-01

    Curved shock theory is introduced and applied to calculate the flow behind concave shock waves. For sonic conditions, three characterizing types of flow are identified, based on the orientation of the sonic line, and it is shown that, depending on the ratio of shock curvatures, a continuously curving shock can exist with Type III flow, where the sonic line intercepts the reflected characteristics from the shock, thus preventing the formation of a reflected shock. The necessary shock curvature ratio for a Type III sonic point does not exist for a hyperbolic shock so that it will revert to Mach reflection for all Mach numbers. A demonstration is provided, by CFD calculations, at Mach 1.2 and 3.

  9. Flow behind concave shock waves

    NASA Astrophysics Data System (ADS)

    Mölder, S.

    2017-03-01

    Curved shock theory is introduced and applied to calculate the flow behind concave shock waves. For sonic conditions, three characterizing types of flow are identified, based on the orientation of the sonic line, and it is shown that, depending on the ratio of shock curvatures, a continuously curving shock can exist with Type III flow, where the sonic line intercepts the reflected characteristics from the shock, thus preventing the formation of a reflected shock. The necessary shock curvature ratio for a Type III sonic point does not exist for a hyperbolic shock so that it will revert to Mach reflection for all Mach numbers. A demonstration is provided, by CFD calculations, at Mach 1.2 and 3.

  10. Response to ``Comment on `Thermal nonequilibrium of the shock-compressed state polymers realized by 1 GPa shock waves' '' [J. Appl. Phys. 88, 2177 (2000)

    NASA Astrophysics Data System (ADS)

    Nagayama, Kunihito; Mori, Yasuhito

    2000-08-01

    In the previous article, we showed that a very large Grüneisen parameter for poly(methylmethacrylate) is estimated for a very large slope in shock-particle velocity Hugoniot below the kink point at 150 m/s. This large gamma corresponds to the intermolecular vibrational mode, which is supposed to be excited almost exclusively at the shock front. Rosenberg claimed that his shock temperature measurement by gauge method showed no deflection, which could be observed across the Hugoniot kink, if the above condition is fulfilled. Thermal energy transfer between intermolecular to intramolecular vibrational modes does not occur in the time scale realized in experiments. Then, thermalization between the nonequilibrium polymer region and the gauge material is expected to have similar or longer relaxation time than stress relaxation. Rosenberg's temperature records seem to support this scenario.

  11. Magnetically accelerated foils for shock wave experiments

    NASA Astrophysics Data System (ADS)

    Neff, S.; Ford, J.; Wright, S.; Martinez, D.; Plechaty, C.; Presura, R.

    2009-08-01

    Many astrophysical phenomena involve the interaction of a shock wave with an inhomogeneous background medium. Using scaled experiments with inhomogeneous foam targets makes it possible to study relevant physics in the laboratory to better understand the mechanisms of shock compression and to benchmark astrophysical simulation codes. First experiments on Zebra at the Nevada Terawatt Facility (NTF) have demonstrated flyer acceleration to sufficiently high velocities (up to 5 km/s) and that laser shadowgraphy can image sound fronts in transparent targets. Based on this, we designed an optimized setup to improve the flyer parameters (higher speed and mass) to create shock waves in transparent media. Once x-ray backlighting with the Leopard laser at NTF is operational, we will switch to foam targets with parameters relevant for laboratory astrophysics.

  12. Gene-culture shock waves

    NASA Astrophysics Data System (ADS)

    Straughan, B.

    2013-11-01

    A hyperbolic model is presented which generalises Aoki's parabolic system for the combined propagation of a mutant gene together with a cultural innovation. It is shown that this model allows for the propagation of a shock wave and the shock amplitude is calculated numerically. Particular attention is paid to the case where the shock moves into a region where the frequencies of the mutant gene and of the individuals adopting the innovation are zero.

  13. Stress relaxation in vanadium under shock and shockless dynamic compression

    SciTech Connect

    Kanel, G. I.; Razorenov, S. V.; Garkushin, G. V.; Savinykh, A. S.; Zaretsky, E. B.

    2015-07-28

    Evolutions of elastic-plastic waves have been recorded in three series of plate impact experiments with annealed vanadium samples under conditions of shockless and combined ramp and shock dynamic compression. The shaping of incident wave profiles was realized using intermediate base plates made of different silicate glasses through which the compression waves were entered into the samples. Measurements of the free surface velocity histories revealed an apparent growth of the Hugoniot elastic limit with decreasing average rate of compression. The growth was explained by “freezing” of the elastic precursor decay in the area of interaction of the incident and reflected waves. A set of obtained data show that the current value of the Hugoniot elastic limit and plastic strain rate is rather associated with the rate of the elastic precursor decay than with the local rate of compression. The study has revealed the contributions of dislocation multiplications in elastic waves. It has been shown that independently of the compression history the material arrives at the minimum point between the elastic and plastic waves with the same density of mobile dislocations.

  14. Shock Compression of Simulated Adobe

    NASA Astrophysics Data System (ADS)

    Braithwaite, C. H.; Church, P. D.; Gould, P. J.; Stewart, B.; Jardine, A. P.

    2015-06-01

    A series of plate impact experiments were conducted to investigate the shock response of a simulant for adobe, a traditional form of building material widely used around the world. Air dried bricks were sourced from the London brick company, dry machined and impacted at a range of velocities in a single stage gas gun. The shock Hugoniot was determined (Us = 2.26up + 0.33) as well as release information. The material was found to behave in a manner which was similar to that of loose sand and considerably less stiff than a weak porous sandstone. The effect of any cementing of the grains was examined by shocking powdered samples contained within a cell arrangement. The research was funded by DSTL through a WSTC contract.

  15. Shock compression of simulated adobe

    NASA Astrophysics Data System (ADS)

    Braithwaite, C. H.; Church, P. D.; Gould, P. J.; Stewart, B.; Jardine, A. P.

    2017-01-01

    A series of plate impact experiments were conducted to investigate the shock response of a simulant for adobe, a traditional form of building material widely used around the world. Air dried bricks were sourced from the London brick company, dry machined and impacted at a range of velocities in a single stage gas gun. The shock Hugoniot was determined (Us =2.26up+0.37) as well as release information. The material was found to behave in a manner which was similar to that of loose sand and considerably less stiff than a weak porous sandstone. The effect of any cementing of the grains was examined by shocking powdered samples contained within a cell arrangement.

  16. Historical Background of Ultrahigh Pressure Shock Compression Experiments at LLNL: 1973 to 2000

    SciTech Connect

    Nellis, W.J.

    2000-10-09

    My purpose is to recount the historical development of ultrahigh pressure shock compression experiments at LLNL, which I experienced in the period 1973 to 2000. I used several experimental techniques: shock-impedance-match experiments using planar shock waves driven by nuclear explosives (NIMs), the Janus Laser, a railgun, and a two-stage light-gas gun.

  17. Shock waves show icebreaking promise

    SciTech Connect

    Wesley, R.H.; Stowell, W.R.

    1985-11-01

    State-of-the-art technology that is readily applicable in other offshore areas does not function adequately in Arctic regions. The common offshore problem in the Arctic, whether it be related to transportation, construction, drilling or production, is ice. Technology utilizing the phenomenal characteristics of the shock wave now exists that will allow relief from the ice problem in all of these categories. The feasibility of using shock waves for icebreaking is discussed.

  18. Compressive passive millimeter wave imager

    DOEpatents

    Gopalsami, Nachappa; Liao, Shaolin; Elmer, Thomas W; Koehl, Eugene R; Heifetz, Alexander; Raptis, Apostolos C

    2015-01-27

    A compressive scanning approach for millimeter wave imaging and sensing. A Hadamard mask is positioned to receive millimeter waves from an object to be imaged. A subset of the full set of Hadamard acquisitions is sampled. The subset is used to reconstruct an image representing the object.

  19. A cosmic string shock wave

    NASA Astrophysics Data System (ADS)

    Deruelle, Nathalie; Linet, Bernard

    1988-01-01

    The theory of general relativistic shock waves is used to model the supersonic wake of a straight cosmic string. The motion of a supersonic fluid past an element of a cosmic string at rest, a problem which is equivalent to the motion of a cosmic string in a fluid at rest, is first investigated. The method is then demonstrated by treating the case of an infinite straight string. It is shown both that the density contrast is enhanced by the shock and that the pressure behind the shock wave is much greater than in front.

  20. Shock waves in polycrystalline iron.

    PubMed

    Kadau, Kai; Germann, Timothy C; Lomdahl, Peter S; Albers, Robert C; Wark, Justin S; Higginbotham, Andrew; Holian, Brad Lee

    2007-03-30

    The propagation of shock waves through polycrystalline iron is explored by large-scale atomistic simulations. For large enough shock strengths the passage of the wave causes the body-centered-cubic phase to transform into a close-packed phase with most structure being isotropic hexagonal-close-packed (hcp) and, depending on shock strength and grain orientation, some fraction of face-centered-cubic (fcc) structure. The simulated shock Hugoniot is compared to experiments. By calculating the extended x-ray absorption fine structure (EXAFS) directly from the atomic configurations, a comparison to experimental EXAFS measurements of nanosecond-laser shocks shows that the experimental data is consistent with such a phase transformation. However, the atomistically simulated EXAFS spectra also show that an experimental distinction between the hcp or fcc phase is not possible based on the spectra alone.

  1. Some aspects of shock-wave research

    NASA Astrophysics Data System (ADS)

    Glass, I. I.

    1986-01-01

    The major portion of the paper is devoted to a specific shock-wave research problem, namely, pseudostationary oblique shock-wave reflections in perfect and imperfect gases. Consideration is given to what has been achieved to date by using two- and three-shock theory to predict what type of reflection results when a planar shock wave M(S), in a shock tube, collides with a sharp compressive wedge of angle, theta(W). Expermental (interferometric and other optical) data are presented in (M(S), theta(W))-plots for argon, nitrogen, oxygen, air, carbon-dioxide, Freon-12 and sulfurhexafluoride, in order to check the validity of the analytically predicted regions and transition lines of the four types of reflection. Some disagreements are noted and discussed. The present interferometric isopycnic data are also compared with state-of-the-art computational results from a solution of the inviscid Euler equations using a CRAY I computer. Good agreement was obtained; it would be important, however, to obtain new data by solving the Navier-Stokes equations, as well as the rate equations for imperfect-gas excitations, in order to judge the improvement obtained with real-flow interferograms.

  2. Shock wave formation in the collapse of a vapor nanobubble.

    PubMed

    Magaletti, F; Marino, L; Casciola, C M

    2015-02-13

    In this Letter, the dynamics of a collapsing vapor bubble is addressed by means of a diffuse-interface formulation. The model cleanly captures, through a unified approach, all the critical features of the process, such as phase change, transition to supercritical conditions, thermal conduction, compressibility effects, and shock wave formation and propagation. Rather unexpectedly for pure vapor bubbles, the numerical experiments show that the process consists in the oscillation of the bubble associated with the emission of shock waves in the liquid, and with the periodic disappearance and reappearance of the liquid-vapor interface due to transition to super- or subcritical conditions. The results identify the mechanism of shock wave formation as strongly related to the transition of the vapor to the supercritical state, with a progressive steepening of a focused compression wave evolving into a shock which is eventually reflected as an outward propagating wave in the liquid.

  3. Hugoniot Measurements of Silicon Shock Compressed to 25 Mbar

    NASA Astrophysics Data System (ADS)

    Henderson, B.; Polsin, D. N.; Boehly, T. R.; Gregor, M. C.; Hu, S. X.; Collins, G. W.; Rygg, J. R.; Fratanduono, D. E.; Celliers, P. M.

    2016-10-01

    We present results of laser-driven shock experiments that compressed silicon samples to 25 Mbar. Impedance matching to a quartz reference provided Hugoniot data. Since silicon is opaque, a quartz witness was placed adjacent to the silicon samples; this afforded the use of the unsteady wave correction to increase the precision of the transit-time measurements of shock velocity. Results are compared both SESAME tables and to quantum molecular dynamics calculations. This material is based upon work supported by the Department Of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  4. Directional amorphization of boron carbide subjected to laser shock compression

    DOE PAGES

    Zhao, Shiteng; Kad, Bimal; Remington, Bruce A.; ...

    2016-10-12

    Solid-state shock-wave propagation is strongly nonequilibrium in nature and hence rate dependent. When using high-power pulsed-laser-driven shock compression, an unprecedented high strain rates can be achieved; we report the directional amorphization in boron carbide polycrystals. At a shock pressure of 45~50 GPa, multiple planar faults, slightly deviated from maximum shear direction, occur a few hundred nanometers below the shock surface. High-resolution transmission electron microscopy reveals that these planar faults are precursors of directional amorphization. We also propose that the shear stresses cause the amorphization and that pressure assists the process by ensuring the integrity of the specimen. Thermal energy conversionmore » calculations including heat transfer suggest that amorphization is a solid-state process. Such a phenomenon has significant effect on the ballistic performance of B4C.« less

  5. Directional amorphization of boron carbide subjected to laser shock compression

    NASA Astrophysics Data System (ADS)

    Zhao, Shiteng; Kad, Bimal; Remington, Bruce A.; LaSalvia, Jerry C.; Wehrenberg, Christopher E.; Behler, Kristopher D.; Meyers, Marc A.

    2016-10-01

    Solid-state shock-wave propagation is strongly nonequilibrium in nature and hence rate dependent. Using high-power pulsed-laser-driven shock compression, unprecedented high strain rates can be achieved; here we report the directional amorphization in boron carbide polycrystals. At a shock pressure of 45˜50 GPa, multiple planar faults, slightly deviated from maximum shear direction, occur a few hundred nanometers below the shock surface. High-resolution transmission electron microscopy reveals that these planar faults are precursors of directional amorphization. It is proposed that the shear stresses cause the amorphization and that pressure assists the process by ensuring the integrity of the specimen. Thermal energy conversion calculations including heat transfer suggest that amorphization is a solid-state process. Such a phenomenon has significant effect on the ballistic performance of B4C.

  6. Modeling shock waves in orthotropic elastic materials

    NASA Astrophysics Data System (ADS)

    Vignjevic, Rade; Campbell, James C.; Bourne, Neil K.; Djordjevic, Nenad

    2008-08-01

    A constitutive relationship for modeling of shock wave propagation in orthotropic materials is proposed for nonlinear explicit transient large deformation computer codes (hydrocodes). A procedure for separation of material volumetric compression (compressibility effects equation of state) from deviatoric strain effects is formulated, which allows for the consistent calculation of stresses in the elastic regime as well as in the presence of shock waves. According to this procedure the pressure is defined as the state of stress that results in only volumetric deformation, and consequently is a diagonal second order tensor. As reported by Anderson et al. [Comput. Mech. 15, 201 (1994)], the shock response of an orthotropic material cannot be accurately predicted using the conventional decomposition of the stress tensor into isotropic and deviatoric parts. This paper presents two different stress decompositions based on the assumption that the stress tensor is split into two components: one component is due to volumetric strain and the other is due to deviatoric strain. Both decompositions are rigorously derived. In order to test their ability to describe shock propagation in orthotropic materials, both algorithms were implemented in a hydrocode and their predictions were compared to experimental plate impact data. The material considered was a carbon fiber reinforced epoxy material, which was tested in both the through-thickness and longitudinal directions. The ψ decomposition showed good agreement with the physical behavior of the considered material, while the ζ decomposition significantly overestimated the longitudinal stresses.

  7. Diaphragmless shock wave generators for industrial applications of shock waves

    NASA Astrophysics Data System (ADS)

    Hariharan, M. S.; Janardhanraj, S.; Saravanan, S.; Jagadeesh, G.

    2011-06-01

    The prime focus of this study is to design a 50 mm internal diameter diaphragmless shock tube that can be used in an industrial facility for repeated loading of shock waves. The instantaneous rise in pressure and temperature of a medium can be used in a variety of industrial applications. We designed, fabricated and tested three different shock wave generators of which one system employs a highly elastic rubber membrane and the other systems use a fast acting pneumatic valve instead of conventional metal diaphragms. The valve opening speed is obtained with the help of a high speed camera. For shock generation systems with a pneumatic cylinder, it ranges from 0.325 to 1.15 m/s while it is around 8.3 m/s for the rubber membrane. Experiments are conducted using the three diaphragmless systems and the results obtained are analyzed carefully to obtain a relation between the opening speed of the valve and the amount of gas that is actually utilized in the generation of the shock wave for each system. The rubber membrane is not suitable for industrial applications because it needs to be replaced regularly and cannot withstand high driver pressures. The maximum shock Mach number obtained using the new diaphragmless system that uses the pneumatic valve is 2.125 ± 0.2%. This system shows much promise for automation in an industrial environment.

  8. Rupture-disk-less shock-tube with compression tube driven by free piston

    NASA Astrophysics Data System (ADS)

    Abe, T.; Ogura, E.; Sato, S.; Funabiki, K.

    A new technique is proposed for a shock tube driven by a freely moving piston. In a conventional free-piston-driven shock tube, a rupture disk is employed between the compression tube and the shock generation tube. In the present method, however, the conventional rupture disk is replaced by a newly developed fast action valve which is activated by the compressed gas generated in the compression tube. The present method enables us to generate high Mach number shock waves of arbitrary strength with good reproducibility. The performance of the new method is demonstrated experimentally. This also enables us to be carefree to scattering of fragments of the rupture disk.

  9. Properties of Fluid Deuterium under Double-Shock Compression to Several Mbar

    SciTech Connect

    Vianello, E; Celliers, P M; Hicks, D G; Boehly, T R; Collins, T B; Moon, S J; Eggert, J H; Collins, G W; Meyerhofer, D D

    2004-02-03

    The compressibility of fluid deuterium up to several Mbar has been probed using laser-driven shock waves reflected from a quartz anvil. Combining high-precision ({approx} 1 %) shock velocity measurements with the double-shock technique, where differences in equation of state (EOS) models are magnified, has allowed us to accurately discriminate between various theoretical predictions. Our data are consistent with EOS models that show approximately fourfold compression on the principal Hugoniot from 0.7 to 1 Mbar; however, our results indicate that deuterium has a higher compressibility than predicted by these models for single shock pressures between 1 and 2.5 Mbar.

  10. Shock wave-droplet interaction

    NASA Astrophysics Data System (ADS)

    Habibi Khoshmehr, Hamed; Krechetnikov, Rouslan

    2016-11-01

    Disintegration of a liquid droplet under the action of a shock wave is experimentally investigated. The shock wave-pulse is electromagnetically generated by discharging a high voltage capacitor into a flat spiral coil, above which an isolated circular metal membrane is placed in a close proximity. The Lorentz force arising due to the eddy current induced in the membrane abruptly accelerates it away from the spiral coil thus generating a shock wave. The liquid droplet placed at the center of the membrane, where the maximum deflection occurs, is disintegrated in the process of interaction with the shock wave. The effects of droplet viscosity and surface tension on the droplet destruction are studied with high-speed photography. Water-glycerol solution at different concentrations is used for investigating the effect of viscosity and various concentrations of water-sugar and water-ethanol solution are used for studying the effect of surface tension. Here we report on how the metamorphoses, which a liquid drop undergoes in the process of interaction with a shock wave, are affected by varied viscosity and surface tension.

  11. International Shock-Wave Database: Current Status

    NASA Astrophysics Data System (ADS)

    Levashov, Pavel

    2013-06-01

    Shock-wave and related dynamic material response data serve for calibrating, validating, and improving material models over very broad regions of the pressure-temperature-density phase space. Since the middle of the 20th century vast amount of shock-wave experimental information has been obtained. To systemize it a number of compendiums of shock-wave data has been issued by LLNL, LANL (USA), CEA (France), IPCP and VNIIEF (Russia). In mid-90th the drawbacks of the paper handbooks became obvious, so the first version of the online shock-wave database appeared in 1997 (http://www.ficp.ac.ru/rusbank). It includes approximately 20000 experimental points on shock compression, adiabatic expansion, measurements of sound velocity behind the shock front and free-surface-velocity for more than 650 substances. This is still a useful tool for the shock-wave community, but it has a number of serious disadvantages which can't be easily eliminated: (i) very simple data format for points and references; (ii) minimalistic user interface for data addition; (iii) absence of history of changes; (iv) bad feedback from users. The new International Shock-Wave database (ISWdb) is intended to solve these and some other problems. The ISWdb project objectives are: (i) to develop a database on thermodynamic and mechanical properties of materials under conditions of shock-wave and other dynamic loadings, selected related quantities of interest, and the meta-data that describes the provenance of the measurements and material models; and (ii) to make this database available internationally through the Internet, in an interactive form. The development and operation of the ISWdb is guided by an advisory committee. The database will be installed on two mirrored web-servers, one in Russia and the other in USA (currently only one server is available). The database provides access to original experimental data on shock compression, non-shock dynamic loadings, isentropic expansion, measurements of sound

  12. Uniform shock waves in disordered granular matter.

    PubMed

    Gómez, Leopoldo R; Turner, Ari M; Vitelli, Vincenzo

    2012-10-01

    The confining pressure P is perhaps the most important parameter controlling the properties of granular matter. Strongly compressed granular media are, in many respects, simple solids in which elastic perturbations travel as ordinary phonons. However, the speed of sound in granular aggregates continuously decreases as the confining pressure decreases, completely vanishing at the jamming-unjamming transition. This anomalous behavior suggests that the transport of energy at low pressures should not be dominated by phonons. In this work we use simulations and theory to show how the response of granular systems becomes increasingly nonlinear as pressure decreases. In the low-pressure regime the elastic energy is found to be mainly transported through nonlinear waves and shocks. We numerically characterize the propagation speed, shape, and stability of these shocks and model the dependence of the shock speed on pressure and impact intensity by a simple analytical approach.

  13. Interaction of a swept shock wave and a supersonic wake

    NASA Astrophysics Data System (ADS)

    He, G.; Zhao, Y. X.; Zhou, J.

    2017-09-01

    The interaction of a swept shock wave and a supersonic wake has been studied. The swept shock wave is generated by a swept compression sidewall, and the supersonic wake is generated by a wake generator. The flow field is visualized with the nanoparticle-based planar laser scattering method, and a supplementary numerical simulation is conducted by solving the Reynolds-averaged Navier-Stokes equations. The results show that the pressure rise induced by the swept shock wave can propagate upstream in the wake, which makes the location where vortices are generated move upstream, thickens the laminar section of the wake, and enlarges the generated vortices. The wake is swept away from the swept compression sidewall by the pressure gradient of the swept shock wave. This pressure gradient is not aligned with the density gradient of the supersonic wake, so the baroclinic torque generates streamwise vorticity and changes the distribution of the spanwise vorticity. The wake shock is curved, so the flow downstream of it is non-uniform, leaving the swept shock wave being distorted. A three-dimensional Mach disk structure is generated when the wake shock interacts with the swept shock wave.

  14. Interaction of a swept shock wave and a supersonic wake

    NASA Astrophysics Data System (ADS)

    He, G.; Zhao, Y. X.; Zhou, J.

    2017-03-01

    The interaction of a swept shock wave and a supersonic wake has been studied. The swept shock wave is generated by a swept compression sidewall, and the supersonic wake is generated by a wake generator. The flow field is visualized with the nanoparticle-based planar laser scattering method, and a supplementary numerical simulation is conducted by solving the Reynolds-averaged Navier-Stokes equations. The results show that the pressure rise induced by the swept shock wave can propagate upstream in the wake, which makes the location where vortices are generated move upstream, thickens the laminar section of the wake, and enlarges the generated vortices. The wake is swept away from the swept compression sidewall by the pressure gradient of the swept shock wave. This pressure gradient is not aligned with the density gradient of the supersonic wake, so the baroclinic torque generates streamwise vorticity and changes the distribution of the spanwise vorticity. The wake shock is curved, so the flow downstream of it is non-uniform, leaving the swept shock wave being distorted. A three-dimensional Mach disk structure is generated when the wake shock interacts with the swept shock wave.

  15. Planar shock wave sliding over a water layer

    NASA Astrophysics Data System (ADS)

    Rodriguez, V.; Jourdan, G.; Marty, A.; Allou, A.; Parisse, J.-D.

    2016-08-01

    In this work, we conduct experiments to study the interaction between a horizontal free water layer and a planar shock wave that is sliding over it. Experiments are performed at atmospheric pressure in a shock tube with a square cross section (200× 200 mm^2) for depths of 10, 20, and 30 mm; a 1500-mm-long water layer; and two incident planar shock waves having Mach numbers of 1.11 and 1.43. We record the pressure histories and high-speed visualizations to study the flow patterns, surface waves, and spray layers behind the shock wave. We observe two different flow patterns with ripples formed at the air-water interface for the weaker shock wave and the dispersion of a droplet mist for the stronger shock wave. From the pressure signals, we extract the delay time between the arrival of the compression wave into water and the shock wave in air at the same location. We show that the delay time evolves with the distance traveled over the water layer, the depth of the water layer, and the Mach number of the shock wave.

  16. Shock compression experiments on Lithium Deuteride single crystals.

    SciTech Connect

    Knudson, Marcus D.; Desjarlais, Michael Paul; Lemke, Raymond W.

    2014-10-01

    S hock compression exper iments in the few hundred GPa (multi - Mabr) regime were performed on Lithium Deuteride (LiD) single crystals . This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17 - 32 km/s. Measurements included pressure, density, and temperature between %7E200 - 600 GPa along the Principal Hugoniot - the locus of end states achievable through compression by large amplitude shock waves - as well as pressure and density of re - shock states up to %7E900 GPa . The experimental measurements are compared with recent density functional theory calculations as well as a new tabular equation of state developed at Los Alamos National Labs.

  17. History of shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Delius, Michael

    2000-07-01

    The first reports on the fragmentation of human calculi with ultrasound appeared in the fifties. Initial positive results with an extracorporeal approach with continuous wave ultrasound could, however, not be reproduced. A more promising result was found by generating the acoustic energy either in pulsed or continuous form directly at the stone surface. The method was applied clinically with success. Extracorporeal shock-wave generators unite the principle of using single ultrasonic pulses with the principle of generating the acoustic energy outside the body and focusing it through the skin and body wall onto the stone. Häusler and Kiefer reported the first successful contact-free kidney stone destruction by shock waves. They had put the stone in a water filled cylinder and generated a shock wave with a high speed water drop which was fired onto the water surface. To apply the new principle in medicine, both Häusler and Hoff's group at Dornier company constructed different shock wave generators for the stone destruction; the former used a torus-shaped reflector around an explosion wire, the latter the electrode-ellipsoid system. The former required open surgery to access the kidney stone, the latter did not. It was introduced into clinical practice after a series of experiments in Munich.

  18. Shock compression of [001] single crystal silicon

    SciTech Connect

    Zhao, S.; Remington, B.; Hahn, E. N.; Kad, B.; Bringa, E. M.; Meyers, M. A.

    2016-03-14

    Silicon is ubiquitous in our advanced technological society, yet our current understanding of change to its mechanical response at extreme pressures and strain-rates is far from complete. This is due to its brittleness, making recovery experiments difficult. High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon (using impedance-matched momentum traps) unveiled remarkable structural changes observed by transmission electron microscopy. As laser energy increases, corresponding to an increase in peak shock pressure, the following plastic responses are are observed: surface cleavage along {111} planes, dislocations and stacking faults; bands of amorphized material initially forming on crystallographic orientations consistent with dislocation slip; and coarse regions of amorphized material. Molecular dynamics simulations approach equivalent length and time scales to laser experiments and reveal the evolution of shock-induced partial dislocations and their crucial role in the preliminary stages of amorphization. Furthermore, application of coupled hydrostatic and shear stresses produce amorphization below the hydrostatically determined critical melting pressure under dynamic shock compression.

  19. Shock compression of [001] single crystal silicon

    DOE PAGES

    Zhao, S.; Remington, B.; Hahn, E. N.; ...

    2016-03-14

    Silicon is ubiquitous in our advanced technological society, yet our current understanding of change to its mechanical response at extreme pressures and strain-rates is far from complete. This is due to its brittleness, making recovery experiments difficult. High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon (using impedance-matched momentum traps) unveiled remarkable structural changes observed by transmission electron microscopy. As laser energy increases, corresponding to an increase in peak shock pressure, the following plastic responses are are observed: surface cleavage along {111} planes, dislocations and stacking faults; bands of amorphized material initially forming on crystallographic orientations consistent withmore » dislocation slip; and coarse regions of amorphized material. Molecular dynamics simulations approach equivalent length and time scales to laser experiments and reveal the evolution of shock-induced partial dislocations and their crucial role in the preliminary stages of amorphization. Furthermore, application of coupled hydrostatic and shear stresses produce amorphization below the hydrostatically determined critical melting pressure under dynamic shock compression.« less

  20. Shock compression of [001] single crystal silicon

    NASA Astrophysics Data System (ADS)

    Zhao, S.; Hahn, E. N.; Kad, B.; Remington, B. A.; Bringa, E. M.; Meyers, M. A.

    2016-05-01

    Silicon is ubiquitous in our advanced technological society, yet our current understanding of change to its mechanical response at extreme pressures and strain-rates is far from complete. This is due to its brittleness, making recovery experiments difficult. High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon (using impedance-matched momentum traps) unveiled remarkable structural changes observed by transmission electron microscopy. As laser energy increases, corresponding to an increase in peak shock pressure, the following plastic responses are are observed: surface cleavage along {111} planes, dislocations and stacking faults; bands of amorphized material initially forming on crystallographic orientations consistent with dislocation slip; and coarse regions of amorphized material. Molecular dynamics simulations approach equivalent length and time scales to laser experiments and reveal the evolution of shock-induced partial dislocations and their crucial role in the preliminary stages of amorphization. Application of coupled hydrostatic and shear stresses produce amorphization below the hydrostatically determined critical melting pressure under dynamic shock compression.

  1. Optical distortion in the field of a lithotripter shock wave

    NASA Astrophysics Data System (ADS)

    Carnell, M. T.; Emmony, D. C.

    1995-10-01

    The schlieren observation of cavitation phenomena produced in the tail of a lithotripter shock wave has indicated the presence of some interesting features. The images produced appear to indicate that cavitation transients in the field of a shock wave propagate nonsymmetrically; this is not the case. The apparent lack of symmetry exhibited by the primary cavitation transients is due to a complex optical lensing effect, which is brought about by the change in refractive index associated with the pressure profile of the shock wave. Objects seen through or immersed in the shock-wave field of an electromagnetic acoustic transducer, such as cavitation, appear highly distorted because of the strong positive and negative lensing effects of the compression and rarefaction cycles of the shock wave. A modification of the schlieren technique called the scale method has been used to model the distortion introduced by the shock wave and consequently explain the cavitation distortion. The technique has also been used to quantitatively analyze and partially reconstruct the lithotripter shock wave. The combination of schlieren and scale imaging gives more information about the refractive index field and therefore the shock-wave structure itself.

  2. Shock compression properties of silicon carbide

    SciTech Connect

    Grady, D.E.; Kipp, M.E.

    1993-07-01

    An investigation of the shock compression and release properties of silicon carbide ceramic has been performed. A series of planar impact experiments has been completed in which stationary target discs of ceramic were struck by plates of either similar ceramic or other appropriate material at velocities up to 2.2 km/s with a propellant gun facility. The particle velocity history at the interface between the back of the target ceramic and a lithium-fluoride window material was measured with laser velocity interferometry (VISAR). Impact stresses achieved in these experiments range between about 10 and 50 GPa. Numerical solutions and analytic methods were used to determine the dynamic compression and release stress-strain behavior of the ceramic. Further analysis of the data was performed to determine dynamic strength and compressibility properties of silicon carbide.

  3. Shock Compression of Liquid Helium to 56 GPa (560) Kbar

    NASA Technical Reports Server (NTRS)

    Nellis, W. J.; Holmes, N. C.; Mitchell, A. C.; Trainor, R. J.; Governo, G. K.; Ross, M.; Young, D. A.

    1985-01-01

    Shock-wave data are presented for liquid helium which has been compressed to densities up to five times greater than the normal liquid. The helium was heated to temperatures up to 21,000 K, while the maximum pressure attained was 56 GPa. The properties of helium and hydrogen are important for modeling the giant planets Saturn and Jupiter where these elements are the major constituents. Conditions on Saturn are of particular interest because studies have suggested that this planet has an internal energy source which is associated with unmixing and gravitational separation the hydrogen-helium fluid at pressures below 1 TPa. The existence of this phase transition depends very sensitively on the hydrogen and helium equation of state. In the experiments, strong shock waves were generated by the impact of planar projectiles into cryogenic specimen holders.

  4. Shock compression of liquid helium to 56 GPa (560 kbar)

    NASA Technical Reports Server (NTRS)

    Nellis, W. J.; Holmes, N. C.; Mitchell, A. C.; Governo, G. K.; Ross, M.; Young, D. A.; Trainor, R. J.

    1984-01-01

    Shock-wave data are presented for liquid helium which has been compressed to densities up to five times greater than the normal liquid. The helium was heated to temperatures up to 21,000 K, while the maximum pressure attained was 56 GPa. The properties of helium and hydrogen are important for modeling the giant planets Saturn and Jupiter where these elements are the major constituents. Conditions on Saturn are of particular interest because studies have suggested that this planet has an internal energy source which is associated with unmixing and gravitational separation of the hydrogen-helium fluid at pressures below 1 TPa. The existence of this phase transition depends very sensitively on the hydrogen and helium equation of state. In the experiments, strong shock waves were generated by the impact of planar projectiles into cryogenic specimen holders.

  5. What is a Shock Wave to an Explosive Molecule?

    SciTech Connect

    Tarver, C M

    2001-06-12

    An explosive molecule is a metastable chemical species that reacts exothermically given the correct stimulus. Impacting an explosive with a shock wave is a ''wake-up call'' or ''trigger'' which compresses and heats the molecule. The energy deposited by the shock wave must be distributed to the vibrational modes of the explosive molecule before chemical reaction can occur. If the shock pressure and temperature are high enough and last long enough, exothermic chemical decomposition can lead to the formation of a detonation wave. For gaseous, liquid, and perfect single crystal solid explosives, after an induction time, chemical reaction begins at or near the rear boundary of the charge. This induction time can be calculated by high pressure, high temperature transition state theory. A ''superdetonation'' wave travels through the preshocked explosive until it overtakes the initial shock wave and then slows to the steady state Chapman-Jouguet (C-J) velocity. In heterogeneous solid explosives, initiation of reaction occurs at ''hot spots'' created by shock compression. If there is a sufficient number of large and hot enough ''hot spots,'' these ignition sites grow creating a pressure pulse that overtakes the leading shock front causing detonation. Since the chemical energy is released well behind the leading shock front of a detonation wave, a mechanism is required for this energy to reinforce the leading shock front and maintain its overall constant velocity. This mechanism is the amplification of pressure wavelets in the reaction zone by the process of de-excitation of the initially highly vibrationally excited reaction product molecules. This process leads to the development of the three-dimensional structure of detonation waves observed for all explosives. In a detonation wave, the leading shock wave front becomes a ''burden'' for the explosive molecule to sustain by its chemical energy release.

  6. Vibrational spectroscopic investigations of shock-compressed liquid nitrogen and shock-compressed liquid nitromethane

    SciTech Connect

    Moore, D.S.; Schmidt, S.C.

    1989-01-01

    Vibrational spectra of liquid nitrogen and liquid nitromethane shock compressed to several high pressure/high temperature states were recorded using single-pulse multiplex coherent anti-Stokes Raman scattering. Vibrational frequencies were extracted from the data by computer spectral simulation techniques. Vibrational frequencies of liquid nitrogen were found to increase monotonically up to /approx/17.5 GPa single shock and /approx/30 GPa double shock and then to decrease with further increases in pressure. The consequence of the decrease in vibrational frequency on the Grueneisen mode gamma and its effect on the N/sub 2/ equation-of-state is discussed. A model is developed that includes the thermally-excited vibrational state transitions in the synthesized spectral fits of the nitromethane CARS data. The adequacy of the model for interpretation of CARS spectra in both ambient and shock-compressed nitromethane is discussed. 42 refs., 5 figs., 1 tab.

  7. Diagnostic of shock wave processes

    NASA Astrophysics Data System (ADS)

    Urtiew, P. A.

    1992-05-01

    Experimental measurements of high rate processes taking place in a shock wave dynamic environment require that the diagnostic systems have fast response and high resolution. This is not a trivial requirement considering the fact that under shock loading one can expect not only sudden changes of state across the shock discontinuity but also subsequent changes in pressure, temperature and volume due to chemical reaction, phase change and other transformations which may also take place behind the shock wave. Among the various parameters which provide direct ties to theoretical studies of the equation of state and at the same time yield to relatively accurate experimental measurements are shock velocity, particle velocity and pressure. Described here are the optical techniques VISAR and Fabry Perot interferometer for observing particle and free surface velocities in transparent media as well as in situ foil gauges for measuring pressure and particle velocity within the sample. Although these techniques are not new they have been continuously improved and upgraded at our facility to yield greater accuracy, reliability and state of the art performance. The emphasis in this paper is on the operational features of the measuring techniques, but examples of experimental results are also included.

  8. Millimeter-wave compressive holography.

    PubMed

    Cull, Christy Fernandez; Wikner, David A; Mait, Joseph N; Mattheiss, Michael; Brady, David J

    2010-07-01

    We describe an active millimeter-wave holographic imaging system that uses compressive measurements for three-dimensional (3D) tomographic object estimation. Our system records a two-dimensional (2D) digitized Gabor hologram by translating a single pixel incoherent receiver. Two approaches for compressive measurement are undertaken: nonlinear inversion of a 2D Gabor hologram for 3D object estimation and nonlinear inversion of a randomly subsampled Gabor hologram for 3D object estimation. The object estimation algorithm minimizes a convex quadratic problem using total variation (TV) regularization for 3D object estimation. We compare object reconstructions using linear backpropagation and TV minimization, and we present simulated and experimental reconstructions from both compressive measurement strategies. In contrast with backpropagation, which estimates the 3D electromagnetic field, TV minimization estimates the 3D object that produces the field. Despite undersampling, range resolution is consistent with the extent of the 3D object band volume.

  9. Model for Shock Wave Chaos

    NASA Astrophysics Data System (ADS)

    Kasimov, Aslan R.; Faria, Luiz M.; Rosales, Rodolfo R.

    2013-03-01

    We propose the following model equation, ut+1/2(u2-uus)x=f(x,us) that predicts chaotic shock waves, similar to those in detonations in chemically reacting mixtures. The equation is given on the half line, x<0, and the shock is located at x=0 for any t≥0. Here, us(t) is the shock state and the source term f is taken to mimic the chemical energy release in detonations. This equation retains the essential physics needed to reproduce many properties of detonations in gaseous reactive mixtures: steady traveling wave solutions, instability of such solutions, and the onset of chaos. Our model is the first (to our knowledge) to describe chaos in shock waves by a scalar first-order partial differential equation. The chaos arises in the equation thanks to an interplay between the nonlinearity of the inviscid Burgers equation and a novel forcing term that is nonlocal in nature and has deep physical roots in reactive Euler equations.

  10. The role of granular shocks in dust-layer dispersal by shock waves

    NASA Astrophysics Data System (ADS)

    Houim, Ryan; Ugarte, Orlando; Oran, Elaine

    2016-11-01

    Exactly how dust-layers are lifted and dispersed by shocks has been a longstanding question in compressible multiphase flow. Understanding the mechanism for this, however, is extremely important for early control of dust explosions. We address this problem by numerically solving a set of equations that couples a fully compressible representation of a gas with a kinetic-theory model for a granular medium (see) to simulate a shock propagating along the surface of a dust layer. The results show that the majority of the dispersed dust is lifted by hydrodynamic shear directly behind the shock wave. Simultaneously, large forces are produced behind the shock that compact the dust layer and create a granular shock. The effects from this granular shock on the surface of the dust layer destabilize the gas-dust boundary layer, which, in turn, enhances turbulence and the rate of dust dispersal.

  11. In-situ probing of lattice response in shock compressed materials using x-ray diffraction

    SciTech Connect

    Hawreliak, J; Butterfield, M; Davies, H; El-Dasher, B; Higginbotham, A; Kalantar, D; Kimminau, G; McNaney, J; Milathianaki, D; Murphy, W; Nagler, B; Lorenzana, H; Park, N; Remington, B; Thorton, L; Whitcher, T; Wark, J; Lorenzana, H

    2007-07-17

    Lattice level measurements of material response under extreme conditions are required to build a phenomenological understanding of the shock response of solids. We have successfully used laser produced plasma x-ray sources coincident with laser driven shock waves to make in-situ measurements of the lattice response during shock compression for both single crystal and polycrystalline materials. Using a detailed analysis of shocked single crystal iron which has undergone the {alpha} - {var_epsilon} phase transition we can constrain the transition mechanism to be consistent with a compression and shuffle of alternate lattice planes.

  12. IN-SITU PROBING OF LATTICE RESPONSE IN SHOCK COMPRESSED MATERIALS USING X-RAY DIFFRACTION

    SciTech Connect

    Hawreliak, James; Butterfield, Martin; El-Dasher, Bassem; Kalantar, Daniel; McNaney, James; Remington, Bruce; Lorenzana, Hector; Davies, Huw; Park, Nigel; Thorton, Lee; Higginbotham, Andrew; Kimminau, Giles; Murphy, William; Nagler, Bob; Whitcher, Thomas; Wark, Justin; Milathianaki, Despina

    2007-12-12

    Lattice level measurements of material response under extreme conditions are required to build a phenomenological understanding of the shock response of solids. We have successfully used laser produced plasma x-ray sources coincident with laser driven shock waves to make in-situ measurements of the lattice response during shock compression for both single crystal and polycrystalline materials. Using a detailed analysis of shocked single crystal iron which has undergone the {alpha}-{epsilon} phase transition we can constrain the transition mechanism to be consistent with a compression and shuffle of alternate lattice planes.

  13. Shock wave absorber having apertured plate

    DOEpatents

    Shin, Y.W.; Wiedermann, A.H.; Ockert, C.E.

    1983-08-26

    The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

  14. Shock wave absorber having apertured plate

    DOEpatents

    Shin, Yong W.; Wiedermann, Arne H.; Ockert, Carl E.

    1985-01-01

    The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

  15. Material response mechanisms are needed to obtain highly accurate experimental shock wave data

    NASA Astrophysics Data System (ADS)

    Forbes, Jerry W.

    2017-01-01

    The field of shock wave compression of matter has provided a simple set of equations relating thermodynamic and kinematic parameters that describe the conservation of mass, momentum and energy across a steady plane shock wave with one-dimensional flow. Well-known condensed matter shock wave experimental results will be reviewed to see whether the assumptions required for deriving these simple R-H equations are satisfied. Note that the material compression model is not required for deriving the 1-D conservation flow equations across a steady plane shock front. However, this statement is misleading from a practical experimental viewpoint since obtaining small systematic errors in shock wave measured parameters requires the material compression and release mechanisms to be known. A review will be presented on errors in shock wave data from common experimental techniques for elastic-plastic solids. Issues related to time scales of experiments, steady waves with long rise times and detonations will also be discussed

  16. Nonstandard Analysis and Jump Conditions for Converging Shock Waves

    NASA Technical Reports Server (NTRS)

    Baty, Roy S.; Farassat, Fereidoun; Tucker, Don H.

    2008-01-01

    Nonstandard analysis is an area of modern mathematics which studies abstract number systems containing both infinitesimal and infinite numbers. This article applies nonstandard analysis to derive jump conditions for one-dimensional, converging shock waves in a compressible, inviscid, perfect gas. It is assumed that the shock thickness occurs on an infinitesimal interval and the jump functions in the thermodynamic and fluid dynamic parameters occur smoothly across this interval. Predistributions of the Heaviside function and the Dirac delta measure are introduced to model the flow parameters across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the flow parameters.

  17. Nonstandard analysis and jump conditions for converging shock waves

    NASA Astrophysics Data System (ADS)

    Baty, Roy S.; Farassat, F.; Tucker, Don H.

    2008-06-01

    Nonstandard analysis is an area of modern mathematics that studies abstract number systems containing both infinitesimal and infinite numbers. This article applies nonstandard analysis to derive jump conditions for one-dimensional, converging shock waves in a compressible, inviscid, perfect gas. It is assumed that the shock thickness occurs on an infinitesimal interval and the jump functions in the thermodynamic and fluid dynamic parameters occur smoothly across this interval. Predistributions of the Heaviside function and the Dirac delta measure are introduced to model the flow parameters across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the flow parameters.

  18. Effects of shock structure on temperature field in compressible turbulence

    NASA Astrophysics Data System (ADS)

    Ni, Qionglin; Chen, Shiyi

    2014-11-01

    Effects of shock structure on temperature in compressible turbulence were investigated. The small-scale shocklets and large-scale shock waves were appeared in the flows driven by solenoidal and compressive forcings, i.e. SFT & CFT, respectively. In SFT the temperature had Kolmogorov spectrum and ramp-cliff structures, while in CFT it obeyed Burgers spectrum and was dominated by large-scale rarefaction and compression. The power-law exponents for the p.d.f. of large negative dilatation were -2.5 in SFT and -3.5 in CFT, approximately corresponded to model results. The isentropic approximation of thermodynamic variables showed that in SFT, the isentropic derivation was reinforced when turbulent Mach number increased. At similar turbulent Mach number, the variables in CFT exhibited more anisentropic. It showed that the transport of temperature was increased by the small-scale viscous dissipation and the large-scale pressure-dilatation. The distribution of positive and negative components of pressure-dilatation confirmed the mechanism of negligible pressure-dilatation at small scales. Further, the positive skewness of p.d.f.s of pressure-dilatation implied that the conversion from kinetic to internal energy by compression was more intense than the opposite process by rarefaction.

  19. Computation of Thermally Perfect Properties of Oblique Shock Waves

    NASA Technical Reports Server (NTRS)

    Tatum, Kenneth E.

    1996-01-01

    A set of compressible flow relations describing flow properties across oblique shock waves, derived for a thermally perfect, calorically imperfect gas, is applied within the existing thermally perfect gas (TPG) computer code. The relations are based upon a value of cp expressed as a polynomial function of temperature. The updated code produces tables of compressible flow properties of oblique shock waves, as well as the original properties of normal shock waves and basic isentropic flow, in a format similar to the tables for normal shock waves found in NACA Rep. 1135. The code results are validated in both the calorically perfect and the calorically imperfect, thermally perfect temperature regimes through comparisons with the theoretical methods of NACA Rep. 1135, and with a state-of-the-art computational fluid dynamics code. The advantages of the TPG code for oblique shock wave calculations, as well as for the properties of isentropic flow and normal shock waves, are its ease of use, and its applicability to any type of gas (monatomic, diatomic, triatomic, polyatomic, or any specified mixture thereof).

  20. Computation of Thermally Perfect Oblique Shock Wave Properties

    NASA Technical Reports Server (NTRS)

    Tatum, Kenneth E.

    1997-01-01

    A set of compressible flow relations describing flow properties across oblique shock waves, derived for a thermally perfect, calorically imperfect gas, is applied within the existing thermally perfect gas (TPG) computer code. The relations are based upon the specific heat expressed as a polynomial function of temperature. The updated code produces tables of compressible flow properties of oblique shock waves, as well as the original properties of normal shock waves and basic isentropic flow, in a format similar to the tables for normal shock waves found in NACA Rep. 1135. The code results are validated in both the calorically perfect and the calorically imperfect, thermally perfect temperature regimes through comparisons with the theoretical methods of NACA Rep. 1135. The advantages of the TPG code for oblique shock wave calculations, as well as for the properties of isentropic flow and normal shock waves, are its ease of use and its applicability to any type of gas (monatomic, diatomic, triatomic, polyatomic, or any specified mixture thereof).

  1. Shock wave consolidated MgB 2 bulk samples

    NASA Astrophysics Data System (ADS)

    Matsuzawa, Hidenori; Tamaki, Hideyuki; Ohashi, Wataru; Kakimoto, Etsuji; Dohke, Kiyotaka; Atou, Toshiyuki; Fukuoka, Kiyoto; Kikuchi, Masae; Kawasaki, Masashi; Takano, Yoshihiko

    2004-10-01

    Commercially available MgB 2 powders were consolidated into bulk samples by two different shock wave consolidation methods: underwater shock consolidation method and gun method. Resistance vs. temperature of the samples was measured by the four-terminal method for pulsed currents of up to 3 A in self-field, as well as Vickers hardness, SEM micrographs of fraction surfaces, packing densities, and X-ray diffraction patterns. These results, in comparison with cold isostatic pressed samples, indicated that the underwater shock consolidated sample was superior in grain connectivity to the others. This is probably because the underwater shock consolidation generated most anisotropic and hence high frictional, compressive, intergrain forces.

  2. Diagnoses of coaxial probes in shock compression.

    PubMed

    Sun, Yue; Ci, Jiaxiang; Yi, Pengfei; Zhang, Hongrun

    2009-06-01

    A miniature diagnostic apparatus, which consists of a target, a guiding tube, a nail-gun, and a simple base, has been developed in the proposed research to estimate batches of pinlike coaxial probes with selectable collision speeds, 198.3, 361.0, and 420.6 mps, corresponding to thrust capabilities of certain minibullets. This work aims at filling the gap between typical two stage light gas gun (>500 mps) and pendulum machine (<100 mps) with low cost and risk in realistic shock compressions. As a part of the experiment, the kappa coefficient and the statistical agreement and reliability are all evaluated.

  3. Diagnoses of coaxial probes in shock compression

    NASA Astrophysics Data System (ADS)

    Sun, Yue; Ci, Jiaxiang; Yi, Pengfei; Zhang, Hongrun

    2009-06-01

    A miniature diagnostic apparatus, which consists of a target, a guiding tube, a nail-gun, and a simple base, has been developed in the proposed research to estimate batches of pinlike coaxial probes with selectable collision speeds, 198.3, 361.0, and 420.6 mps, corresponding to thrust capabilities of certain minibullets. This work aims at filling the gap between typical two stage light gas gun (>500 mps) and pendulum machine (<100 mps) with low cost and risk in realistic shock compressions. As a part of the experiment, the κ coefficient and the statistical agreement and reliability are all evaluated.

  4. Bow shock and magnetosheath waves at Mercury

    NASA Technical Reports Server (NTRS)

    Fairfield, D. H.; Behannon, K. W.

    1975-01-01

    Mariner 10 measurements at the Mercury bow shock provide examples where the magnetic field is approximately parallel or perpendicular to the bow shock normal. Upstream of a broad irregular parallel shock, left hand circularly polarized waves are observed which cut off very sharply at approximately 4 Hz. Upstream of a perpendicular shock, right hand circularly polarized waves are observed which persist up to the Nyquist frequency of 12 Ha. Determination of the wave propagation vector as a function of frequency helps conclusively identify the waves as whistler mode waves propagating from the shock. The magnetosheath downstream of the parallel shock is disturbed more than that downstream of the perpendicular shock particularly below 1 Hz. In the latter case regular left hand polarized waves observed slightly above the proton gyrofrequency are identified as ion cyclotron waves with wavelength approximately 300 km which are Doppler shifted up to their observed frequency.

  5. Inelastic response of silicon to shock compression

    DOE PAGES

    Higginbotham, Andrew; Stubley, P. G.; Comley, A. J.; ...

    2016-04-13

    The elastic and inelastic response of [001] oriented silicon to laser compression has been a topic of considerable discussion for well over a decade, yet there has been little progress in understanding the basic behaviour of this apparently simple material. We present experimental x-ray diffraction data showing complex elastic strain profiles in laser compressed samples on nanosecond timescales. We also present molecular dynamics and elasticity code modelling which suggests that a pressure induced phase transition is the cause of the previously reported ‘anomalous’ elastic waves. Moreover, this interpretation allows for measurement of the kinetic timescales for transition. Lastly, this modelmore » is also discussed in the wider context of reported deformation of silicon to rapid compression in the literature.« less

  6. Inelastic response of silicon to shock compression

    SciTech Connect

    Higginbotham, Andrew; Stubley, P. G.; Comley, A. J.; Eggert, J. H.; Foster, J. M.; Kalantar, D. H.; McGonegle, D.; Patel, S.; Peacock, L. J.; Rothman, S. D.; Smith, R. F.; Suggit, M. J.; Wark, J. S.

    2016-04-13

    The elastic and inelastic response of [001] oriented silicon to laser compression has been a topic of considerable discussion for well over a decade, yet there has been little progress in understanding the basic behaviour of this apparently simple material. We present experimental x-ray diffraction data showing complex elastic strain profiles in laser compressed samples on nanosecond timescales. We also present molecular dynamics and elasticity code modelling which suggests that a pressure induced phase transition is the cause of the previously reported ‘anomalous’ elastic waves. Moreover, this interpretation allows for measurement of the kinetic timescales for transition. Lastly, this model is also discussed in the wider context of reported deformation of silicon to rapid compression in the literature.

  7. Inelastic response of silicon to shock compression

    PubMed Central

    Higginbotham, A.; Stubley, P. G.; Comley, A. J.; Eggert, J. H.; Foster, J. M.; Kalantar, D. H.; McGonegle, D.; Patel, S.; Peacock, L. J.; Rothman, S. D.; Smith, R. F.; Suggit, M. J.; Wark, J. S.

    2016-01-01

    The elastic and inelastic response of [001] oriented silicon to laser compression has been a topic of considerable discussion for well over a decade, yet there has been little progress in understanding the basic behaviour of this apparently simple material. We present experimental x-ray diffraction data showing complex elastic strain profiles in laser compressed samples on nanosecond timescales. We also present molecular dynamics and elasticity code modelling which suggests that a pressure induced phase transition is the cause of the previously reported ‘anomalous’ elastic waves. Moreover, this interpretation allows for measurement of the kinetic timescales for transition. This model is also discussed in the wider context of reported deformation of silicon to rapid compression in the literature. PMID:27071341

  8. Vorticity and Wave Motion in a Compressible Protoplanetary Disk

    NASA Technical Reports Server (NTRS)

    Davis, Sanford S.; DeVincenzi, Donald (Technical Monitor)

    2001-01-01

    The impact of an isolated vortex in a compressible Keplerian disk is examined using higher order numerical solutions of the Euler and entropy-conserving Energy equations. The vortex is stretched by the background shear flow with longer lasting anticyclonic vortices persisting for about 10 vortex revolutions. Simultaneously, the vortex emits transient radial waves consisting mainly of axisymmetrical weak shock waves and a slower, nonaxisymmetric Rossby wave. These waves may contribute to certain transient events in protoplanetary disks. The vortex stretching and waves were found to have little long-term feedback on the baseline 'standard solar nebula' disk structure and confirm the extremely stable structure of non self-gravitating disks.

  9. Burnett-Cattaneo continuum theory for shock waves

    NASA Astrophysics Data System (ADS)

    Holian, Brad Lee; Mareschal, Michel; Ravelo, Ramon

    2011-02-01

    We model strong shock-wave propagation, both in the ideal gas and in the dense Lennard-Jones fluid, using a refinement of earlier work, which accounts for the cold compression in the early stages of the shock rise by a nonlinear, Burnett-like, strain-rate dependence of the thermal conductivity, and relaxation of kinetic-temperature components on the hot, compressed side of the shock front. The relaxation of the disequilibrium among the three components of the kinetic temperature, namely, the difference between the component in the direction of a planar shock wave and those in the transverse directions, particularly in the region near the shock front, is accomplished at a much more quantitative level by a rigorous application of the Cattaneo-Maxwell relaxation equation to a reference solution, namely, the steady shock-wave solution of linear Navier-Stokes-Fourier theory, along with the nonlinear Burnett heat-flux term. Our new continuum theory is in nearly quantitative agreement with nonequilibrium molecular-dynamics simulations under strong shock-wave conditions, using relaxation parameters obtained from the reference solution.

  10. Insulator to semiconductor transformation of planetary ice mixtures compressed by laser-driven shock wave and its implication for interior properties of icy giant planets

    NASA Astrophysics Data System (ADS)

    Okuchi, T.; Ozaki, N.; Sano, T.; Sakawa, Y.; Kodama, R.

    2016-12-01

    Molecular ices in the universe are consisting of hydrogen, oxygen, carbon, and nitrogen. Such ices containing these elements coalesced to develop into icy giant planets such as Uranus, Neptune, as well as those in some extrasolar planetary systems. Properties of such planetary ices at elevated pressures and temperatures are essential clues for understanding the layering structures and material circulations inside these icy giant planets. In particular, strong magnetic fields are generated in the deep interiors of these planets by thermal convection, so that the planetary ices are expected to be electrically conductive at the relevant pressure and temperature conditions.Here by using high-power nanosecond laser pulses from GEKKO-XII neodymium-doped glass laser system installed at the Institute of Laser Engineering, Osaka University, four distinct chemical types of planetary ices are shock-compressed, and initial appearance and subsequent increase of free electron careers within each chemical type are experimentally observed. The chemical types include (i) H2O, (ii) H2O + carbon, (iii) H2O + nitrogen, and (iv) H2O + carbon + nitrogen. Their hydrogen/oxygen to carbon and hydrogen/oxygen to nitrogen molar ratios reflect that of the cosmic ice, so that our type (iv) corresponds to "synthetic Uranus" used by Nellis and coworkers. The measured conditions include pressures between 50 GPa to 190 GPa and temperatures between 3000 K and 14000 K, which were simultaneously determined with density and optical reflectivity at 532 nm of the solutions using picosecond time-resolved optical diagnostics for shock-compressed state of the materials. A common occurrence of insulator to electronic semiconductor transition was observed for all the chemical types, while the transition pressure conditions are substantially different among these types. Carbon-bearing ices consistently show lower transition pressure and temperature, indicating that electronically semiconducting states inside

  11. The History of the APS Shock Compression of Condensed Matter Topical Group

    SciTech Connect

    Forbes, J W

    2001-05-02

    In order to provide broader scientific recognition and to advance the science of shock compressed condensed matter, a group of American Physical Society (APS) members worked within the Society to make this field an active part of the APS. Individual papers were presented at APS meetings starting in the 1940's and shock wave sessions were organized starting with the 1967 Pasadena meeting. Shock wave topical conferences began in 1979 in Pullman, WA. Signatures were obtained on a petition in 1984 from a balanced cross-section of the shock wave community to form an APS Topical Group (TG). The APS Council officially accepted the formation of the Shock Compression of Condensed Matter (SCCM) TG at its October 1984 meeting. This action firmly aligned the shock wave field with a major physical science organization. Most early topical conferences were sanctioned by the APS while those held after 1992 were official APS meetings. The topical group organizes a shock wave topical conference in odd numbered years while participating in shock wave/high pressure sessions at APS general meetings in even numbered years.

  12. The History of the APS Topical Group on Shock Compression of Condensed Matter

    NASA Astrophysics Data System (ADS)

    Forbes, Jerry W.

    2002-07-01

    In order to provide broader scientific recognition and to advance the science of shock compressed condensed matter, a group of American Physical Society (APS) members worked within the Society to make this field an active part of the APS. Individual papers were presented at APS meetings starting in the 1940's and shock wave sessions were organized starting with the 1967 Pasadena meeting. Shock wave topical conferences began in 1979 in Pullman, WA. Signatures were obtained on a petition in 1984 from a balanced cross-section of the shock wave community to form an APS Topical Group (TG). The APS Council officially accepted the formation of the Shock Compression of Condensed Matter (SCCM) TG at its October 1984 meeting. This action firmly aligned the shock wave field with a major physical science organization. Most early topical conferences were sanctioned by the APS while those held after 1992 were official APS meetings. The topical group organizes a shock wave topical conference in odd numbered years while participating in shock wave/high pressure sessions at APS general meetings in even numbered years.

  13. Multi-Scale Shock Compression Simulations of Metals and Metallic Phase Transitions

    NASA Astrophysics Data System (ADS)

    Goldman, Nir; Fried, Larry

    2011-03-01

    We present a straightforward method for efficient molecular dynamics (MD) simulation of shock compression of materials that experience thermal electronic excitations at high pressure and temperature. Previous studies have shown that exclusion of the electronic temperature at extreme conditions can result in incorrect computation of dynamic and equation of state properties. The Multi-Scale Shock Technique (MSST) is a simulation methodology based on the Navier--Stokes equations for compressible flow that enables MD simulation of a shock wave with relatively small computational cost. We extend MSST to allow for changes in the electronic entropy during shock compression while conserving Hugoniot conditions. This allows for simulation of significantly higher shock velocities than previously possibly with MSST. We have used our simulation methodology in density functional tight binding simulations of shock compressed silicon. We observe that at high shock velocities inclusion of a non-zero electron temperature results in lower computed shock Hugoniot temperatures and pressures. Our methodology is well suited for shock compression simulations of any material that experiences changes in its electronic entropy under extreme thermodynamic conditions. Prepared by LLNL under Contract DE-AC52-07NA27344.

  14. Compressed Sensing Meets Wave Chaology

    NASA Astrophysics Data System (ADS)

    Pinto, Innocenzo M.; Addesso, Paolo; Principe, Maria

    2015-03-01

    The Wigner distribution is an important tool in the study of high-frequency wave-packet dynamics in ray-chaotic enclosures. Smoothing the Wigner distribution helps improving its readability, by suppressing nonlinear artifacts, but spoils its resolution. Adding a sparsity constraint to smoothing, in the spirit of the compressed coding paradigm, restores resolution while still avoiding artifacts. The result is particularly valuable in the perspective of complexity gauging via Renyi-Wehrl entropy measures. Representative numerical experiments are presented to substantiate such clues.

  15. Detonation onset following shock wave focusing

    NASA Astrophysics Data System (ADS)

    Smirnov, N. N.; Penyazkov, O. G.; Sevrouk, K. L.; Nikitin, V. F.; Stamov, L. I.; Tyurenkova, V. V.

    2017-06-01

    The aim of the present paper is to study detonation initiation due to focusing of a shock wave reflected inside a cone. Both numerical and experimental investigations were conducted. Comparison of results made it possible to validate the developed 3-d transient mathematical model of chemically reacting gas mixture flows incorporating hydrogen - air mixtures. The results of theoretical and numerical experiments made it possible improving kinetic schemes and turbulence models. Several different flow scenarios were detected in reflection of shock waves all being dependent on incident shock wave intensity: reflecting of shock wave with lagging behind combustion zone, formation of detonation wave in reflection and focusing, and intermediate transient regimes.

  16. Experimental study of highly compressed iron user laser driven shocks

    NASA Astrophysics Data System (ADS)

    Benuzzi-Mounaix, Alessandra; Huser, Gael; Koenig, Michel; Grandjouan, Nicolas; Faral, Bernard; Batani, Dimitri; Henry, Emeric; Tomasini, Michaela; Hall, Thomas; Romain, Jp; Resseguier, Thibault; Hallouin, Martine; Guyot, François

    2001-06-01

    Experiments with lasers have recently provided important improvements in our knowledge of highly compressed matter (in particular, Equation Of State). We present recent results on iron which are relevant to planetary physics1. We measured the free surface velocity of the compressed iron by using a VISAR diagnostic2, and the shock velocity through step targets on the same shot3. An absolute EOS is then deduced for the lower pressures (1-3 Mbar). For higher pressures (3-7 Mbar), we compared release wave in vacuum with calculassions based on SESAME EOS . With a iron+LiF window, we also determined a release wave in iron for the transmitted shock in the window. The experiments have been performed at the LULI laboratory of the Ecole Polytechnique. References 1 W. Anderson, et al., J. Geophys. Research 99, 4273 (1994). 2 P. M. Celliers, et al., Applied Phys. Lett. 73, 1320 (1998). 3 M. Koenig, et al., Phys. Rev. Lett. 74, 2260 (1995).

  17. History of the APS Topical Group on Shock Compression of Condensed Matter

    SciTech Connect

    Forbes, J W

    2001-10-19

    In order to provide broader scientific recognition and to advance the science of shock compressed condensed matter, a group of American Physical Society (APS) members worked within the Society to make this field an active part of the APS. Individual papers were presented at APS meetings starting in the 1940's and shock wave sessions were organized starting with the 1967 Pasadena meeting. Shock wave topical conferences began in 1979 in Pullman, WA. Signatures were obtained on a petition in 1984 from a balanced cross-section of the shock wave community to form an APS Topical Group (TG). The APS Council officially accepted the formation of the Shock Compression of Condensed Matter (SCCM) TG at its October 1984 meeting. This action firmly aligned the shock wave field with a major physical science organization. Most early topical conferences were sanctioned by the APS while those held after 1992 were official APS meetings. The topical group organizes a shock wave topical conference in odd numbered years while participating in shock wavehigh pressure sessions at APS general meetings in even numbered years.

  18. Analgesia for shock wave lithotripsy.

    PubMed

    Parkin, John; Keeley FX, Francis X; Timoney, Anthony G

    2002-04-01

    We evaluated the effectiveness of and patient preference for analgesia used during shock wave lithotripsy by comparing diclofenac alone with a combination of diclofenac and patient controlled analgesia, that is alfentanil. A total of 64 patients were treated using a Lithotriptor S (Dornier Medical Systems, Marietta, Georgia) and randomized to receive diclofenac alone or combined with an alfentanil patient controlled analgesia pump. If treated twice, they crossed over to the alternative form of analgesia. A record was maintained of the site and size of the stone, maximum power achieved, number of shocks, amount of alfentanil used and need for additional analgesia. After treatment patients scored on a visual analog scale the maximum level of pain and satisfaction with analgesia. There was no difference in the mean size of the stone treated (8.6 and 7.5 mm.), energy level (71% and 71% or approximately 17 kV.) or number of shocks (3,000 and 2,900, respectively) in the groups. Only 2 patients in the diclofenac group required additional analgesia and there were no significant side effects from either treatment. The mean pain scores were not significantly different in the diclofenac and patient controlled analgesia groups (3.54 and 2.93, respectively, (p = 0.34), although those on patient controlled analgesia were more satisfied (7.72 versus 9.14, p = 0.04). Of the 38 patients who presented twice 58% preferred diclofenac alone. This study suggests that there is no significant difference in the level of pain experienced with diclofenac alone or when combined with an alfentanil patient controlled analgesia pump during shock wave lithotripsy. However, patients are more satisfied with treatment when a patient controlled analgesia pump is available.

  19. Shock compression response of forsterite above 250 GPa.

    PubMed

    Sekine, Toshimori; Ozaki, Norimasa; Miyanishi, Kohei; Asaumi, Yuto; Kimura, Tomoaki; Albertazzi, Bruno; Sato, Yuya; Sakawa, Youichi; Sano, Takayoshi; Sugita, Seiji; Matsui, Takafumi; Kodama, Ryosuke

    2016-08-01

    Forsterite (Mg2SiO4) is one of the major planetary materials, and its behavior under extreme conditions is important to understand the interior structure of large planets, such as super-Earths, and large-scale planetary impact events. Previous shock compression measurements of forsterite indicate that it may melt below 200 GPa, but these measurements did not go beyond 200 GPa. We report the shock response of forsterite above ~250 GPa, obtained using the laser shock wave technique. We simultaneously measured the Hugoniot and temperature of shocked forsterite and interpreted the results to suggest the following: (i) incongruent crystallization of MgO at 271 to 285 GPa, (ii) phase transition of MgO at 285 to 344 GPa, and (iii) remelting above ~470 to 500 GPa. These exothermic and endothermic reactions are seen to occur under extreme conditions of pressure and temperature. They indicate complex structural and chemical changes in the system MgO-SiO2 at extreme pressures and temperatures and will affect the way we understand the interior processes of large rocky planets as well as material transformation by impacts in the formation of planetary systems.

  20. Shock compression response of forsterite above 250 GPa

    PubMed Central

    Sekine, Toshimori; Ozaki, Norimasa; Miyanishi, Kohei; Asaumi, Yuto; Kimura, Tomoaki; Albertazzi, Bruno; Sato, Yuya; Sakawa, Youichi; Sano, Takayoshi; Sugita, Seiji; Matsui, Takafumi; Kodama, Ryosuke

    2016-01-01

    Forsterite (Mg2SiO4) is one of the major planetary materials, and its behavior under extreme conditions is important to understand the interior structure of large planets, such as super-Earths, and large-scale planetary impact events. Previous shock compression measurements of forsterite indicate that it may melt below 200 GPa, but these measurements did not go beyond 200 GPa. We report the shock response of forsterite above ~250 GPa, obtained using the laser shock wave technique. We simultaneously measured the Hugoniot and temperature of shocked forsterite and interpreted the results to suggest the following: (i) incongruent crystallization of MgO at 271 to 285 GPa, (ii) phase transition of MgO at 285 to 344 GPa, and (iii) remelting above ~470 to 500 GPa. These exothermic and endothermic reactions are seen to occur under extreme conditions of pressure and temperature. They indicate complex structural and chemical changes in the system MgO-SiO2 at extreme pressures and temperatures and will affect the way we understand the interior processes of large rocky planets as well as material transformation by impacts in the formation of planetary systems. PMID:27493993

  1. Interplanetary shock waves associated with solar flares

    NASA Technical Reports Server (NTRS)

    Chao, J. K.; Sakurai, K.

    1974-01-01

    The interaction of the earth's magnetic field with the solar wind is discussed with emphasis on the influence of solar flares. The geomagnetic storms are considerered to be the result of the arrival of shock wave generated by solar flares in interplanetary space. Basic processes in the solar atmosphere and interplanetary space, and hydromagnetic disturbances associated with the solar flares are discussed along with observational and theoretical problems of interplanetary shock waves. The origin of interplanetary shock waves is also discussed.

  2. Observation of traveling thermoacoustic shock waves (L).

    PubMed

    Biwa, Tetsushi; Takahashi, Takuma; Yazaki, Taichi

    2011-12-01

    Shock waves were explored in the thermoacoustic spontaneous gas oscillations occurring in a gas column with a steep temperature gradient. The results show that a periodic shock occurs in the traveling wave mode in a looped tube but not in the standing wave mode in a resonator. Measurements of the harmonic components of the acoustic intensity reveal a clear difference between them. The temperature gradient acts as an acoustic energy source for the harmonic components of the shock wave in the traveling wave mode but as an acoustic energy sink of the second harmonic in the standing wave mode. © 2011 Acoustical Society of America

  3. Vibrational spectroscopy in shock-compressed liquids

    SciTech Connect

    Schmidt, S.C.; Moore, D.S.

    1992-01-01

    Coherent anti-Stokes Raman spectroscopy is being used to study the structure and energy transfer in simple molecular liquids at the high pressures and temperatures characteristic of explosive detonation. Dense fluids to several thousand degrees temperature and several hundred kilobars pressure are obtained using the shock-compression technique. Vibrational frequencies, third-order susceptibility ratios, and linewidths have been measured for N{sub 2}, O{sub 2}, CO, mixtures of N{sub 2}, O{sub 2}, and CO, and N{sub 2}O. Frequencies are found to increase with pressure. The transition intensity and line-width data suggest that thermal equilibrium of the vibrational levels is attained in less than a few nanoseconds at these high pressures and temperatures. Vibrational temperatures obtained are compared to those derived from equation-of-state calculations.

  4. Vibrational spectroscopy in shock-compressed liquids

    SciTech Connect

    Schmidt, S.C.; Moore, D.S.

    1992-03-01

    Coherent anti-Stokes Raman spectroscopy is being used to study the structure and energy transfer in simple molecular liquids at the high pressures and temperatures characteristic of explosive detonation. Dense fluids to several thousand degrees temperature and several hundred kilobars pressure are obtained using the shock-compression technique. Vibrational frequencies, third-order susceptibility ratios, and linewidths have been measured for N{sub 2}, O{sub 2}, CO, mixtures of N{sub 2}, O{sub 2}, and CO, and N{sub 2}O. Frequencies are found to increase with pressure. The transition intensity and line-width data suggest that thermal equilibrium of the vibrational levels is attained in less than a few nanoseconds at these high pressures and temperatures. Vibrational temperatures obtained are compared to those derived from equation-of-state calculations.

  5. IN SITU ELLIPSOMETRY FOR SHOCK COMPRESSION MEASUREMENTS

    SciTech Connect

    Bakshi, L.; Eliezer, S.; Appelbaum, G.; Nissim, N.; Perelmutter, L.; Mond, M.

    2009-12-28

    Knowledge about the optical properties of materials at high pressure and high temperature is needed for EOS research. Ellipsometry measures the change in the polarization of a probe beam reflected from a surface. From the change in polarization, the real and imaginary parts of the time dependent complex index of refraction can be extracted. From the measured optical properties, fundamental physical properties of the material, such as emissivity, phase transitions, and electrical conductivity can be extracted. A dynamic ellipsometry measurement system with nanosecond resolution was built in order to measure all four stocks parameters. Gas gun was used to accelerate the impact flyer. Our experiments concentrated on the optical properties of 1020 steel targets with impact pressure range of 40-250 kbar. Although there are intrinsic difficulties with dynamic ellipsometric measurements, distinct changes were observed for 1020 steel under shock compression larger than 130 kbar, the alpha->epsilon phase transition.

  6. A computer program for the calculation of the flow field in supersonic mixed-compression inlets at angle of attack using the three-dimensional method of characteristics with discrete shock wave fitting

    NASA Technical Reports Server (NTRS)

    Vadyak, J.; Hoffman, J. D.; Bishop, A. R.

    1978-01-01

    The calculation procedure is based on the method of characteristics for steady three-dimensional flow. The bow shock wave and the internal shock wave system were computed using a discrete shock wave fitting procedure. The general structure of the computer program is discussed, and a brief description of each subroutine is given. All program input parameters are defined, and a brief discussion on interpretation of the output is provided. A number of sample cases, complete with data deck listings, are presented.

  7. Studies of Shock Wave Interactions with Homogeneous and Isotropic Turbulence

    NASA Technical Reports Server (NTRS)

    Briassulis, G.; Agui, J.; Watkins, C. B.; Andreopoulos, Y.

    1998-01-01

    A nearly homogeneous nearly isotropic compressible turbulent flow interacting with a normal shock wave has been studied experimentally in a large shock tube facility. Spatial resolution of the order of 8 Kolmogorov viscous length scales was achieved in the measurements of turbulence. A variety of turbulence generating grids provide a wide range of turbulence scales. Integral length scales were found to substantially decrease through the interaction with the shock wave in all investigated cases with flow Mach numbers ranging from 0.3 to 0.7 and shock Mach numbers from 1.2 to 1.6. The outcome of the interaction depends strongly on the state of compressibility of the incoming turbulence. The length scales in the lateral direction are amplified at small Mach numbers and attenuated at large Mach numbers. Even at large Mach numbers amplification of lateral length scales has been observed in the case of fine grids. In addition to the interaction with the shock the present work has documented substantial compressibility effects in the incoming homogeneous and isotropic turbulent flow. The decay of Mach number fluctuations was found to follow a power law similar to that describing the decay of incompressible isotropic turbulence. It was found that the decay coefficient and the decay exponent decrease with increasing Mach number while the virtual origin increases with increasing Mach number. A mechanism possibly responsible for these effects appears to be the inherently low growth rate of compressible shear layers emanating from the cylindrical rods of the grid.

  8. Converging shock wave focusing and interaction with a target

    SciTech Connect

    Nitishinskiy, M.; Efimov, S.; Antonov, O.; Yanuka, D.; Gurovich, V. Tz.; Krasik, Ya. E.; Bernshtam, V.; Fisher, V.

    2016-04-15

    Converging shock waves in liquids can be used efficiently in the research of the extreme state of matter and in various applications. In this paper, the recent results related to the interaction of a shock wave with plasma preliminarily formed in the vicinity of the shock wave convergence are presented. The shock wave is produced by the underwater electrical explosion of a spherical wire array. The plasma is generated prior to the shock wave's arrival by a low-pressure gas discharge inside a quartz capillary placed at the equatorial plane of the array. Analysis of the Stark broadening of H{sub α} and H{sub β} spectral lines and line-to-continuum ratio, combined with the ratio of the relative intensities of carbon C III/C II and silicon Si III/Si II lines, were used to determine the plasma density and temperature evolution. It was found that during the first ∼200 ns with respect to the beginning of the plasma compression by the shock wave and when the spectral lines are resolved, the plasma density increases from 2 × 10{sup 17 }cm{sup −3} to 5 × 10{sup 17 }cm{sup −3}, while the temperature remains at the same value of 3–4 eV. Further, following the model of an adiabatically imploding capillary, the plasma density increases >10{sup 19 }cm{sup −3}, leading to the continuum spectra obtained experimentally, and the plasma temperature >30 eV at radii of compression of ≤20 μm. The data obtained indicate that the shock wave generated by the underwater electrical explosion of a spherical wire array retains its uniformity during the main part of its convergence.

  9. Study on miss distance based on projectile shock wave sensor

    NASA Astrophysics Data System (ADS)

    Gu, Guohua; Cheng, Gang; Zhang, Chenjun; Zhou, Lei

    2017-05-01

    The paper establishes miss distance models based on physical characteristic of shock-wave. The aerodynamic theory shows that the shock-wave of flying super-sonic projectile is generated for the projectile compressing and expending its ambient atmosphere. It advances getting miss distance according to interval of the first sensors, which first catches shock-wave, to solve the problem such as noise filtering on severe background, and signals of amplifier vibration dynamic disposal and electromagnetism compatibility, in order to improves the precision and reliability of gathering wave N signals. For the first time, it can identify the kinds of pills and firing units automatically, measure miss distance and azimuth when pills are firing. Application shows that the tactics and technique index is advanced all of the world.

  10. Cavitation in shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Bailey, Michael R.; Crum, Lawrence A.; Sapozhnikov, Oleg A.; Evan, Andrew P.; McAteer, James A.; Colonius, Tim; Cleveland, Robin O.

    2003-10-01

    A case is presented for the important role of cavitation in stone comminution and tissue injury in shock wave lithotripsy (SWL). Confocal hydrophones and a coincidence algorithm were used to detect cavitation in kidney parenchyma. Elevated hydrostatic pressure dissolved cavitation nuclei and suppressed cell injury and stone comminution in vitro. A low-insertion-loss, thin, mylar film nearly eliminated stone erosion and crack formation only when in direct contact with the stone. This result indicates not only that cavitation is important in both cracking and erosion but also that bubbles act at the surface. Time inversion of the shock wave by use of a pressure-release reflector reduced the calculated pressure at bubble collapse and the measured depth of bubble-induced pits in aluminum. Correspondingly tissue injury in vivo was nearly eliminated. Cavitation was localized and intensified by the use of synchronously triggered, facing lithotripters. This dual pulse lithotripter enhanced comminution at its focus and reduced lysis in surrounding blood samples. The enhancement of comminution was lost when stones were placed in glycerol, which retarded bubble implosion. Thus, cavitation is important in comminution and injury and can be controlled to optimize efficacy and safety. [Work supported by NIH DK43381, DK55674, and FIRCA.

  11. Shock Wave Technology and Application: An Update☆

    PubMed Central

    Rassweiler, Jens J.; Knoll, Thomas; Köhrmann, Kai-Uwe; McAteer, James A.; Lingeman, James E.; Cleveland, Robin O.; Bailey, Michael R.; Chaussy, Christian

    2012-01-01

    Context The introduction of new lithotripters has increased problems associated with shock wave application. Recent studies concerning mechanisms of stone disintegration, shock wave focusing, coupling, and application have appeared that may address some of these problems. Objective To present a consensus with respect to the physics and techniques used by urologists, physicists, and representatives of European lithotripter companies. Evidence acquisition We reviewed recent literature (PubMed, Embase, Medline) that focused on the physics of shock waves, theories of stone disintegration, and studies on optimising shock wave application. In addition, we used relevant information from a consensus meeting of the German Society of Shock Wave Lithotripsy. Evidence synthesis Besides established mechanisms describing initial fragmentation (tear and shear forces, spallation, cavitation, quasi-static squeezing), the model of dynamic squeezing offers new insight in stone comminution. Manufacturers have modified sources to either enlarge the focal zone or offer different focal sizes. The efficacy of extracorporeal shock wave lithotripsy (ESWL) can be increased by lowering the pulse rate to 60–80 shock waves/min and by ramping the shock wave energy. With the water cushion, the quality of coupling has become a critical factor that depends on the amount, viscosity, and temperature of the gel. Fluoroscopy time can be reduced by automated localisation or the use of optical and acoustic tracking systems. There is a trend towards larger focal zones and lower shock wave pressures. Conclusions New theories for stone disintegration favour the use of shock wave sources with larger focal zones. Use of slower pulse rates, ramping strategies, and adequate coupling of the shock wave head can significantly increase the efficacy and safety of ESWL. PMID:21354696

  12. Shock wave technology and application: an update.

    PubMed

    Rassweiler, Jens J; Knoll, Thomas; Köhrmann, Kai-Uwe; McAteer, James A; Lingeman, James E; Cleveland, Robin O; Bailey, Michael R; Chaussy, Christian

    2011-05-01

    The introduction of new lithotripters has increased problems associated with shock wave application. Recent studies concerning mechanisms of stone disintegration, shock wave focusing, coupling, and application have appeared that may address some of these problems. To present a consensus with respect to the physics and techniques used by urologists, physicists, and representatives of European lithotripter companies. We reviewed recent literature (PubMed, Embase, Medline) that focused on the physics of shock waves, theories of stone disintegration, and studies on optimising shock wave application. In addition, we used relevant information from a consensus meeting of the German Society of Shock Wave Lithotripsy. Besides established mechanisms describing initial fragmentation (tear and shear forces, spallation, cavitation, quasi-static squeezing), the model of dynamic squeezing offers new insight in stone comminution. Manufacturers have modified sources to either enlarge the focal zone or offer different focal sizes. The efficacy of extracorporeal shock wave lithotripsy (ESWL) can be increased by lowering the pulse rate to 60-80 shock waves/min and by ramping the shock wave energy. With the water cushion, the quality of coupling has become a critical factor that depends on the amount, viscosity, and temperature of the gel. Fluoroscopy time can be reduced by automated localisation or the use of optical and acoustic tracking systems. There is a trend towards larger focal zones and lower shock wave pressures. New theories for stone disintegration favour the use of shock wave sources with larger focal zones. Use of slower pulse rates, ramping strategies, and adequate coupling of the shock wave head can significantly increase the efficacy and safety of ESWL. Copyright © 2011 European Association of Urology. Published by Elsevier B.V. All rights reserved.

  13. Regions and Transitions of Nonstationary Oblique Shock-Wave Diffractions in Perfect and Imperfect Gases.

    DTIC Science & Technology

    1978-08-01

    The diffraction of shock waves (2 or = M sub s or = 8) in perfect and imperfect nitrogen and argon by sharp compressive corners (2 deg or = Theta...in argon in the ranges 1 or = M subs or = 10 and 0 deg or = Theta sub w or = 90 deg. The domains consist of the four well-known shock wave

  14. Biological Effects of Shock Waves on Infection

    NASA Astrophysics Data System (ADS)

    Gnanadhas, Divya Prakash; Janardhanraj, S.; Chakravortty, Dipshikha; Gopalan, Jagadeesh

    Shock waves have been successfully used for disintegrating kidney stones[1], noninvasive angiogenic approach[2] and for the treatment of osteoporosis[3]. Recently shock waves have been used to treat different medical conditions including intestinal anastomosis[4], wound healing[5], Kienböck's disease[6] and articular cartilage defects[7].

  15. Shock wave therapy in wound healing.

    PubMed

    Qureshi, Ali A; Ross, Kimberly M; Ogawa, Rei; Orgill, Dennis P

    2011-12-01

    Recently, shock wave therapy has been investigated as an adjuvant therapy in the treatment of acute and chronic wounds. There are several devices with focused and unfocused shock waves that have been administered to a heterogenous group of wounds. Encouraging preclinical and clinical studies suggest that shock wave therapy may promote wound healing with little or no adverse events, prompting investigations into the mechanism of action and additional clinical trials. The peer-reviewed literature within the past 10 years was studied using an evidence-based approach. Preclinical studies demonstrate that shock wave therapy affects cellular function and leads to the expression of several genes and elaboration of growth factors known to promote wound healing. Limited clinical trials are encouraging for the use of shock wave therapy in the treatment of acute and chronic wounds. Serious complications, including wound infections, bleeding, hematomas, seromas, and petechiae, have not been reported in the largest of these studies. Shock wave therapy is an intriguing physical modality that may play an important role as an adjuvant therapy in wound healing. To date, there is no consensus on which wounds are most likely to benefit from shock wave therapy and what the optimal power, degree of focus, and frequency or number of cycles should be. Well-designed preclinical and clinical studies are necessary to better understand shock wave therapy in wound healing.

  16. Numerical simulation of converging shock waves

    NASA Astrophysics Data System (ADS)

    Yee, Seokjune; Abe, Kanji

    We can achieve the high pressure and high temperature state of gas if the shock wave converges stably. In order to check the stability of the converging shock wave, we introduce two kinds of perturbed initial conditions. The Euler equations of conservation form are integrated by using explicit Non-Muscl TVD finite difference scheme.

  17. Molecular dynamics simulation of the plastic behavior anisotropy of shock-compressed monocrystal nickel

    NASA Astrophysics Data System (ADS)

    Chen, Ya-Zhou; Zhou, Liu-Cheng; He, Wei-Feng; Sun, Yu; Li, Ying-Hong; Jiao, Yang; Luo, Si-Hai

    2017-01-01

    Molecular dynamics simulations were used to study the plastic behavior of monocrystalline nickel under shock compression along the [100] and [110] orientations. The shock Hugoniot relation, local stress curve, and process of microstructure development were determined. Results showed the apparent anisotropic behavior of monocrystalline nickel under shock compression. The separation of elastic and plastic waves was also obvious. Plastic deformation was more severely altered along the [110] direction than the [100] direction. The main microstructure phase transformed from face-centered cubic to body-centered cubic and generated a large-scale and low-density stacking fault along the family of { 111 } crystal planes under shock compression along the [100] direction. By contrast, the main mechanism of plastic deformation in the [110] direction was the nucleation of the hexagonal, close-packed phase, which generated a high density of stacking faults along the [110] and [1̅10] directions.

  18. Evolution Of Nonlinear Waves in Compressing Plasma

    SciTech Connect

    P.F. Schmit, I.Y. Dodin, and N.J. Fisch

    2011-05-27

    Through particle-in-cell simulations, the evolution of nonlinear plasma waves is examined in one-dimensional collisionless plasma undergoing mechanical compression. Unlike linear waves, whose wavelength decreases proportionally to the system length L(t), nonlinear waves, such as solitary electron holes, conserve their characteristic size {Delta} during slow compression. This leads to a substantially stronger adiabatic amplification as well as rapid collisionless damping when L approaches {Delta}. On the other hand, cessation of compression halts the wave evolution, yielding a stable mode.

  19. Thermophysical properties of multi-shock compressed dense argon

    SciTech Connect

    Chen, Q. F. Zheng, J.; Gu, Y. J.; Chen, Y. L.; Cai, L. C.; Shen, Z. J.

    2014-02-21

    In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ∼6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models.

  20. Shock Waves in Inert and Reactive Media

    NASA Astrophysics Data System (ADS)

    Fomin, N. A.

    2017-05-01

    "Shock waves are of special interest from a whole number of aspects. On the one hand, where attempts at integrating equations without introducing discontinuities (i.e., shock waves) lead to these or those paradoxes and to the impossibility of solving these equations, the shock wave theory resolves paradoxes and permits creating regimes of motion under any conditions. One the other hand, shock waves themselves are a paradoxical event. They are paradoxical in the sense that without making any assumptions about dissipative forces — about viscosity and heat conduction — we obtain, from elementary considerations, laws, according to which there is an increase in entropy, i.e., laws, according to which the processes proceeding in the shock wave are irreversible."

  1. Raman spectroscopy of hypersonic shock waves

    PubMed

    Ramos; Mate; Tejeda; Fernandez; Montero

    2000-10-01

    Raman spectroscopy is shown to be an efficient diagnostic methodology for the study of hypersonic shock waves. As a test, absolute density and rotational population profiles have been measured across five representative normal shock waves of N2 generated in a free jet, spanning the Mach number range 7.7shock waves shows a largely bimodal rotational distribution function with additional contribution of scattered molecules, in close analogy with the velocity distribution function known from helium shock waves [G. Pham-Van-Diep et al., Science 245, 624 (1989)]. Quantitative data on invariance trends of density profiles and properties of the wake beyond the shock waves are reported.

  2. Reflection of curved shock waves

    NASA Astrophysics Data System (ADS)

    Mölder, S.

    2017-09-01

    Shock curvatures are related to pressure gradients, streamline curvatures and vorticity in flows with planar and axial symmetry. Explicit expressions, in an influence coefficient format, are used to relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. Using higher order, von Neumann-type, compatibility conditions, curved shock theory is applied to calculate the flow near singly and doubly curved shocks on curved surfaces, in regular shock reflection and in Mach reflection. Theoretical curved shock shapes are in good agreement with computational fluid dynamics calculations and experiment.

  3. Reflection of curved shock waves

    NASA Astrophysics Data System (ADS)

    Mölder, S.

    2017-03-01

    Shock curvatures are related to pressure gradients, streamline curvatures and vorticity in flows with planar and axial symmetry. Explicit expressions, in an influence coefficient format, are used to relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. Using higher order, von Neumann-type, compatibility conditions, curved shock theory is applied to calculate the flow near singly and doubly curved shocks on curved surfaces, in regular shock reflection and in Mach reflection. Theoretical curved shock shapes are in good agreement with computational fluid dynamics calculations and experiment.

  4. Feasibility of stimulated emission to measure {ital R}-line shifts in shock compressed ruby

    SciTech Connect

    Knudson, M.D.; Gupta, Y.M.

    1999-05-01

    In previous studies, ruby {ital R}-line shifts under shock compression and tension have been measured using the spontaneous luminescence from optically pumped samples. The signal intensities obtained are limited by the short time duration of the experiments in comparison to the long lifetime of the luminescence. We have investigated the use of stimulated emission for measuring {ital R}-line shifts in shocked ruby crystals. Experiments were performed both at ambient conditions and under shock compression to 6 GPa using an experimental configuration similar to that used for time resolved ruby luminescence measurements in previous shock wave studies. Signal gain due to stimulated emission was observed, with gains ranging from 1.1 to 3.4, in agreement with calculations performed for the particular experimental configuration used. The present results make a good case for incorporating this technique into the measurement of shock induced {ital R}-line shifts in ruby. {copyright} {ital 1999 American Institute of Physics.}

  5. International Shock-Wave Database: Systematization of Experimental Data

    NASA Astrophysics Data System (ADS)

    Levashov, Pavel R.; Khishchenko, Konstantin V.; Lomonosov, Igor V.; Minakov, Dmitry V.; Zakharenkov, Alexey S.

    2011-06-01

    In this work, we announce the creation of the International Shock-Wave Database (ISWDB). Shock-wave and related dynamic material response data serve for calibrating, validating, and improving material models over very broad regions of the pressure-temperature-density phase space. Our objectives are (i) to develop a database on thermodynamic and mechanical properties of materials under conditions of shock wave and other dynamic loadings, selected related quantities of interest, and the meta-data that describes the provenance of the measurements and material models, and (ii) to make this database available internationally thru the Internet, in an interactive form. The development and operation of the ISWDB will be guided by input from a steering committee. The database will be installed on two mirrored web-servers, one in Russia and the other in USA. The database will provide access to original experimental data on shock compression, non-shock dynamic loadings, isentropic expansion, measurements of sound speed in the Hugoniot state, and time-dependent free-surface or window-interface velocity profiles. We believe that the ISWDB will be a useful tool for the shock-wave community.

  6. Shock compression response of a Zr-based bulk metallic glass up to 110 GPa

    NASA Astrophysics Data System (ADS)

    Xi, Feng; Yu, Yuying; Dai, Chengda; Zhang, Yi; Cai, Lingcang

    2010-10-01

    Shock wave compression experiments were conducted on a Zr-based bulk metallic glass (BMG, Zr51Ti5Ni10Cu25Al9 in atomic percent) up to 110 GPa. Time-resolved free-surface velocity profiles were measured in a shock stress range from 18 to 28 GPa with velocity interferometer techniques. The shock Hugoniot data in a shock stress range from 53 to 110 GPa were obtained by using electric pin techniques. The time-resolved wave profiles showed a distinct two-wave structure consisting of an elastic precursor followed by a plastic wave. Based on the obtained wave profiles, the Hugoniot elastic limits were determined to be 6.9 to 9.6 GPa. The shock wave velocity (Ds) vs. particle velocity (up) Hugoniot data in a shock stress range from 18 to 110 GPa were linearly fitted by Ds=(4.241±0.035)+(1.015±0.024)up. No evidence of phase transition was found in the performed shock experiments of the Zr-based BMG.

  7. Shock Wave Dynamics in Weakly Ionized Plasmas

    NASA Technical Reports Server (NTRS)

    Johnson, Joseph A., III

    1999-01-01

    An investigation of the dynamics of shock waves in weakly ionized argon plasmas has been performed using a pressure ruptured shock tube. The velocity of the shock is observed to increase when the shock traverses the plasma. The observed increases cannot be accounted for by thermal effects alone. Possible mechanisms that could explain the anomalous behavior include a vibrational/translational relaxation in the nonequilibrium plasma, electron diffusion across the shock front resulting from high electron mobility, and the propagation of ion-acoustic waves generated at the shock front. Using a turbulence model based on reduced kinetic theory, analysis of the observed results suggest a role for turbulence in anomalous shock dynamics in weakly ionized media and plasma-induced hypersonic drag reduction.

  8. Optical carrier wave shocking: detection and dispersion.

    PubMed

    Kinsler, P; Radnor, S B P; Tyrrell, J C A; New, G H C

    2007-06-01

    Carrier wave shocking is studied using the pseudospectral spatial-domain (PSSD) technique. We describe the shock detection diagnostics necessary for this numerical study and verify them against theoretical shocking predictions for the dispersionless case. These predictions show a carrier envelope phase and pulse bandwidth sensitivity in the single-cycle regime. The flexible dispersion management offered by the PSSD enables us to independently control the linear and nonlinear dispersion. Customized dispersion profiles allow us to analyze the development of both carrier self-steepening and shocks. The results exhibit a marked asymmetry between normal and anomalous dispersion, both in the limits of the shocking regime and in the (near) shocked pulse wave forms. Combining these insights, we offer some suggestions on how carrier shocking (or at least extreme self-steepening) might be realized experimentally.

  9. Development of microcapsules for shock wave DDS and angiogenesis using shock waves

    NASA Astrophysics Data System (ADS)

    Tamagawa, M.; Yamanoi, I.; Iwakura, S.

    2006-05-01

    This paper describes the trial of making microcapsules including a bubble for shock wave drug delivery systems, evaluation of their mechanical properties and angiogenesis using plane shock waves. We have proposed drug delivery systems (DDS) using shock waves. In this system, a microcapsule including a gas bubble is flown in the blood vessel, and finally broken by shock induced microjet, then drug is reached to the affected part. In this paper, the mechanism for deformation and disintegration of capsules in our previous works is reviewed, and the trials of making special microcapsules are discussed. To determine Young's modulus of capsule membrane, the membrane is deformed by the aspiration device and compared with computational result by FEM. As for angiogenesis using shock wave, the effects of shock waves under 0.4 MPa on cell growth rate is investigated. It is found that increasing rate of cell population by working shock waves is faster than the control cells.

  10. Shock wave application to cell cultures.

    PubMed

    Holfeld, Johannes; Tepeköylü, Can; Kozaryn, Radoslaw; Mathes, Wolfgang; Grimm, Michael; Paulus, Patrick

    2014-04-08

    Shock waves nowadays are well known for their regenerative effects. Basic research findings showed that shock waves do cause a biological stimulus to target cells or tissue without any subsequent damage. Therefore, in vitro experiments are of increasing interest. Various methods of applying shock waves onto cell cultures have been described. In general, all existing models focus on how to best apply shock waves onto cells. However, this question remains: What happens to the waves after passing the cell culture? The difference of the acoustic impedance of the cell culture medium and the ambient air is that high, that more than 99% of shock waves get reflected! We therefore developed a model that mainly consists of a Plexiglas built container that allows the waves to propagate in water after passing the cell culture. This avoids cavitation effects as well as reflection of the waves that would otherwise disturb upcoming ones. With this model we are able to mimic in vivo conditions and thereby gain more and more knowledge about how the physical stimulus of shock waves gets translated into a biological cell signal ("mechanotransduction").

  11. Shock wave equation of state of muscovite

    NASA Technical Reports Server (NTRS)

    Sekine, Toshimori; Rubin, Allan M.; Ahrens, Thomas J.

    1991-01-01

    Shock wave data were obtained between 20 and 140 GPa for natural muscovite obtained from Methuen Township (Ontario), in order to provide a shock-wave equation of state for this crustal hydrous mineral. The shock equation of state data could be fit by a linear shock velocity (Us) versus particle velocity (Up) relation Us = 4.62 + 1.27 Up (km/s). Third-order Birch-Murnaghan equation of state parameters were found to be K(OS) = 52 +/-4 GPa and K-prime(OS) = 3.2 +/-0.3 GPa. These parameters are comparable to those of other hydrous minerals such as brucite, serpentine, and tremolite.

  12. Shock wave equation of state of muscovite

    NASA Technical Reports Server (NTRS)

    Sekine, Toshimori; Rubin, Allan M.; Ahrens, Thomas J.

    1991-01-01

    Shock wave data were obtained between 20 and 140 GPa for natural muscovite obtained from Methuen Township (Ontario), in order to provide a shock-wave equation of state for this crustal hydrous mineral. The shock equation of state data could be fit by a linear shock velocity (Us) versus particle velocity (Up) relation Us = 4.62 + 1.27 Up (km/s). Third-order Birch-Murnaghan equation of state parameters were found to be K(OS) = 52 +/-4 GPa and K-prime(OS) = 3.2 +/-0.3 GPa. These parameters are comparable to those of other hydrous minerals such as brucite, serpentine, and tremolite.

  13. Overview of shock waves in medicine

    NASA Astrophysics Data System (ADS)

    Cleveland, Robin O.

    2003-10-01

    A brief overview of three applications of shock waves is presented. Shock wave lithotripsy (SWL) has been in clinical use for more than 20 years. In the United States it is used to treat more than 80% of kidney stone cases and has wide acceptance with patients because it is a noninvasive procedure. Despite SWLs enormous success there is no agreement on how shock waves comminute stones. There is also a general acceptance that shock waves lead to trauma to the soft tissue of the kidney. Yet there has been little forward progress in developing lithotripters which provide comminution with less side-effects, indeed the original machine is still considered the gold standard. The last decade has seen the advent of new shock wave devices for treating principally musculoskeletal indications, such as plantar fasciitis, tennis elbow, and bone fractures that do not heal. This is referred to as shock wave therapy (SWT). The mechanisms by which SWT works are even less well understood than SWL and the consequences of bioeffects have also not been studied in detail. Shock waves have also been shown to be effective at enhancing drug delivery into cells and assisting with gene transfection. [Work partially supported by NIH.

  14. Database for properties of materials studied in experiments using shock waves

    NASA Astrophysics Data System (ADS)

    Zhernokletov, M. V.; Trunin, R. F.; Gudarenko, L. F.; Trushchin, V. D.; Gushchina, O. N.

    1997-07-01

    During nearly 50-year period of development of the dynamic methods for studying material properties Russia accumulated a large amount of experimental data for more than 200 individual materials, compounds, condensed media and gases. Practically all the information is obtained at RFNC-VNIIEF. For the accumulated experimental data systematization and visualization the database being presented was developed. At its development DBMS Paradox for Windows was used. The database is a set of interconnected tables storing: the data for shock compression of continuous materials; the data for shock compression of heated materials; the data for shock compression of porous materials; the data for shock compression of materials by the second shock wave; expansion adiabats of shock-compressed continuous materials; expansion adiabats of shock-compressed porous materials; the data for the rate of scattering of shock-compressed materials to air; the data for sound speed in shock-compressed materials. Currently the database stores the data for the following material types: metals; metal hydrides and nitrides; carbides and oxides; mixtures; solid organic materials; alkali metal halogenides; minerals and rocks; water and saturated water solutions of salts; organic liquids. As the data is (and will be) transferred to the Experimental data base from a great number of various sources (papers and reports), it also stores the complete list of these sources.

  15. Dense particle cloud dispersion by a shock wave

    NASA Astrophysics Data System (ADS)

    Kellenberger, Mark Douglas

    High-speed particle dispersion research is motivated by the energy release enhancement of explosives containing solid particles. In the initial explosive dispersal, a dense gas-solid flow can exist where the physics of phase interactions are not well understood. A dense particle flow is generated by the interaction of a shock wave with an initially stationary packed granular bed. The initial packed granular bed is produced by compressing loose aluminum oxide powder into a 6.35 mm thick wafer with a particle volume fraction of 0.48. The wafer is positioned inside the shock tube, uniformly filling the entire cross-section. This results in a clean experiment where no flow obstructing support structures are present. Through high-speed shadowgraph imaging and pressure measurements along the length of the channel, detailed information about the particle-shock interaction was obtained. Due to the limited strength of the Mach 2 incident shock wave, no transmitted shock wave is produced. The initial "solid-like" response of the particle wafer acceleration forms a series of compression waves that coalesce to form a shock wave. Breakup is initiated along the periphery of the wafer as the result of shear that forms due to the fixed boundary condition. Particle break-up starts at local failure sites that result in the formation of particle jets that extend ahead of the accelerating, largely intact, wafer core. In a circular tube the failure sites are uniformly distributed along the wafer circumference. In a square channel, the failure sites, and the subsequent particle jets, initially form at the corners due to the enhanced shear. The wafer breakup subsequently spreads to the edges forming a highly non-uniform particle cloud.

  16. Measurement of Sound Velocities in Shock-Compressed Tin Under Pressures up to 150 GPa

    NASA Astrophysics Data System (ADS)

    Zhernokletov, M. V.; Kovalev, A. E.; Komissarov, V. V.; Zocher, M. A.; Cherne, F. J.

    2009-12-01

    Sound velocity in shock-compressed tin was measured over the pressure range of 31-138 GPa by the overtake method with using indicator liquids. Photodiode-based optical gauges were used to record luminescence of the liquid indicators. For shock compressions of 5-18 GPa, the sound velocity in tin was measured with manganin gauges by determining the oncoming release wave in the tin. The experimental data were compared to calculated results and data obtained by other authors. According to data obtained in this work, tin melts on the hugoniot between ˜63-90 GPa.

  17. Elimination of cavitation-related attenuation in shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Sankin, G. N.; Lautz, J. M.; Simmons, W. N.; Zhong, P.; Frank, S. T.; Szeri, A. J.

    2017-03-01

    In shock wave lithotripsy (SWL), acoustic pulses with a leading compression wave followed by a tensile wave are delivered into the patient's body using a water-filled coupling cushion. Cavitation-related acoustic energy loss in the coupling unit depends critically on water conditions, e.g. dissolved gas concentration and exchange flow rate. We have systematically investigated the attenuation mechanism in the coupling water via pressure measurements and cavitation characterization. In non-degassed water the bubble cluster became progressively dense (i.e., proliferated because of gas diffusion into bubbles and splitting of bubbles into many daughter bubbles) in shock waves delivered at 1 Hz leading to reduction in the tensile wave duration from a nominal value of 4.6 to 1.8 µs. To reduce cavitation in the coupling water along the beam path, we have used a continuous jet flow to remove residual daughter bubbles between consecutive shocks. As a result, stone fragmentation efficiency was increased from 16±4% to 30±5% (p = 0.002) after 250 shocks. Such a hydrodynamic approach for tensile wave attenuation in the coupling water may be used to provide a flexible means for a novel treatment strategy with tissue protection.

  18. Shock Wave Profiles in Glass Reinforced Polyester

    NASA Astrophysics Data System (ADS)

    Boteler, J. Michael; Rajendran, A. M.; Grove, David

    1999-06-01

    The promise of lightweight armor which is also structurally robust is of particular importance to the Army for future combat vehicles. Fiber reinforced organic matrix composites such as Glass Reinforced Polyester (GRP) are being considered for this purpose due to their lower density and promising dynamic response. The work discussed here extends the prior work of Boteler who studied the delamination strength of GRP and Dandekar and Beaulieu who investigated the compressive and tensile strengths of GRP. In a series of shock wave experiments, the wave profile was examined as a function of propagation distance in GRP. Uniaxial strain was achieved by plate impact in the ARL 102 mm bore single-stage light gas gun. Embedded polyvinylidene flouride (PVDF) stress-rate gauges provided a stress history at three unique locations in the GRP and particle velocity history was recorded with VISAR. The use of Lagrange gauges embedded in such a manner provides a means of calculating the constitutive relationships between specific volume, stress, and particle velocity uniquely with no prior assumptions of the form of constitutive relation. The Lagrangian analysis will be discussed and compared to Lagrangian hydrocode (EPIC) results employing a model to describe the viscoelastic response of the composite material in one-dimension.

  19. Shock wave profiles in polymer matrix composite

    NASA Astrophysics Data System (ADS)

    Boteler, J. Michael; Rajendran, A. M.; Grove, David

    2000-04-01

    The promise of lightweight armor which is also structurally robust is of particular importance to the Army for future combat vehicles. Fiber reinforced organic matrix composites such as Polymer Matrix Composite (PMC) are being considered for this purpose due to their lower density and promising dynamic response. The work discussed here extends the prior work of Boteler who studied the delamination strength of PMC and Dandekar and Beaulieu who investigated the compressive and tensile strengths of PMC. In a series of shock wave experiments, the wave profile was examined as a function of propagation distance in PMC. Uniaxial strain was achieved by symmetric plate impact in the ARL 102 mm bore single-stage light gas gun. Embedded polyvinylidene flouride (PVDF) stress-rate gauges provided a stress history at three unique locations in the PMC and particle velocity history was recorded with VISAR. All stress data was compared to a Lagrangian hydrocode (EPIC) employing a model to describe the viscoelastic response of the composite material in one-dimension. The experimental stress histories displayed attenuation and loading properties in good agreement with model predictions. However, the unloading was observed to be markedly different than the hydrocode simulations. These results are discussed.

  20. Limitations of extracorporeal shock wave lithotripsy.

    PubMed

    Madaan, Sanjeev; Joyce, Adrian D

    2007-03-01

    Extracorporeal shock wave lithotripsy (ESWL) is the preferred modality for the treatment of renal and upper ureteric calculi. The present review focuses on the limitations of ESWL, where recent developments have tried to identify patients who are unlikely to succeed with ESWL and where improvements in shock wave delivery may increase successful stone fragmentation. Evaluation of patients prior to ESWL is especially important, and the use of imaging in the decision process, with the use of computed tomography attenuation values and skin-to-stone distance, can help improve our ability to identify suitable patients for shock wave treatment. Continued research into the methods of shock wave delivery techniques and lithotripter designs will help achieve better stone fragmentation rates with reduced side effects. The importance of traditional factors in predicting ESWL success, such as stone size, location, composition and renal anatomy, are well known. More recently, authors have created nomograms to predict stone-free outcome after ESWL. Others have used the information obtained from computed tomography to predict stone comminution. In addition, modifications in shock wave delivery by altering shock rate and voltage have been researched in an effort to improve shock wave efficacy.

  1. Shock waves in strongly coupled plasmas

    SciTech Connect

    Khlebnikov, Sergei; Kruczenski, Martin; Michalogiorgakis, Georgios

    2010-12-15

    Shock waves are supersonic disturbances propagating in a fluid and giving rise to dissipation and drag. Weak shocks, i.e., those of small amplitude, can be well described within the hydrodynamic approximation. On the other hand, strong shocks are discontinuous within hydrodynamics and therefore probe the microscopics of the theory. In this paper, we consider the case of the strongly coupled N=4 plasma whose microscopic description, applicable for scales smaller than the inverse temperature, is given in terms of gravity in an asymptotically AdS{sub 5} space. In the gravity approximation, weak and strong shocks should be described by smooth metrics with no discontinuities. For weak shocks, we find the dual metric in a derivative expansion, and for strong shocks we use linearized gravity to find the exponential tail that determines the width of the shock. In particular, we find that, when the velocity of the fluid relative to the shock approaches the speed of light v{yields}1 the penetration depth l scales as l{approx}(1-v{sup 2}){sup 1/4}. We compare the results with second-order hydrodynamics and the Israel-Stewart approximation. Although they all agree in the hydrodynamic regime of weak shocks, we show that there is not even qualitative agreement for strong shocks. For the gravity side, the existence of shock waves implies that there are disturbances of constant shape propagating on the horizon of the dual black holes.

  2. Stability of shock waves in high temperature plasmas

    SciTech Connect

    Das, Madhusmita; Bhattacharya, Chandrani; Menon, S. V. G.

    2011-10-15

    The Dyakov-Kontorovich criteria for spontaneous emission of acoustic waves behind shock fronts are investigated for high temperature aluminum and beryllium plasmas. To this end, the Dyakov and critical stability parameters are calculated from Rankine-Hugoniot curves using a more realistic equation of state (EOS). The cold and ionic contributions to the EOS are obtained via scaled binding energy and mean field theory, respectively. A screened hydrogenic model, including l-splitting, is used to calculate the bound electron contribution to the electronic EOS. The free electron EOS is obtained from Fermi-Dirac statistics. Predictions of the model for ionization curves and shock Hugoniot are found to be in excellent agreement with available experimental and theoretical data. It is observed that the electronic EOS has significant effect on the stability of the planar shock front. While the shock is stable for low temperatures and pressures, instability sets in as temperature rises. The basic reason is ionization of electronic shells and consequent increase in electronic specific heat. The temperatures and densities of the unstable region correspond to those where electronic shells get ionized. With the correct modeling of bound electrons, we find that shock instability for Al occurs at a compression ratio {approx}5.4, contrary to the value {approx}3 reported in the literature. Free electrons generated in the ionization process carry energy from the shock front, thereby giving rise to spontaneously emitted waves, which decay the shock front.

  3. Computation of shock wave/target interaction

    NASA Technical Reports Server (NTRS)

    Mark, A.; Kutler, P.

    1983-01-01

    Computational results of shock waves impinging on targets and the ensuing diffraction flowfield are presented. A number of two-dimensional cases are computed with finite difference techniques. The classical case of a shock wave/cylinder interaction is compared with shock tube data and shows the quality of the computations on a pressure-time plot. Similar results are obtained for a shock wave/rectangular body interaction. Here resolution becomes important and the use of grid clustering techniques tend to show good agreement with experimental data. Computational results are also compared with pressure data resulting from shock impingement experiments for a complicated truck-like geometry. Here of significance are the grid generation and clustering techniques used. For these very complicated bodies, grids are generated by numerically solving a set of elliptic partial differential equations.

  4. Turbulence modeling in shock wave/turbulent boundary layer interactions

    NASA Technical Reports Server (NTRS)

    Smits, A. J.

    1992-01-01

    The research performed was an experimental program to help develop turbulence models for shock wave boundary layer interactions. The measurements were taken in a Mach 3, 16 deg compression corner interaction, at a unit Reynolds number of 63 x 10(exp 6)/m. The data consisted of heat transfer data taken upstream and downstream of the interaction, hot wire measurements of the instantaneous temperature and velocity fluctuations to verify the Strong Reynolds Analogy, and single- and double-pulsed Rayleigh scattering images to study the development of the instantaneous shock/turbulence interaction.

  5. The microphysics of collisionless shock waves.

    PubMed

    Marcowith, A; Bret, A; Bykov, A; Dieckman, M E; Drury, L O'C; Lembège, B; Lemoine, M; Morlino, G; Murphy, G; Pelletier, G; Plotnikov, I; Reville, B; Riquelme, M; Sironi, L; Novo, A Stockem

    2016-04-01

    Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks, supernova remnants, pulsar winds and their nebulæ, active galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or acceleration. It turns out that the shock phenomenon is a multi-scale non-linear problem in time and space. It is complexified by the impact due to high-energy cosmic rays in astrophysical environments. This review adresses the physics of shock formation, shock dynamics and particle acceleration based on a close examination of available multi-wavelength or in situ observations, analytical and numerical developments. A particular emphasis is made on the different instabilities triggered during the shock formation and in association with particle acceleration processes with regards to the properties of the background upstream medium. It appears that among the most important parameters the background magnetic field through the magnetization and its obliquity is the dominant one. The shock velocity that can reach relativistic speeds has also a strong impact over the development of the micro-instabilities and the fate of particle acceleration. Recent developments of laboratory shock experiments has started to bring some new insights in the physics of space plasma and astrophysical shock waves. A special section is dedicated to new laser plasma experiments probing shock physics.

  6. Thermal transport in shock wave–compressed solids using pulsed laser heating

    SciTech Connect

    La Lone, B. M.; Capelle, G.; Stevens, G. D.; Turley, W. D.; Veeser, L. R.

    2014-07-01

    A pulsed laser heating method was developed for determining thermal transport properties of solids under shock-wave compression. While the solid is compressed, a laser deposits a known amount of heat onto the sample surface, which is held in the shocked state by a transparent window. The heat from the laser briefly elevates the surface temperature and then diffuses into the interior via one-dimensional heat conduction. The thermal effusivity is determined from the time history of the resulting surface temperature pulse, which is recorded with optical pyrometry. Thermal effusivity is the square root of the product of thermal conductivity and volumetric heat capacity and is the key thermal transport parameter for relating the surface temperature to the interior temperature of the sample in a dynamic compression experiment. Therefore, this method provides information that is needed to determine the thermodynamic state of the interior of a compressed metal sample from a temperature measurement at the surface. The laser heat method was successfully demonstrated on tin that was shock compressed with explosives to a stress and temperature of ~25 GPa and ~1300 K. In this state, tin was observed to have a thermal effusivity of close to twice its ambient value. The implications on determining the interior shock wave temperature of tin are discussed.

  7. Thermal transport in shock wave–compressed solids using pulsed laser heating

    SciTech Connect

    La Lone, B. M. Capelle, G.; Stevens, G. D.; Turley, W. D.; Veeser, L. R.

    2014-07-15

    A pulsed laser heating method was developed for determining thermal transport properties of solids under shock-wave compression. While the solid is compressed, a laser deposits a known amount of heat onto the sample surface, which is held in the shocked state by a transparent window. The heat from the laser briefly elevates the surface temperature and then diffuses into the interior via one-dimensional heat conduction. The thermal effusivity is determined from the time history of the resulting surface temperature pulse, which is recorded with optical pyrometry. Thermal effusivity is the square root of the product of thermal conductivity and volumetric heat capacity and is the key thermal transport parameter for relating the surface temperature to the interior temperature of the sample in a dynamic compression experiment. Therefore, this method provides information that is needed to determine the thermodynamic state of the interior of a compressed metal sample from a temperature measurement at the surface. The laser heat method was successfully demonstrated on tin that was shock compressed with explosives to a stress and temperature of ∼25 GPa and ∼1300 K. In this state, tin was observed to have a thermal effusivity of close to twice its ambient value. The implications on determining the interior shock wave temperature of tin are discussed.

  8. Shock waves on complex networks

    PubMed Central

    Mones, Enys; Araújo, Nuno A. M.; Vicsek, Tamás; Herrmann, Hans J.

    2014-01-01

    Power grids, road maps, and river streams are examples of infrastructural networks which are highly vulnerable to external perturbations. An abrupt local change of load (voltage, traffic density, or water level) might propagate in a cascading way and affect a significant fraction of the network. Almost discontinuous perturbations can be modeled by shock waves which can eventually interfere constructively and endanger the normal functionality of the infrastructure. We study their dynamics by solving the Burgers equation under random perturbations on several real and artificial directed graphs. Even for graphs with a narrow distribution of node properties (e.g., degree or betweenness), a steady state is reached exhibiting a heterogeneous load distribution, having a difference of one order of magnitude between the highest and average loads. Unexpectedly we find for the European power grid and for finite Watts-Strogatz networks a broad pronounced bimodal distribution for the loads. To identify the most vulnerable nodes, we introduce the concept of node-basin size, a purely topological property which we show to be strongly correlated to the average load of a node. PMID:24821422

  9. Lagrangian averaging, nonlinear waves, and shock regularization

    NASA Astrophysics Data System (ADS)

    Bhat, Harish S.

    In this thesis, we explore various models for the flow of a compressible fluid as well as model equations for shock formation, one of the main features of compressible fluid flows. We begin by reviewing the variational structure of compressible fluid mechanics. We derive the barotropic compressible Euler equations from a variational principle in both material and spatial frames. Writing the resulting equations of motion requires certain Lie-algebraic calculations that we carry out in detail for expository purposes. Next, we extend the derivation of the Lagrangian averaged Euler (LAE-alpha) equations to the case of barotropic compressible flows. The derivation in this thesis involves averaging over a tube of trajectories etaepsilon centered around a given Lagrangian flow eta. With this tube framework, the LAE-alpha equations are derived by following a simple procedure: start with a given action, expand via Taylor series in terms of small-scale fluid fluctuations xi, truncate, average, and then model those terms that are nonlinear functions of xi. We then analyze a one-dimensional subcase of the general models derived above. We prove the existence of a large family of traveling wave solutions. Computing the dispersion relation for this model, we find it is nonlinear, implying that the equation is dispersive. We carry out numerical experiments that show that the model possesses smooth, bounded solutions that display interesting pattern formation. Finally, we examine a Hamiltonian partial differential equation (PDE) that regularizes the inviscid Burgers equation without the addition of standard viscosity. Here alpha is a small parameter that controls a nonlinear smoothing term that we have added to the inviscid Burgers equation. We show the existence of a large family of traveling front solutions. We analyze the initial-value problem and prove well-posedness for a certain class of initial data. We prove that in the zero-alpha limit, without any standard viscosity

  10. Photoacoustic shock wave emission and cavitation from structured optical fiber tips

    SciTech Connect

    Mohammadzadeh, M.; Gonzalez-Avila, S. R.; Ohl, C. D.; Wan, Y. C.; Wang, X.; Zheng, H.

    2016-01-11

    Photoacoustic waves generated at the tip of an optical fiber consist of a compressive shock wave followed by tensile diffraction waves. These tensile waves overlap along the fiber axis and form a cloud of cavitation bubbles. We demonstrate that shaping the fiber tip through micromachining alters the number and direction of the emitted waves and cavitation clouds. Shock wave emission and cavitation patterns from five distinctively shaped fiber tips have been studied experimentally and compared to a linear wave propagation model. In particular, multiple shock wave emission and generation of strong tension away from the fiber axis have been realized using modified fiber tips. These altered waveforms may be applied for novel microsurgery protocols, such as fiber-based histotripsy, by utilizing bubble-shock wave interaction.

  11. Dynamic Shock Compression of Copper to Multi-Megabar Pressure

    NASA Astrophysics Data System (ADS)

    Haill, T. A.; Furnish, M. D.; Twyeffort, L. L.; Arrington, C. L.; Lemke, R. W.; Knudson, M. D.; Davis, J.-P.

    2015-11-01

    Copper is an important material for a variety of shock and high energy density applications and experiments. Copper is used as a standard reference material to determine the EOS properties of other materials. The high conductivity of copper makes it useful as an MHD driver layer in high current dynamic materials experiments on Sandia National Laboratories Z machine. Composite aluminum/copper flyer plates increase the dwell time in plate impact experiments by taking advantage of the slower wave speeds in copper. This presentation reports on recent efforts to reinstate a composite Al/Cu flyer capability on Z and to extend the range of equation-of-state shock compression data through the use of hyper-velocity composite flyers and symmetric planar impact with copper targets. We will present results from multi-dimensional ALEGRA MHD simulations, as well as experimental designs and methods of composite flyer fabrication. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. DOE's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  12. Origin of compression-induced failure in brittle solids under shock loading

    NASA Astrophysics Data System (ADS)

    Huang, J. Y.; Li, Y.; Liu, Q. C.; Zhou, X. M.; Liu, L. W.; Liu, C. L.; Zhu, M. H.; Luo, S. N.

    2015-10-01

    The origin of compression-induced failure in brittle solids has been a subject of debate. Using in situ, high-speed, strain field mapping of a representative material, polymethylmethacrylate, we reveal that shock loading leads to heterogeneity in a compressive strain field, which in turn gives rise to localized lateral tension and shear through Poisson's effects, and, subsequently, localized microdamage. A failure wave nucleates from the impact surface and its propagation into the microdamage zone is self-sustained, triggering interior failure. Its velocity increases with increasing shock strength and eventually approaches the shock velocity. The seemingly puzzling phenomena observed in previous experiments, including incubation time, failure wave velocity variations, and surface roughness effects, can all be explained consistently with the nucleation and growth of the microdamage, and the effects of loading strength and preexisting defects.

  13. Shock compression dynamics under a microscope

    NASA Astrophysics Data System (ADS)

    Dlott, Dana D.

    2017-01-01

    Our laboratory has developed a tabletop laser miniflyer launcher used for a wide variety of studies in the physical and chemical sciences. The flyers, typically 0.7 mm in diameter, can be used to shock microgram quantities of interesting materials. Frequently 100 shock experiments per day are performed. A microscope objective transmits the photon Doppler velocimeter (PDV) flyer plate diagnostic and various laser beams, and collects signals from the shocked materials that can be transmitted to video cameras, spectrographs, streak cameras, etc. In this paper I describe the flyer plate apparatus and then discuss three recent efforts: (1) Shock dissipation in nanoporous media; (2) Probing micropressures in shocked microstructured media; and (3) Shock initiation of nanotechnology reactive materials.

  14. Existence Regions of Shock Wave Triple Configurations

    ERIC Educational Resources Information Center

    Bulat, Pavel V.; Chernyshev, Mikhail V.

    2016-01-01

    The aim of the research is to create the classification for shock wave triple configurations and their existence regions of various types: type 1, type 2, type 3. Analytical solutions for limit Mach numbers and passing shock intensity that define existence region of every type of triple configuration have been acquired. The ratios that conjugate…

  15. Shock induced damage and damage threshold of optical K9 glass investigated by laser-driven shock wave

    NASA Astrophysics Data System (ADS)

    Song, Yunfei; Yu, Guoyang; Jiang, Lilin; Zheng, Xianxu; Liu, Yuqiang; Yang, Yanqiang

    2011-04-01

    The shock wave driven by short laser pulse is used to study the damage of brittle material K9 glass. The damage morphology of K9 glass surface indicates that the material has experienced different loading modes, respectively, at the central area and the surrounding area of the shock wave. At the central area of shock wave, the wavefront is plane and has a uniform pressure distribution, the material mainly suffers a longitudinal shock pressure; but on the edge the shock wave, the wavefront is approximately spherical, besides longitudinal pressure, transverse tensile stress will emerge inside the material. In the latter case, the damage threshold of the material is much smaller than that in the case of compressing by longitudinal pressure only. According to the relationship between damage area and shock pressure, an experimental method is proposed to measure the damage threshold of materials under shock loading. The damage threshold of K9 glass under spherical shock wave is measured to be about 1.12 GPa; and the damage threshold under plane shock wave is estimated to be between 1.82 and 1.98 GPa. They are much bigger than the damage threshold under static pressure. This method could also be used to measure the damage threshold of other materials when loaded by dynamic pressure.

  16. Extracorporeal shock wave lithotripsy in childhood

    SciTech Connect

    Kroovand, R.L.; Harrison, L.H.; McCullough, D.L.

    1987-10-01

    Extracorporeal shock wave lithotripsy is the treatment of choice for the majority of upper urinary calculi in adults. Technical limitations, including patient size and concerns over post-treatment stone fragment passage, have made the application of extracorporeal shock wave lithotripsy in children less clearly defined. We report the successful application of the Dornier lithotriptor in the management of 18 children (22 kidneys) with upper urinary calculi.

  17. Nonlinear Fresnel diffraction of weak shock waves.

    PubMed

    Coulouvrat, François; Marchiano, Régis

    2003-10-01

    Fresnel diffraction at a straight edge is revisited for nonlinear acoustics. Considering the penumbra region as a diffraction boundary layer governed by the KZ equation and its associated jump relations for shocks, similarity laws are established for the diffraction of a step shock, an "N" wave, or a periodic sawtooth wave. Compared to the linear case described by the well-known Fresnel functions, it is shown that weak shock waves penetrate more deeply into the shadow zone than linear waves. The thickness of the penumbra increases as a power of the propagation distance, power 1 for a step shock, or 3/4 for an N wave, as opposed to power 1/2 for a periodic sawtooth wave or a linear wave. This is explained considering the frequency spectrum of the waveform and its nonlinear evolution along the propagation, and is confirmed by direct numerical simulations of the KZ equation. New formulas for the Rayleigh/Fresnel distance in the case of nonlinear diffraction of weak shock waves by a large, finite aperture are deduced from the present study.

  18. Isentropic compressive wave generator impact pillow and method of making same

    DOEpatents

    Barker, Lynn M.

    1985-01-01

    An isentropic compressive wave generator and method of making same. The w generator comprises a disk or flat "pillow" member having component materials of different shock impedances formed in a configuration resulting in a smooth shock impedance gradient over the thickness thereof for interpositioning between an impactor member and a target specimen for producing a shock wave of a smooth predictable rise time. The method of making the pillow member comprises the reduction of the component materials to a powder form and forming the pillow member by sedimentation and compressive techniques.

  19. Generalized Sagdeev potential theory for shock waves modeling

    NASA Astrophysics Data System (ADS)

    Akbari-Moghanjoughi, M.

    2017-05-01

    In this paper, we develop an innovative approach to study the shock wave propagation using the Sagdeev potential method. We also present an analytical solution for Korteweg de Vries Burgers (KdVB) and modified KdVB equation families with a generalized form of the nonlinearity term which agrees well with the numerical one. The novelty of the current approach is that it is based on a simple analogy of the particle in a classical potential with the variable particle energy providing one with a deeper physical insight into the problem and can easily be extended to more complex physical situations. We find that the current method well describes both monotonic and oscillatory natures of the dispersive-diffusive shock structures in different viscous fluid configurations. It is particularly important that all essential parameters of the shock structure can be deduced directly from the Sagdeev potential in small and large potential approximation regimes. Using the new method, we find that supercnoidal waves can decay into either compressive or rarefactive shock waves depending on the initial wave amplitude. Current investigation provides a general platform to study a wide range of phenomena related to nonlinear wave damping and interactions in diverse fluids including plasmas.

  20. Shock-wave dynamics during oil-filled transformer explosions

    NASA Astrophysics Data System (ADS)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Utkin, A. V.

    2016-08-01

    This paper presents a numerical and experimental study of the shock-wave processes evolving inside a closed vessel filled with mineral oil. Obtained experimental Hugoniot data for oil are compared with the corresponding data for water. It is found that compression of mineral oil and water can be described by approximately the same Hugoniot over a wide pressure range. Such similarity allows the use of water instead of mineral oil in the transformer explosion experiments and to describe the compression processes in both liquids using similar equations of state. The Kuznetsov equation of state for water is adopted for a numerical study of mineral oil compression. The features of the evolution of shock waves within mineral oil are analyzed using two-dimensional numerical simulations. Numerical results show that different energy sources may cause different scenarios of loading on the shell. The principal point is the phase transition taking place at relatively high temperatures for the case of high-power energy sources. In this case, a vapor-gaseous bubble emerges that qualitatively changes the dynamics of compression waves and the pattern of loads induced on the shell. Taking into account the features of the process together with the concept of water-oil similarity, the present work presents a new approach for experimental modeling of transformer shell destruction using an explosion with given characteristics in a water-filled shell.

  1. Shock-wave dynamics during oil-filled transformer explosions

    NASA Astrophysics Data System (ADS)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Utkin, A. V.

    2017-05-01

    This paper presents a numerical and experimental study of the shock-wave processes evolving inside a closed vessel filled with mineral oil. Obtained experimental Hugoniot data for oil are compared with the corresponding data for water. It is found that compression of mineral oil and water can be described by approximately the same Hugoniot over a wide pressure range. Such similarity allows the use of water instead of mineral oil in the transformer explosion experiments and to describe the compression processes in both liquids using similar equations of state. The Kuznetsov equation of state for water is adopted for a numerical study of mineral oil compression. The features of the evolution of shock waves within mineral oil are analyzed using two-dimensional numerical simulations. Numerical results show that different energy sources may cause different scenarios of loading on the shell. The principal point is the phase transition taking place at relatively high temperatures for the case of high-power energy sources. In this case, a vapor-gaseous bubble emerges that qualitatively changes the dynamics of compression waves and the pattern of loads induced on the shell. Taking into account the features of the process together with the concept of water-oil similarity, the present work presents a new approach for experimental modeling of transformer shell destruction using an explosion with given characteristics in a water-filled shell.

  2. Shock compression of condensed matter using Eulerian multimaterial method: Applications to multidimensional shocks, deflagration, detonation, and laser ablation

    SciTech Connect

    Yoh, Jack J.; Kim, Ki-hong

    2008-06-01

    The reactive flow analysis of high energy material is performed using hydro shock compression of condensed matter (SCCM) tool that is being developed for handling complex multimaterial dynamics involving energetic and inert matters. Typically, the reacting flows of high energy materials such as fires and explosions give rise to strong nonlinear shock waves and high strain rate deformation of metallic confinements at unusually high pressure and temperature. In order to address difficulties associated with analyzing such complex systems, we have developed a suite of modeling capabilities for elegantly handling large gradients and high strain rates in solids as well as reactive shock waves present in gaseous phase. Mathematical formulation of explosive dynamics involving condensed matter is explained with an emphasis on validating and application of hydro-SCCM to a series of problems of high-speed multimaterial dynamics in nature. A detailed numerical description of a level-set based reactive ghost fluid approach is reported in a separate paper.

  3. Peculiarities of evolution of shock waves generated by boiling coolant

    NASA Astrophysics Data System (ADS)

    Alekseev, M. V.; Vozhakov, I. S.; Lezhnin, S. I.; Pribaturin, N. A.

    2016-11-01

    Simulation of compression wave generation and evolution at the disk target was performed for the case of explosive-type boiling of coolant; the boiling is initiated by endwall rupture of a high-pressure pipeline. The calculations were performed for shock wave amplitude at different times and modes of pipe rupture. The simulated pressure of a target-reflected shock wave is different from the theoretical value for ideal gas; this discrepancy between simulation and theory becomes lower at higher distances of flow from the nozzle exit. Comparative simulation study was performed for flow of two-phase coolant with account for slip flow effect and for different sizes of droplets. Simulation gave the limiting droplet size when the single-velocity homogeneous flow model is valid, i.e., the slip flow effect is insignificant.

  4. Finite Mach number spherical shock wave, application to shock ignition

    SciTech Connect

    Vallet, A.; Ribeyre, X.; Tikhonchuk, V.

    2013-08-15

    A converging and diverging spherical shock wave with a finite initial Mach number M{sub s0} is described by using a perturbative approach over a small parameter M{sub s}{sup −2}. The zeroth order solution is the Guderley's self-similar solution. The first order correction to this solution accounts for the effects of the shock strength. Whereas it was constant in the Guderley's asymptotic solution, the amplification factor of the finite amplitude shock Λ(t)∝dU{sub s}/dR{sub s} now varies in time. The coefficients present in its series form are iteratively calculated so that the solution does not undergo any singular behavior apart from the position of the shock. The analytical form of the corrected solution in the vicinity of singular points provides a better physical understanding of the finite shock Mach number effects. The correction affects mainly the flow density and the pressure after the shock rebound. In application to the shock ignition scheme, it is shown that the ignition criterion is modified by more than 20% if the fuel pressure prior to the final shock is taken into account. A good agreement is obtained with hydrodynamic simulations using a Lagrangian code.

  5. A study of the weak shock wave propagating over a porous wall/cavity system

    NASA Astrophysics Data System (ADS)

    Kim, H. D.; Jung, S. J.; Aoki, T.; Setoguchi, T.

    2005-12-01

    The present computational study addresses the attenuation of the shock wave propagating in a duct, using a porous wall/cavity system. In the present study, a weak shock wave propagating over the porous wall/cavity system is investigated with computational fluid dynamics. A total variation diminishing scheme is employed to solve the unsteady, two-dimensional, compressible, Navier-Stokes equations. The Mach number of an initial shock wave is changed in the range from 1.02 to 1.12. Several different types of porous wall/cavity systems are tested to investigate the passive control effects. The results show that wall pressure strongly fluctuates due to diffraction and reflection processes of the shock waves behind the incident shock wave. From the results, it is understood that for effective alleviation of tunnel impulse waves, the length of the perforated region should be sufficiently long.

  6. Fluorescence depolarization measurements under shock compression

    NASA Astrophysics Data System (ADS)

    Wang, Jue; Banishev, Alexandr; Bassett, Will P.; Dlott, Dana D.

    2017-01-01

    Measurements of the time-dependent fluorescence depolarization of emissive probe molecules enable real-time observations of molecular rotations in shocked materials. In shocked solids, molecular rotations occur as a result of shear deformations. An apparatus is described to measure time-dependent fluorescence depolarization of shocked materials using laser-driven flyer plates and either a picosecond or a nanosecond probe laser. The emission was separated into parallel and perpendicular channels and imaged onto a streak camera. Time-dependent fluorescence depolarization of rhodamine 6G (R6G) dye dissolved in poly-methyl methacrylate (PMMA) was measured with a 16 ns duration impact at 1 km s-1. A partial depolarization of the dye emission was observed to occur during a 150 ns period after the shock.

  7. Attenuation of a shock wave in organoplastic

    SciTech Connect

    Bordzilovskii, S.A.; Karakhanov, S.M.; Merzhievskii, L.A.; Resnyanskii, A.D.

    1995-09-01

    The attenuation of a plane shock wave in organoplastic was experimentally and numerically investigated during its interaction with an overtaking rarefaction wave. Measurements were carried out with manganin gauges. An earlier formulation model of the dynamic deformation of composites was used in calculations. A comparison of calculated and experimental data has shown their good agreement.

  8. a Study of the Shock Sensitivity of PBX 9501 Damaged by Compressive Loading

    NASA Astrophysics Data System (ADS)

    Thompson, D. G.; Gustavsen, R. L.; Hooks, D. E.; Peterson, P. D.; DeLuca, R.; Stahl, D. B.; Hagelberg, S. I.; Alcon, R. R.

    2007-12-01

    We have studied the effects of damage caused by compressive loading on the shock sensitivity of the plastic bonded explosive PBX 9501. PBX 9501 consists of 95 wt. % HMX and 5 wt. % nitroplasticized Estane binder. The binder is a mixture of 49 wt. % Estane® 5703 (BF Goodrich), 49 wt. % Nitroplasticizer (a eutectic mixture of bis(2,2-dinitropropyl)formal and bis(2,2 dinitropropyl)acetal), and 2 wt. % Irganox® 1010 stabilizer. PBX 9501 cubes, 25.4 mm on a side, were compressed to various uniaxial loads in an Instron machine. After loading, 10×10 mm cross-sections, 3.5 mm thick, were taken from the center of each cube. These slices were then subjected to nearly identical 35 kbar shocks. Transmitted shock wave profiles were measured using interface velocimetry (VISAR). Comparison of shock wave growth is a measure of shock sensitivity. Results on four samples indicate little change in sensitivity caused by compressive loading.

  9. Plasma shock waves excited by THz radiation

    NASA Astrophysics Data System (ADS)

    Rudin, S.; Rupper, G.; Shur, M.

    2016-10-01

    The shock plasma waves in Si MOS, InGaAs and GaN HEMTs are launched at a relatively small THz power that is nearly independent of the THz input frequency for short channel (22 nm) devices and increases with frequency for longer (100 nm to 1 mm devices). Increasing the gate-to-channel separation leads to a gradual transition of the nonlinear waves from the shock waves to solitons. The mathematics of this transition is described by the Korteweg-de Vries equation that has the single propagating soliton solution.

  10. Holographic interferometric observation of shock wave focusing to extracorporeal shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Takayama, Kazuyoshi; Obara, Tetsuro; Onodera, Osamu

    1991-04-01

    Underwater shock wave focusing is successfully applied to disintegrate and remove kidney stones or gallbladder stones without using surgical operations. This treatment is one of the most peaceful applications ofshock waves and is named as the Extracorporeal Shock Wave Lithotripsy. Ajoint research project is going on between the Institute ofFluid Science, Tohoku University and the School ofMedicine, Tohoku University. The paper describes a result of the fundamental research on the underwater shock wave focusing applied to the ESWL. Quantitatively to visualize the underwater shock waves, various optical flow visualization techniques were successfully used such as holographic interferometry, and shadowgraphs combined with Ima-Con high speed camera. Double exposure holographic interferometric observation revealed the mechanism of generation, propagation and focusing of underwater shock waves. The result of the present research was already used to manufacture a prototype machine and it has already been applied successfully to ESWL crinical treatments. However, despite of success in the clinical treatments, important fundamental questions still remain unsolved, i.e., effects of underwater shock wave focusing on tissue damage during the treatment. Model experiments were conducted to clarify mechanism of the tissue damage associated with the ESWL. Shock-bubble interactions were found responsible to the tissue damage during the ESWL treatment. In order to interprete experimental findings and to predict shock wave behavior and high pressures, a numerical simulation was carried. The numerical results agreed with the experiments.

  11. Comparison of geometrical shock dynamics and kinematic models for shock-wave propagation

    NASA Astrophysics Data System (ADS)

    Ridoux, J.; Lardjane, N.; Monasse, L.; Coulouvrat, F.

    2017-09-01

    Geometrical shock dynamics (GSD) is a simplified model for nonlinear shock-wave propagation, based on the decomposition of the shock front into elementary ray tubes. Assuming small changes in the ray tube area, and neglecting the effect of the post-shock flow, a simple relation linking the local curvature and velocity of the front, known as the A{-}M rule, is obtained. More recently, a new simplified model, referred to as the kinematic model, was proposed. This model is obtained by combining the three-dimensional Euler equations and the Rankine-Hugoniot relations at the front, which leads to an equation for the normal variation of the shock Mach number at the wave front. In the same way as GSD, the kinematic model is closed by neglecting the post-shock flow effects. Although each model's approach is different, we prove their structural equivalence: the kinematic model can be rewritten under the form of GSD with a specific A{-}M relation. Both models are then compared through a wide variety of examples including experimental data or Eulerian simulation results when available. Attention is drawn to the simple cases of compression ramps and diffraction over convex corners. The analysis is completed by the more complex cases of the diffraction over a cylinder, a sphere, a mound, and a trough.

  12. Extracorporeal shock wave therapy for tendinopathies.

    PubMed

    Seil, Romain; Wilmes, Philippe; Nührenbörger, Christian

    2006-07-01

    Shock waves, as applied in urology and gastroenterology, were introduced in the middle of the last decade in Germany to treat different pathologies of the musculoskeletal system, including epicondylitis of the elbow, plantar fasciitis, and calcifying and noncalcifying tendinitis of the rotator cuff. With the noninvasive nature of these waves and their seemingly low complication rate, extracorporeal shock wave therapy (ESWT) seemed a promising alternative to the established conservative and surgical options in the treatment of patients with chronically painful conditions. However, the apparent advantages of the method led to a rapid diffusion and even inflationary use of ESWT; prospective, randomized studies on the mechanisms and effects of shock waves on musculoskeletal tissues were urgently needed to define more accurate indications and optimize therapeutic outcome. This review covers recent international research in the field and presents actual indications and results in therapy of musculoskeletal conditions with ESWT.

  13. Weak-shock theory for spherical shock waves

    SciTech Connect

    Curtis, W.D.; Rosenkilde, C.E.; Yee, K.S.

    1982-03-01

    We develop weak shock theory in a form which would allow us to utilize output from a hydrodynamic code (e.g. KOVEC) as either an initial or boundary condition and then follow the wave evolution to much greater distances than the codes themselves can attain.

  14. Stishovite: Synthesis by shock wave

    USGS Publications Warehouse

    De Carli, P. S.; Milton, D.J.

    1965-01-01

    Small amounts of stishovite were separated from specimens of explosively shocked sandstones, novaculite, and single-crystal quartz. Estimated peak pressures for the syntheses ranged from 150 to 280 kilobars, and shock temperatures were from 150?? to 900??C. No coesite was detected in any sample. It is suggested that quartz can invert during shock to a short-range-order phase, with sixfold coordination. A small portion of this phase may develop the long-range order of stishovite, and, during the more protracted decrease of the pressure pulse through the stability field of coesite accompanying meteorite crater formation, a portion may invert to coesite.

  15. Stishovite: Synthesis by Shock Wave.

    PubMed

    De Carli, P S; Milton, D J

    1965-01-08

    Small amounts of stishovite were separated from specimens of explosively shocked sandstones, novaculite, and single-crystal quartz. Estimated peak pressures for the syntheses ranged from 150 to 280 kilobars, and shock temperatures were from 150 degrees to 900 degrees C. No coesite was detected in any sample. It is suggested that quartz can invert during shock to a short-range-order phase, with sixfold coordination. A small portion of this phase may develop the long-range order of stishovite, and, during the more protracted decrease of the pressure pulse through the stability field of coesite accompanying meteorite crater formation, a portion may invert to coesite.

  16. Proton radiography of a shock-compressed target

    SciTech Connect

    Ravasio, A.; Benuzzi-Mounaix, A.; Loupias, B.; Ozaki, N.; Vinci, T.; Koenig, M.; Romagnani, L.; Cecchetti, C.; Borghesi, M.; Le Pape, S.; Hicks, D.; MacKinnon, A.; Park, H. S.; Patel, P.; Batani, D.; Dezulian, R.; Boehly, T.; Gremillet, L.; Henry, E.; Schiavi, A.

    2010-07-15

    In this paper we report on the radiography of a shock-compressed target using laser produced proton beams. A low-density carbon foam target was shock compressed by long pulse high-energy laser beams. The shock front was transversally probed with a proton beam produced in the interaction of a high intensity laser beam with a gold foil. We show that from radiography data, the density profile in the shocked target can be deduced using Monte Carlo simulations. By changing the delay between long and short pulse beams, we could probe different plasma conditions and structures, demonstrating that the details of the steep density gradient can be resolved. This technique is validated as a diagnostic for the investigation of warm dense plasmas, allowing an in situ characterization of high-density contrasted plasmas.

  17. Turbulent Water Coupling in Shock Wave Lithotripsy

    PubMed Central

    Lautz, Jaclyn; Sankin, Georgy; Zhong, Pei

    2013-01-01

    Previous studies have demonstrated that stone comminution decreases with increased pulse repetition frequency as a result of bubble proliferation in the cavitation field of a shock wave lithotripter (Pishchalnikov et al., 2011). If cavitation nuclei remain in the propagation path of successive lithotripter pulses, especially in the acoustic coupling cushion of the shock wave source, they will consume part of the incident wave energy, leading to reduced tensile pressure in the focal region and thus lower stone comminution efficiency. We introduce a method to remove cavitation nuclei from the coupling cushion between successive shock exposures using a jet of degassed water. As a result, pre-focal bubble nuclei lifetime quantified by B-mode ultrasound imaging was reduced from 7 s to 0.3 s by a jet with an exit velocity of 62 cm/s. Stone fragmentation (percent mass < 2 mm) after 250 shocks delivered at 1 Hz was enhanced from 22 ± 6% to 33 ± 5% (p = 0.007) in water without interposing tissue mimicking materials. Stone fragmentation after 500 shocks delivered at 2 Hz was increased from 18 ± 6% to 28 ± 8% (p = 0.04) with an interposing tissue phantom of 8 cm thick. These results demonstrate the critical influence of cavitation bubbles in the coupling cushion on stone comminution and suggest a potential strategy to improve the efficacy of contemporary shock wave lithotripters. PMID:23322027

  18. Turbulent water coupling in shock wave lithotripsy.

    PubMed

    Lautz, Jaclyn; Sankin, Georgy; Zhong, Pei

    2013-02-07

    Previous studies have demonstrated that stone comminution decreases with increased pulse repetition frequency as a result of bubble proliferation in the cavitation field of a shock wave lithotripter (Pishchalnikov et al 2011 J. Acoust. Soc. Am. 130 EL87-93). If cavitation nuclei remain in the propagation path of successive lithotripter pulses, especially in the acoustic coupling cushion of the shock wave source, they will consume part of the incident wave energy, leading to reduced tensile pressure in the focal region and thus lower stone comminution efficiency. We introduce a method to remove cavitation nuclei from the coupling cushion between successive shock exposures using a jet of degassed water. As a result, pre-focal bubble nuclei lifetime quantified by B-mode ultrasound imaging was reduced from 7 to 0.3 s by a jet with an exit velocity of 62 cm s(-1). Stone fragmentation (percent mass <2 mm) after 250 shocks delivered at 1 Hz was enhanced from 22 ± 6% to 33 ± 5% (p = 0.007) in water without interposing tissue mimicking materials. Stone fragmentation after 500 shocks delivered at 2 Hz was increased from 18 ± 6% to 28 ± 8% (p = 0.04) with an interposing tissue phantom of 8 cm thick. These results demonstrate the critical influence of cavitation bubbles in the coupling cushion on stone comminution and suggest a potential strategy to improve the efficacy of contemporary shock wave lithotripters.

  19. Laser driven single shock compression of fluid deuterium from 45 to 220 GPa

    SciTech Connect

    Hicks, D; Boehly, T; Celliers, P; Eggert, J; Moon, S; Meyerhofer, D; Collins, G

    2008-03-23

    The compression {eta} of liquid deuterium between 45 and 220 GPa under laser-driven shock loading has been measured using impedance matching to an aluminum (Al) standard. An Al impedance match model derived from a best fit to absolute Hugoniot data has been used to quantify and minimize the systematic errors caused by uncertainties in the high-pressure Al equation of state. In deuterium below 100 GPa results show that {eta} {approx_equal} 4.2, in agreement with previous impedance match data from magnetically-driven flyer and convergent-explosive shock wave experiments; between 100 and 220 GPa {eta} reaches a maximum of {approx}5.0, less than the 6-fold compression observed on the earliest laser-shock experiments but greater than expected from simple extrapolations of lower pressure data. Previous laser-driven double-shock results are found to be in good agreement with these single-shock measurements over the entire range under study. Both sets of laser-shock data indicate that deuterium undergoes an abrupt increase in compression at around 110 GPa.

  20. Damage mechanisms in shock wave lithotripsy (SWL)

    NASA Astrophysics Data System (ADS)

    Lokhandwalla, Murtuza

    Shock wave lithotripsy is a 'non-invasive' therapy for treating kidney stones. Focused shock waves fragment stones to a size that can be passed naturally. There is, however, considerable tissue injury, and the mechanisms of stone fragmentation and tissue injury are not well understood. This work investigates potential tissue damage mechanisms, with an aim towards enhancing stone fragmentation and minimizing tissue damage. Lysis of red blood cells (RBC's) due to in vitro exposure to shock waves was investigated. Fluid flow-fields induced by a non-uniform shock wave, as well as radial expansion/implosion of a bubble was hypothesized to cause cell lysis. Both the above flow-fields constitute an unsteady extensional flow, exerting inertial as well as viscous forces on the RBC membrane. The resultant membrane tension and the membrane areal strain due to the above flow-fields were estimated. Both were found to exert a significantly higher inertial force (50--100 mN/m) than the critical membrane tension (10 mN/m). Bubble-induced flow-field was estimated to last for a longer duration (˜1 microsec) compared to the shock-induced flow (˜1 ns) and hence, was predicted to be lytically more effective, in typical in vitro experimental conditions. However, in vivo conditions severely constrain bubble growth, and cell lysis due to shock-induced shear could be dominant. Hemolysis due to shock-induced shear, in absence of cavitation, was experimentally investigated. The lithotripter-generated shock wave was refocused by a parabolic reflector. This refocused wave-field had a tighter focus (smaller beam-width and a higher amplitude) than the lithotripter wave-field. Cavitation was eliminated by applying overpressure to the fluid. Acoustic emissions due to bubble activity were monitored by a novel passive cavitation detector (HP-PCD). Aluminum foils were also used to differentiate cavitational from non-cavitational mode of damage. RBC's were exposed to the reflected wave-field from

  1. Shock wave loading of a magnetic guide

    NASA Astrophysics Data System (ADS)

    Kindt, L.

    2011-10-01

    velocities and a shock wave is created between the two velocity regions. In order to conserve number of particle, momentum and enthalpy the density of the atomic beam passing through the shock wave must increase. We have build such a shock wave in an atomic beam and observed the density increase due to this. As an extra feature having a subsonic beam on a downward slope adds an extra density increase due to gravitational compression. Loading ultra cold atoms into a 3D trap from the dense subsonic beam overcomes the problem with 2D cooling and thermal conductivity. This was done and evaporative cooling was applied creating an unprecedented large number rubidium BEC.

  2. Shock Wave Structure Mediated by Energetic Particles

    NASA Astrophysics Data System (ADS)

    Mostafavi, P.; Zank, G. P.; Webb, G. M.

    2016-12-01

    Energetic particles such as cosmic rays, Pick Up Ions (PUIs), and solar energetic particles can affect all facets of plasma physics and astrophysical plasma. Energetic particles play an especially significant role in the dissipative process at shocks and in determining their structure. The very interesting recent observations of shocks in the inner heliosphere found that many shocks appear to be significantly mediated by solar energetic particles which have a pressure that exceeds considerably both the thermal gas pressure and the magnetic field pressure. Energetic particles contribute an isotropic scalar pressure to the plasma system at the leading order, as well as introducing dissipation via a collisionless heat flux (diffusion) at the next order and a collisionless stress tensor (viscosity) at the second order. Cosmic-ray modified shocks were discussed by Axford et al. (1982), Drury (1983), and Webb (1983). Zank et al. (2014) investigated the incorporation of PUIs in the supersonic solar wind beyond 10AU, in the inner Heliosheath and in the Very Local Interstellar Medium. PUIs do not equilibrate collisionally with the background plasma in these regimes. In the absence of equilibration between plasma components, a separate coupled plasma description for the energetic particles is necessary. This model is used to investigate the structure of shock waves assuming that we can neglect the magnetic field. Specifically, we consider the dissipative role that both the energetic particle collisionless heat flux and viscosity play in determining the structure of collisionless shock waves. We show that the incorporation of both energetic particle collisionless heat flux and viscosity is sufficient to completely determine the structure of a shock. Moreover, shocks with three sub-shocks converge to the weak sub-shocks. This work differs from the investigation of Jokipii and Williams (1992) who restricted their attention to a cold thermal gas. For a cold thermal non

  3. Hypersonic flow separation in shock wave boundary layer interactions

    NASA Technical Reports Server (NTRS)

    Hamed, A.; Kumar, Ajay

    1992-01-01

    An assessment is presented for the experimental data on separated flow in shock wave turbulent boundary layer interactions at hypersonic and supersonic speeds. The data base consists mainly of two dimensional and axisymmetric interactions in compression corners or cylinder-flares, and externally generated oblique shock interactions with boundary layers over flat plates or cylindrical surfaces. The conditions leading to flow separation and the subsequent changes in the flow empirical correlations for incipient separation are reviewed. The effects of the Mach number, Reynolds number, surface cooling and the methods of detecting separation are discussed. The pertinent experimental data for the separated flow characteristics in separated turbulent boundary layer shock interaction are also presented and discussed.

  4. Hypersonic flow separation in shock wave boundary layer interactions

    NASA Technical Reports Server (NTRS)

    Hamed, A.; Kumar, Ajay

    1992-01-01

    An assessment is presented for the experimental data on separated flow in shock wave turbulent boundary layer interactions at hypersonic and supersonic speeds. The data base consists mainly of two dimensional and axisymmetric interactions in compression corners or cylinder-flares, and externally generated oblique shock interactions with boundary layers over flat plates or cylindrical surfaces. The conditions leading to flow separation and the subsequent changes in the flow empirical correlations for incipient separation are reviewed. The effects of the Mach number, Reynolds number, surface cooling and the methods of detecting separation are discussed. The pertinent experimental data for the separated flow characteristics in separated turbulent boundary layer shock interaction are also presented and discussed.

  5. A study of the liquefaction shock wave structure

    SciTech Connect

    Saltz, D.; Guelen, S.C.

    1996-05-01

    The system of shock wave-induced vapor condensation in fluids of large heat capacity has been investigated theoretically. The wave structure is governed by differences in the time scales associated with various relaxation mechanisms and their coupling to the macroscopic flow. In the low to moderate Mach number range, the viscous and heat-conducting forces are localized within a discontinuous forerunner wave, while the slower nucleation and droplet growth processes are resolved inside a trailing condensation wave. A time-dependent analysis of the fluid motion is required because the phase transition can occur too slowly for the system to reach a steady state on the laboratory time scale. In the high Mach number regime, a steady-state motion is rapidly attained, but the analysis requires a simultaneous treatment of nucleation, viscosity, and heat conduction. It appears that instability mechanisms similar to the ones found in ZND detonation waves are responsible for the shock-front irregularities observed in high Mach-number flows. Based on the rapidity of the supersaturating shock compression and the time delay of nucleation, it is anticipated that metastable states near the vapor spinodal are attainable, especially at high temperatures. {copyright} {ital 1996 American Institute of Physics.}

  6. A study of the liquefaction shock wave structure

    NASA Astrophysics Data System (ADS)

    Saltz, D.; Gülen, S. C.

    1996-05-01

    The system of shock wave-induced vapor condensation in fluids of large heat capacity has been investigated theoretically. The wave structure is governed by differences in the time scales associated with various relaxation mechanisms and their coupling to the macroscopic flow. In the low to moderate Mach number range, the viscous and heat-conducting forces are localized within a discontinuous forerunner wave, while the slower nucleation and droplet growth processes are resolved inside a trailing condensation wave. A time-dependent analysis of the fluid motion is required because the phase transition can occur too slowly for the system to reach a steady state on the laboratory time scale. In the high Mach number regime, a steady-state motion is rapidly attained, but the analysis requires a simultaneous treatment of nucleation, viscosity, and heat conduction. It appears that instability mechanisms similar to the ones found in ZND detonation waves are responsible for the shock-front irregularities observed in high Mach-number flows. Based on the rapidity of the supersaturating shock compression and the time delay of nucleation, it is anticipated that metastable states near the vapor spinodal are attainable, especially at high temperatures.

  7. Calculation of the flow field in supersonic mixed-compression inlets at angle of attack using the three-dimensional method of characteristics with discrete shock wave fitting

    NASA Technical Reports Server (NTRS)

    Vadyak, J.; Hoffman, J. D.

    1978-01-01

    The influence of molecular transport is included in the computation by treating viscous and thermal diffusion terms in the governing partial differential equations as correction terms in the method of characteristics scheme. The development of a production type computer program is reported which is capable of calculating the flow field in a variety of axisymmetric mixed-compression aircraft inlets. The results agreed well with those produced by the two-dimensional method characteristics when axisymmetric flow fields are computed. For three-dimensional flow fields, the results agree well with experimental data except in regions of high viscous interaction and boundary layer removal.

  8. Nonplanar Shock Waves in Dusty Plasmas

    SciTech Connect

    Mamun, A. A.; Shukla, P. K.

    2011-11-29

    Nonplanar (viz. cylindrical and spherical) electro-acoustic [dust-ion-acoustic (DIA) and dust-acoustic (DA)] shock waves have been investigated by employing the reductive perturbation method. The dust charge fluctuation (strong correlation among highly charged dust) is the source of dissipation, and is responsible for the formation of the DIA (DA) shock structures. The effects of cylindrical and spherical geometries on the time evolution of DIA and DA shock structures are examined and identified. The combined effects of vortex-like electron distribution and dust charge fluctuation (dust-correlation and effective dust-temperature) on the basic features of nonplanar DIA (DA) shock waves are pinpointed. The implications of our results in laboratory dusty plasma experiments are briefly discussed.

  9. Nonplanar Shock Waves in Dusty Plasmas

    NASA Astrophysics Data System (ADS)

    Mamun, A. A.; Shukla, P. K.

    2011-11-01

    Nonplanar (viz. cylindrical and spherical) electro-acoustic [dust-ion-acoustic (DIA) and dust-acoustic (DA)] shock waves have been investigated by employing the reductive perturbation method. The dust charge fluctuation (strong correlation among highly charged dust) is the source of dissipation, and is responsible for the formation of the DIA (DA) shock structures. The effects of cylindrical and spherical geometries on the time evolution of DIA and DA shock structures are examined and identified. The combined effects of vortex-like electron distribution and dust charge fluctuation (dust-correlation and effective dust-temperature) on the basic features of nonplanar DIA (DA) shock waves are pinpointed. The implications of our results in laboratory dusty plasma experiments are briefly discussed.

  10. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    DOE PAGES

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-21

    Shock compression experiments in the few hundred GPa (multi-Mbar) regime were performed on Lithium Deuteride single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17–32 km/s. Measurements included pressure, density, and temperature between ~190 and 570 GPa along the Principal Hugoniot—the locus of end states achievable through compression by large amplitude shock waves—as well as pressure and density of reshock states up to ~920 GPa. As a result, the experimental measurements are compared with density functional theory calculations, tabular equation ofmore » state models, and legacy nuclear driven results that have been reanalyzed using modern equations of state for the shock wave standards used in the experiments.« less

  11. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    SciTech Connect

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-21

    Shock compression experiments in the few hundred GPa (multi-Mbar) regime were performed on Lithium Deuteride single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17–32 km/s. Measurements included pressure, density, and temperature between ~190 and 570 GPa along the Principal Hugoniot—the locus of end states achievable through compression by large amplitude shock waves—as well as pressure and density of reshock states up to ~920 GPa. As a result, the experimental measurements are compared with density functional theory calculations, tabular equation of state models, and legacy nuclear driven results that have been reanalyzed using modern equations of state for the shock wave standards used in the experiments.

  12. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    SciTech Connect

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-21

    Shock compression experiments in the few hundred GPa (multi-Mabr) regime were performed on Lithium Deuteride (LiD) single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17-32 km/s. Measurements included pressure, density, and temperature between ~200-600 GPa along the Principal Hugoniot – the locus of end states achievable through compression by large amplitude shock waves – as well as pressure and density of re - shock states up to ~900 GPa. Lastly, the experimental measurements are compared with recent density functional theory calculations as well as a new tabular equation of state developed at Los Alamos National Labs.

  13. High-energy synchrotron X-ray radiography of shock-compressed materials

    NASA Astrophysics Data System (ADS)

    Rutherford, Michael E.; Chapman, David J.; Collinson, Mark A.; Jones, David R.; Music, Jasmina; Stafford, Samuel J. P.; Tear, Gareth R.; White, Thomas G.; Winters, John B. R.; Drakopoulos, Michael; Eakins, Daniel E.

    2015-06-01

    This presentation will discuss the development and application of a high-energy (50 to 250 keV) synchrotron X-ray imaging method to study shock-compressed, high-Z samples at Beamline I12 at the Diamond Light Source synchrotron (Rutherford-Appleton Laboratory, UK). Shock waves are driven into materials using a portable, single-stage gas gun designed by the Institute of Shock Physics. Following plate impact, material deformation is probed in-situ by white-beam X-ray radiography and complimentary velocimetry diagnostics. The high energies, large beam size (13 x 13 mm), and appreciable sample volumes (~ 1 cm3) viable for study at Beamline I12 compliment existing in-house pulsed X-ray capabilities and studies at the Dynamic Compression Sector. The authors gratefully acknowledge the ongoing support of Imperial College London, EPSRC, STFC and the Diamond Light Source, and AWE Plc.

  14. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    SciTech Connect

    Knudson, Marcus D.; Desjarlais, Michael P.; Lemke, Raymond W.

    2014-10-01

    Shock compression experiments in the few hundred GPa (multi-Mabr) regime were performed on Lithium Deuteride (LiD) single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17-32 km/s. Measurements included pressure, density, and temperature between ~200-600 GPa along the Principal Hugoniot – the locus of end states achievable through compression by large amplitude shock waves – as well as pressure and density of re - shock states up to ~900 GPa. Lastly, the experimental measurements are compared with recent density functional theory calculations as well as a new tabular equation of state developed at Los Alamos National Labs.

  15. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    NASA Astrophysics Data System (ADS)

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-01

    Shock compression experiments in the few hundred GPa (multi-Mbar) regime were performed on Lithium Deuteride single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17-32 km/s. Measurements included pressure, density, and temperature between ˜190 and 570 GPa along the Principal Hugoniot—the locus of end states achievable through compression by large amplitude shock waves—as well as pressure and density of reshock states up to ˜920 GPa. The experimental measurements are compared with density functional theory calculations, tabular equation of state models, and legacy nuclear driven results that have been reanalyzed using modern equations of state for the shock wave standards used in the experiments.

  16. Shock compression experiments on Lithium Deuteride (LiD) single crystals

    DOE PAGES

    Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.

    2016-12-21

    Shock compression experiments in the few hundred GPa (multi-Mabr) regime were performed on Lithium Deuteride (LiD) single crystals. This study utilized the high velocity flyer plate capability of the Sandia Z Machine to perform impact experiments at flyer plate velocities in the range of 17-32 km/s. Measurements included pressure, density, and temperature between ~200-600 GPa along the Principal Hugoniot – the locus of end states achievable through compression by large amplitude shock waves – as well as pressure and density of re - shock states up to ~900 GPa. Lastly, the experimental measurements are compared with recent density functional theorymore » calculations as well as a new tabular equation of state developed at Los Alamos National Labs.« less

  17. Shear wave measurements in shock-induced, high-pressure phases

    SciTech Connect

    Aidun, J.B.

    1993-01-01

    Structural phase transformations under shock loading are of considerable interest for understanding the response of solids under nonhydrostatic stresses and at high strain-rates. Examining shock-induced transformations from continuum level measurements is fundamentally constrained by the inability to directly identify microscopic processes, and also by the limited number of material properties that can be directly measured. ne latter limitation can be reduced by measuring both shear and compression waves using Lagrangian gauges in combined, compression and shear loading. The shear wave serves as an important, real-time probe of the shocked state and unloading response. Using results from a recent study of CaCO[sub 3], the unique information obtained from the shear wave speed and the detailed structure of the shear wave are shown to be useful for distinguishing the effects of phase transformations from yielding, as well as in characterizing the high-pressure phases and the yielding process under shock loading.

  18. Shear wave measurements in shock-induced, high-pressure phases

    SciTech Connect

    Aidun, J.B.

    1993-07-01

    Structural phase transformations under shock loading are of considerable interest for understanding the response of solids under nonhydrostatic stresses and at high strain-rates. Examining shock-induced transformations from continuum level measurements is fundamentally constrained by the inability to directly identify microscopic processes, and also by the limited number of material properties that can be directly measured. ne latter limitation can be reduced by measuring both shear and compression waves using Lagrangian gauges in combined, compression and shear loading. The shear wave serves as an important, real-time probe of the shocked state and unloading response. Using results from a recent study of CaCO{sub 3}, the unique information obtained from the shear wave speed and the detailed structure of the shear wave are shown to be useful for distinguishing the effects of phase transformations from yielding, as well as in characterizing the high-pressure phases and the yielding process under shock loading.

  19. Magnetoacoustic shock waves in dissipative degenerate plasmas

    SciTech Connect

    Hussain, S.; Mahmood, S.

    2011-11-15

    Quantum magnetoacoustic shock waves are studied in homogenous, magnetized, dissipative dense electron-ion plasma by using two fluid quantum magneto-hydrodynamic (QMHD) model. The weak dissipation effects in the system are taken into account through kinematic viscosity of the ions. The reductive perturbation method is employed to derive Korteweg-de Vries Burgers (KdVB) equation for magnetoacoustic wave propagating in the perpendicular direction to the external magnetic field in dense plasmas. The strength of magnetoacoustic shock is investigated with the variations in plasma density, magnetic field intensity, and ion kinematic viscosity of dense plasma system. The necessary condition for the existence of monotonic and oscillatory shock waves is also discussed. The numerical results are presented for illustration by using the data of astrophysical dense plasma situations such as neutron stars exist in the literature.

  20. Emission lifetimes of a fluorescent dye under shock compression

    DOE PAGES

    Liu, Wei-long; Bassett, Will P.; Christensen, James M.; ...

    2015-10-15

    The emission lifetimes of rhodamine 6G (R6G), were measured under shock compression to 9.1 GPa, with the dual intent of better understanding molecular photophysics in extreme environments and assessing the usefulness of fluorescence lifetime microscopy to measure spatially-dependent pressure distributions in shocked microstructured media. R6G was studied as free dye dissolved in poly-methyl methacrylate (PMMA), or dye encapsulated in silica microparticles suspended in PMMA. Thin layers of these materials in impedance-matched geometries were subjected to planar single-stage shocks created by laser-driven flyer plates. A synchronized femtosecond laser excited the dye at selected times relative to flyer plate arrival and themore » emission lifetimes were measured with a streak camera. Lifetimes decreased when shocks arrived. The lifetime decrease was attributed to a shock-induced enhancement of R6G nonradiative relaxation. At least part of the relaxation involved shock-enhanced intersystem crossing. For free dye in PMMA, the lifetime decrease during the shock was shown to be a linear function of shock pressure from 0-9 GPa, with a slope of -0.22 ns·GPa-1. Furthermore, the linear relationship makes it simple to convert lifetimes into pressures. Lifetime measurements in shocked microenvironments may be better than emission intensity measurements, since lifetimes are sensitive to the surrounding environment, but insensitive to intensity variations associated with the motion and optical properties of a dynamically changing structure.« less

  1. Emission lifetimes of a fluorescent dye under shock compression

    SciTech Connect

    Liu, Wei-long; Bassett, Will P.; Christensen, James M.; Dlott, Dana D.

    2015-10-15

    The emission lifetimes of rhodamine 6G (R6G), were measured under shock compression to 9.1 GPa, with the dual intent of better understanding molecular photophysics in extreme environments and assessing the usefulness of fluorescence lifetime microscopy to measure spatially-dependent pressure distributions in shocked microstructured media. R6G was studied as free dye dissolved in poly-methyl methacrylate (PMMA), or dye encapsulated in silica microparticles suspended in PMMA. Thin layers of these materials in impedance-matched geometries were subjected to planar single-stage shocks created by laser-driven flyer plates. A synchronized femtosecond laser excited the dye at selected times relative to flyer plate arrival and the emission lifetimes were measured with a streak camera. Lifetimes decreased when shocks arrived. The lifetime decrease was attributed to a shock-induced enhancement of R6G nonradiative relaxation. At least part of the relaxation involved shock-enhanced intersystem crossing. For free dye in PMMA, the lifetime decrease during the shock was shown to be a linear function of shock pressure from 0-9 GPa, with a slope of -0.22 ns·GPa-1. Furthermore, the linear relationship makes it simple to convert lifetimes into pressures. Lifetime measurements in shocked microenvironments may be better than emission intensity measurements, since lifetimes are sensitive to the surrounding environment, but insensitive to intensity variations associated with the motion and optical properties of a dynamically changing structure.

  2. Reflection and Refraction of Acoustic Waves by a Shock Wave

    NASA Technical Reports Server (NTRS)

    Brillouin, J.

    1957-01-01

    The presence of sound waves in one or the other of the fluid regions on either side of a shock wave is made apparent, in the region under superpressure, by acoustic waves (reflected or refracted according to whether the incident waves lie in the region of superpressure or of subpressure) and by thermal waves. The characteristics of these waves are calculated for a plane, progressive, and uniform incident wave. In the case of refraction, the refracted acoustic wave can, according to the incidence, be plane, progressive, and uniform or take the form of an 'accompanying wave' which remains attached to the front of the shock while sliding parallel to it. In all cases, geometrical constructions permit determination of the kinematic characteristics of the reflected or refractive acoustic waves. The dynamic relationships show that the amplitude of the reflected wave is always less than that of the incident wave. The amplitude of the refracted wave, whatever its type, may in certain cases be greater than that of the incident wave.

  3. Laser Light Scattering by Shock Waves

    NASA Technical Reports Server (NTRS)

    Panda, J.; Adamovsky, G.

    1995-01-01

    Scattering of coherent light as it propagates parallel to a shock wave, formed in front of a bluff cylindrical body placed in a supersonic stream, is studied experimentally and numerically. Two incident optical fields are considered. First, a large diameter collimated beam is allowed to pass through the shock containing flow. The light intensity distribution in the resultant shadowgraph image, measured by a low light CCD camera, shows well-defined fringes upstream and downstream of the shadow cast by the shock. In the second situation, a narrow laser beam is brought to a grazing incidence on the shock and the scattered light, which appears as a diverging sheet from the point of interaction, is visualized and measured on a screen placed normal to the laser path. Experiments are conducted on shocks formed at various free-stream Mach numbers, M, and total pressures, P(sub 0). It is found that the widths of the shock shadows in a shadowgraph image become independent of M and P(sub 0) when plotted against the jump in the refractive index, (Delta)n, created across the shock. The total scattered light measured from the narrow laser beam and shock interaction also follows the same trend. In the numerical part of the study, the shock is assumed to be a 'phase object', which introduces phase difference between the upstream and downstream propagating parts of the light disturbances. For a given shape and (Delta)n of the bow shock the phase and amplitude modulations are first calculated by ray tracing. The wave front is then propagated to the screen using the Fresnet diffraction equation. The calculated intensity distribution, for both of the incident optical fields, shows good agreement with the experimental data.

  4. Shock waves from nonspherical cavitation bubbles

    NASA Astrophysics Data System (ADS)

    Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Tinguely, Marc; Dorsaz, Nicolas; Farhat, Mohamed

    2017-09-01

    We present detailed observations of the shock waves emitted at the collapse of single cavitation bubbles using simultaneous time-resolved shadowgraphy and hydrophone pressure measurements. The geometry of the bubbles is systematically varied from spherical to very nonspherical by decreasing their distance to a free or rigid surface or by modulating the gravity-induced pressure gradient aboard parabolic flights. The nonspherical collapse produces multiple shocks that are clearly associated with different processes, such as the jet impact and the individual collapses of the distinct bubble segments. For bubbles collapsing near a free surface, the energy and timing of each shock are measured separately as a function of the anisotropy parameter ζ , which represents the dimensionless equivalent of the Kelvin impulse. For a given source of bubble deformation (free surface, rigid surface, or gravity), the normalized shock energy depends only on ζ , irrespective of the bubble radius R0 and driving pressure Δ p . Based on this finding, we develop a predictive framework for the peak pressure and energy of shock waves from nonspherical bubble collapses. Combining statistical analysis of the experimental data with theoretical derivations, we find that the shock peak pressures can be estimated as jet impact-induced hammer pressures, expressed as ph=0.45 (ρc2Δ p ) 1 /2ζ-1 at ζ >10-3 . The same approach is found to explain the shock energy decreasing as a function of ζ-2 /3.

  5. Excitation of intense shock waves by soft X-radiation from a Z-pinch plasma

    SciTech Connect

    Fortov, V.E.; Dyabilin, K.; Lebedev, M.; Yu, V.O.; Grabovskij, E.; Smirnov, V.; Goel, B.

    1996-05-01

    The paper presents the measurements of the shock waves intensities, generated by soft X-radiation in Al and Pb targets. The soft X-radiation was induced by the dynamic compression and heating of the plasma in the cylindrical Z-pinch geometry in the ANGARA-5-1 installation. 1D computer simulation of shock wave generation were performed with realistic EOS and energy transfer models. {copyright} {ital 1996 American Institute of Physics.}

  6. Mechanochemistry for shock wave energy dissipation

    NASA Astrophysics Data System (ADS)

    Shaw, William L.; Ren, Yi; Moore, Jeffrey S.; Dlott, Dana D.

    2017-01-01

    Using a laser-driven flyer-plate apparatus to launch 75 μm thick Al flyers up to 2.8 km/s, we developed a technique for detecting the attenuation of shock waves by mechanically-driven chemical reactions. The attenuating sample was spread on an ultrathin Au mirror deposited onto a glass window having a known Hugoniot. As shock energy exited the sample and passed through the mirror, into the glass, photonic Doppler velocimetry monitored the velocity profile of the ultrathin mirror. Knowing the window Hugoniot, the velocity profile could be quantitatively converted into a shock energy flux or fluence. The flux gave the temporal profile of the shock front, and showed how the shock front was reshaped by passing through the dissipative medium. The fluence, the time-integrated flux, showed how much shock energy was transmitted through the sample. Samples consisted of microgram quantities of carefully engineered organic compounds selected for their potential to undergo negative-volume chemistry. Post mortem analytical methods were used to confirm that shock dissipation was associated with shock-induced chemical reactions.

  7. Propagation of shock waves through clouds

    NASA Astrophysics Data System (ADS)

    Zhou, Xin Xin

    1990-10-01

    The behavior of a shock wave propagating into a cloud consisting of an inert gas, water vapor and water droplets was investigated. This has particular application to sonic bangs propagating in the atmosphere. The finite different method of MacCormack is extended to solve the one and two dimensional, two phase flow problems in which mass, momentum and energy transfers are included. The FCT (Fluid Corrected Transport) technique developed by Boris and Book was used in the basic numerical scheme as a powerful corrective procedure. The results for the transmitted shock waves propagating in a one dimensional, semi infinite cloud obtained by the finite difference approach are in good agreement with previous results by Kao using the method characteristics. The advantage of the finite difference method is its adaptability to two and three dimensional problems. Shock wave propagation through a finite cloud and into an expansion with a 90 degree corner was investigated. It was found that the transfer processes between the two phases in two dimensional flow are much more complicated than in the one dimensional flow cases. This is mainly due to the vortex and expansion wave generated at the corner. In the case considered, further complications were generated by the reflected shock wave from the floor. Good agreement with experiment was found for one phase flow but experimental data for the two phase case is not yet available to validate the two phase calculations.

  8. Amorphization and nanocrystallization of silcon under shock compression

    SciTech Connect

    Remington, B. A.; Wehrenberg, C. E.; Zhao, S.; Hahn, E. N.; Kad, B.; Bringa, E. M.; Meyers, M. A.

    2015-11-06

    High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon unveiled remarkable structural changes above a pressure threshold. Two distinct amorphous regions were identified: (a) a bulk amorphous layer close to the surface and (b) amorphous bands initially aligned with {111} slip planes. Further increase of the laser energy leads to the re-crystallization of amorphous silicon into nanocrystals with high concentration of nano-twins. This amorphization is produced by the combined effect of high magnitude hydrostatic and shear stresses under dynamic shock compression. Shock-induced defects play a very important role in the onset of amorphization. Calculations of the free energy changes with pressure and shear, using the Patel-Cohen methodology, are in agreement with the experimental results. Molecular dynamics simulation corroborates the amorphization, showing that it is initiated by the nucleation and propagation of partial dislocations. As a result, the nucleation of amorphization is analyzed qualitatively by classical nucleation theory.

  9. Frequency shift measurement in shock-compressed materials

    DOEpatents

    Moore, David S.; Schmidt, Stephen C.

    1985-01-01

    A method for determining molecular vibrational frequencies in shock-compressed transparent materials. A single laser beam pulse is directed into a sample material while the material is shock-compressed from a direction opposite that of the incident laser beam. A Stokes beam produced by stimulated Raman scattering is emitted back along the path of the incident laser beam, that is, in the opposite direction to that of the incident laser beam. The Stokes beam is separated from the incident beam and its frequency measured. The difference in frequency between the Stokes beam and the incident beam is representative of the characteristic frequency of the Raman active mode of the sample. Both the incident beam and the Stokes beam pass perpendicularly through the shock front advancing through the sample, thereby minimizing adverse effects of refraction.

  10. Biological effects of shock waves: lung hemorrhage by shock waves in dogs--pressure dependence.

    PubMed

    Delius, M; Enders, G; Heine, G; Stark, J; Remberger, K; Brendel, W

    1987-02-01

    The most serious side effect observed during the destruction of gallstones by shock waves in dogs was lung bleeding. To determine the conditions leading to lung damage, pressure probes were implanted into dogs between the lung and the diaphragm. The distance between the lung and the focal point of the pressure field was determined at which 1000 shock waves caused no more lung hemorrhage. On the long axis it is greater than 15 cm and perpendicular to the long axis it is 4 cm. Shock wave pressures over 2 MPa could be administered safely, whereas a pressure of 10 MPa caused bleedings in beagles, but probably not in boxers.

  11. Acoustic field of a ballistic shock wave therapy device.

    PubMed

    Cleveland, Robin O; Chitnis, Parag V; McClure, Scott R

    2007-08-01

    Shock wave therapy (SWT) refers to the use of focused shock waves for treatment of musculoskeletal indications including plantar fascitis and dystrophic mineralization of tendons and joint capsules. Measurements were made of a SWT device that uses a ballistic source. The ballistic source consists of a handpiece within which compressed air (1-4 bar) is used to fire a projectile that strikes a metal applicator placed on the skin. The projectile generates stress waves in the applicator that transmit as pressure waves into tissue. The acoustic fields from two applicators were measured: one applicator was 15 mm in diameter and the surface slightly convex and the second was 12 mm in diameter the surface was concave. Measurements were made in a water tank and both applicators generated a similar pressure pulse consisting of a rectangular positive phase (4 micros duration and up to 8 MPa peak pressure) followed by a predominantly negative tail (duration of 20 micros and peak negative pressure of -6 MPa), with many oscillations. The rise times of the waveforms were around 1 micros and were shown to be too long for the pulses to be considered shock waves. Measurements of the field indicated that region of high pressure was restricted to the near-field (20-40 mm) of the source and was consistent with the Rayleigh distance. The measured acoustic field did not display focusing supported by calculations, which demonstrated that the radius of curvature of the concave surface was too large to effect a focusing gain. Other SWT devices use electrohydraulic, electromagnetic and piezoelectric sources that do result in focused shock waves. This difference in the acoustic fields means there is potentially a significant mechanistic difference between a ballistic source and other SWT devices.

  12. A Study of the Shock Sensitivity of PBX 9501 Damaged by Compressive Loading

    NASA Astrophysics Data System (ADS)

    Thompson, Darla; Gustavsen, Richard; Hooks, Daniel; Peterson, Paul; Deluca, Racci; Stahl, David; Hagelberg, Stephanie; Alcon, Robert

    2007-06-01

    We have studied the effects of damage caused by compressive loading on the shock sensitivity of the plastic bonded explosive PBX 9501. PBX 9501 consists of 95 wt. % HMX (C4H8N8O8) and 5 wt. % Nitroplasticized Estane binder. The binder is a mixture of 49 wt. % Estane^5703 (BF Goodrich), 49 wt. % Nitroplasticizer (a 50/50 eutectic mixture of bis(2,2-dinitropropyl)formal and bis(2,2 dinitropropyl)acetal), and 2 wt. % Irganox^ 1010 stabilizer. PBX 9501 cubes, 25.4 mm on a side, were subjected to various uniaxial compressive loads in an Instron machine. After loading, 3.5 mm thick slices were taken from the center of each cube. These slices were then subjected to nearly identical 35 kbar shocks. Transmitted shock wave profiles were measured using interface velocimetry (VISAR). Comparison of shock wave growth is a measure of shock sensitivity. Results on four specimens are being analyzed relative to previous baseline data on PBX 9501 at various pressed densities, to determine if the response of damaged material is due to factors other than simple density changes. (LA-UR 07-1206)

  13. Burnett-Cattaneo continuum theory for shock waves

    NASA Astrophysics Data System (ADS)

    Holian, Brad Lee; Mareschal, Michel; Ravelo, R.

    2012-03-01

    We model strong shockwave propagation, both in the ideal gas and in the dense Lennard- Jones fluid, using a refinement of earlier work, which accounts for the cold compression in the early stages of the shock rise by a nonlinear, Burnett-like, strain-rate dependence of the thermal conductivity, and relaxation of kinetic temperature components on the hot, compressed side of the shock front. The relaxation of the disequilibrium among the three components of the kinetic temperature, namely, the difference between the component in the direction of a planar shock wave and those in the transverse directions, particularly in the region near the shock front, is accomplished at a much more quantitative level by the first-ever rigorous application of the Cattaneo-Maxwell relaxation equation to a reference solution, namely, the steady shockwave solution of linear Navier- Stokes-Fourier theory, along with the nonlinear Burnett heat-flux term. Our new continuum theory is in nearly quantitative agreement with non-equilibrium molecular-dynamics simulations under strong shockwave conditions, using relaxation parameters obtained from the reference solution.

  14. Burnett-Cattaneo continuum theory for shock waves

    NASA Astrophysics Data System (ADS)

    Holian, Brad Lee; Mareschal, Michel; Ravelo, Ramon

    2011-06-01

    We model strong shockwave propagation, both in the ideal gas and in the dense Lennard-Jones fluid, using a refinement of earlier work, which accounts for the cold compression in the early stages of the shock rise by a nonlinear, Burnett-like, strain-rate dependence of the thermal conductivity, and relaxation of kinetic temperature components on the hot, compressed side of the shock front. The relaxation of the disequilibrium among the three components of the kinetic temperature, namely, the difference between the component in the direction of a planar shock wave and those in the transverse directions, particularly in the region near the shock front, is accomplished at a much more quantitative level by the first-ever rigorous application of the Cattaneo-Maxwell relaxation equation to a reference solution, namely, the steady shockwave solution of linear Navier-Stokes-Fourier theory, along with the nonlinear Burnett heat-flux term. Our new continuum theory is in nearly quantitative agreement with non-equilibrium molecular-dynamics simulations under strong shockwave conditions, using relaxation parameters obtained from the reference solution.

  15. Hydrodynamic simulations of gaseous Argon shock compression experiments

    NASA Astrophysics Data System (ADS)

    Garcia, Daniel B.; Dattelbaum, Dana M.; Goodwin, Peter M.; Sheffield, Stephen A.; Morris, John S.; Gustavsen, Richard L.; Burkett, Michael W.

    2017-01-01

    The lack of published Ar gas shock data motivated an evaluation of the Ar Equation of State (EOS) in gas phase initial density regimes. In particular, these regimes include initial pressures in the range of 13.8 - 34.5 bar (0.025 - 0.056 g/ cm3) and initial shock velocities around 0.2 cm/μs. The objective of the numerical evaluation was to develop a physical understanding of the EOS behavior of shocked and subsequently multiply re-shocked Ar gas through Pagosa numerical simulations utilizing the SESAME equation of state. Pagosa is a Los Alamos National Laboratory 2-D and 3-D Eulerian continuum dynamics code capable of modeling high velocity compressible flow with multiple materials. The approach involved the use of gas gun experiments to evaluate the shock and multiple re-shock behavior of pressurized Ar gas to validate Pagosa simulations and the SESAME EOS. Additionally, the diagnostic capability within the experiments allowed for the EOS to be fully constrained with measured shock velocity, particle velocity and temperature. The simulations demonstrate excellent agreement with the experiments in the shock velocity/particle velocity space, and reasonable comparisons for the ionization temperatures.

  16. Visualizing structural dynamics of aluminum and iron under laser shock compression with time-resolved X-ray diffraction method

    NASA Astrophysics Data System (ADS)

    Takagi, S.; Ichiyanagi, K.; Fukaya, R.; Syunsuke, N.; Kawai, N.; Kazutaka, N.; Kyono, A.; Nobumasa, F.; Adachi, S. I.

    2016-12-01

    Understanding the characterization of Earth's materials under shock compression is indispensable to comprehend the dynamics of the Earth such as fault movement in the crust, deep earthquake in the mantle, and meteorite collision. We investigated structural dynamics of aluminum and iron polycrystalline materials under laser shock compression by using the nanosecond time-resolved X-ray diffraction (TR-XRD) with the high power Nd:Glass laser system installed at the NW14A beamline, Photon Factory Advanced Ring (PF-AR), High Energy Accelerator Research Organization (KEK), Japan. The Nd:Glass laser system as the shock wave device was composed of the oscillator system (Q-switch Nd:YAG laser) and three stages amplifiers. The pulse width, wavelength, repetition rate, and energy of the Nd:Glass laser were 12 ns, 1064 nm, 9.46 Hz, and 16 J/pulse, respectively. The laser system was synchronized with the rf master clock of the PF-AR. A monochromatic X-ray with the energy of 15.68 keV and pulse width of 100 ps was employed as a probe source. We utilized a polycrystalline aluminum foil with the thickness of 100 mm and an iron foil of 20 mm as target materials. TR-XRD patterns of aluminum exhibited continuous structural change during the shock-wave loading up to 14.19 ns (Fig.1). No phase transition was observed during the compression. The shock compression pressure was estimated to be reached at least 10 GPa. The iron, on the other hand, underwent the α (bcc)-ɛ (hcp) phase transition at 13 GPa. In this presentation, we will discuss the details of structural dynamics under shock compression, and report the shock compressed crystal structures analyzed by XRD patterns and shock wave profiles.

  17. Experimental Plans for Subsystems of a Shock Wave Driven Gas Core Reactor

    NASA Technical Reports Server (NTRS)

    Kazeminezhad, F.; Anghai, S.

    2008-01-01

    This Contractor Report proposes a number of plans for experiments on subsystems of a shock wave driven pulsed magnetic induction gas core reactor (PMI-GCR, or PMD-GCR pulsed magnet driven gas core reactor). Computer models of shock generation and collision in a large-scale PMI-GCR shock tube have been performed. Based upon the simulation results a number of issues arose that can only be addressed adequately by capturing experimental data on high pressure (approx.1 atmosphere or greater) partial plasma shock wave effects in large bore shock tubes ( 10 cm radius). There are three main subsystems that are of immediate interest (for appraisal of the concept viability). These are (1) the shock generation in a high pressure gas using either a plasma thruster or pulsed high magnetic field, (2) collision of MHD or gas dynamic shocks, their interaction time, and collision pile-up region thickness, and (3) magnetic flux compression power generation (not included here).

  18. Shock Waves and the Origin of Life

    DTIC Science & Technology

    1977-01-01

    The thunder shock-wave can be approximated by the so-called cyl- indrical ’blast wave theory ’ (22, 24) for a single lightning stroke. The ’ theory ’ is... theory can be finally tested. Historically, the question of how life originated received the answer which was contemporarily available within the...Origin of Species," that the theory of spontaneous gpneration was finally aisproved by Louis Pasteur. In a series of exceptiorally lucid experiments

  19. Plasma waves downstream of weak collisionless shocks

    NASA Technical Reports Server (NTRS)

    Coroniti, F. V.; Greenstadt, E. W.; Moses, S. L.; Smith, E. J.; Tsurutani, B. T.

    1993-01-01

    In September 1983 the International Sun Earth Explorer 3 (ISEE 3) International Cometary Explorer (ICE) spacecraft made a long traversal of the distant dawnside flank region of the Earth's magnetosphere and had many encounters with the low Mach number bow shock. These weak shocks excite plasma wave electric field turbulence with amplitudes comparable to those detected in the much stronger bow shock near the nose region. Downstream of quasi-perpendicular (quasi-parallel) shocks, the E field spectra exhibit a strong peak (plateau) at midfrequencies (1 - 3 kHz); the plateau shape is produced by a low-frequency (100 - 300 Hz) emission which is more intense behind downstream of two quasi-perpendicular shocks show that the low frequency signals are polarized parallel to the magnetic field, whereas the midfrequency emissions are unpolarized or only weakly polarized. A new high frequency (10 - 30 kHz) emission which is above the maximum Doppler shift exhibit a distinct peak at high frequencies; this peak is often blurred by the large amplitude fluctuations of the midfrequency waves. The high-frequency component is strongly polarized along the magnetic field and varies independently of the lower-frequency waves.

  20. Shock compressing diamond to a conducting fluid.

    PubMed

    Bradley, D K; Eggert, J H; Hicks, D G; Celliers, P M; Moon, S J; Cauble, R C; Collins, G W

    2004-11-05

    Laser generated shock reflectance data show that diamond undergoes a continuous transition from optically absorbing to reflecting between Hugoniot pressures 600

  1. Shock Compressing Diamond to a Conducting Fluid

    SciTech Connect

    Bradley, D K; Eggert, J H; Hicks, D G; Celliers, P M; Moon, S J; Cauble, R C; Collins, G W

    2004-07-29

    Laser generated shock reflectance data show that diamond undergoes a continuous transition from optically absorbing to reflecting between Hugoniot pressures 600

  2. State of the art extracorporeal shock wave lithotripsy

    SciTech Connect

    Kandel, L.B. ); Harrison, L.H.; McCullough, D.L. )

    1987-01-01

    This book contains 16 chapters. Some of the topics that are covered are: Extracorporeal Shock Wave Lithotripsy Development; Laser-Generated Extracorporeal Shock Wave Lithotripter; Radiation Exposure during ESWL; Caliceal Calculi; and Pediatric ESWL.

  3. 21 CFR 876.5990 - Extracorporeal shock wave lithotripter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... focuses ultrasonic shock waves into the body to noninvasively fragment urinary calculi within the kidney... Notifications (510(k)'s) for Extracorporeal Shock Wave Lithotripters Indicated for the Fragmentation of...

  4. 21 CFR 876.5990 - Extracorporeal shock wave lithotripter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... focuses ultrasonic shock waves into the body to noninvasively fragment urinary calculi within the kidney... Notifications (510(k)'s) for Extracorporeal Shock Wave Lithotripters Indicated for the Fragmentation of...

  5. 21 CFR 876.5990 - Extracorporeal shock wave lithotripter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... focuses ultrasonic shock waves into the body to noninvasively fragment urinary calculi within the kidney... Notifications (510(k)'s) for Extracorporeal Shock Wave Lithotripters Indicated for the Fragmentation of...

  6. Multiple scales of shock waves in dissipative laminate materials.

    PubMed

    Franco Navarro, Pedro; Benson, David J; Nesterenko, Vitali F

    2016-09-01

    The shock waves generated by a plate impact are numerically investigated in Al-W laminates with different mesostructures. The main characteristic time scales (and the corresponding spatial scales) related to the formation of the stationary shock are identified: the duration (width) of the leading front, the time (distance) from the impact required to establish a stationary profile, and the shock front width, identified as a time span (distance) from the initial state to the final quasiequilibrium state. It is demonstrated that the width of the leading front and the maximum strain rates are determined by the dispersive and the nonlinear parameters of the laminate and not by the dissipation, as is the case for uniform solids. The characteristic spatial scale of the leading front is related to the spatial scale observed on solitarylike waves, which are satisfactorily described by the Korteweg-de Vries (KdV) approximation, as well as the speed of the wave and the ratio of maximum to final strain. The dissipation affects the width of the transition distance (shock front width) where multiple loading-unloading cycles bring the laminate into the final quasiequilibrium state. This spatial scale is of the same order of magnitude as the distance to form stationary shock wave. The period of fast decaying oscillations is well described by the KdV approach and scales linearly with the cell size. The rate of the decay of the oscillations in the numerical calculations does not scale with the square of the cell size as expected from the dissipative KdV approach that assumes a constant viscosity. This is due to the different mechanisms of dissipation in high-amplitude compression pulses.

  7. Shock compression and release of a-axis magnesium single crystals: Anisotropy and time dependent inelastic response

    NASA Astrophysics Data System (ADS)

    Renganathan, P.; Winey, J. M.; Gupta, Y. M.

    2017-01-01

    To gain insight into inelastic deformation mechanisms for shocked hexagonal close-packed (hcp) metals, particularly the role of crystal anisotropy, magnesium (Mg) single crystals were subjected to shock compression and release along the a-axis to 3.0 and 4.8 GPa elastic impact stresses. Wave profiles measured at several thicknesses, using laser interferometry, show a sharply peaked elastic wave followed by the plastic wave. Additionally, a smooth and featureless release wave is observed following peak compression. When compared with wave profiles measured previously for c-axis Mg [Winey et al., J. Appl. Phys. 117, 105903 (2015)], the elastic wave amplitudes for a-axis Mg are lower for the same propagation distance, and less attenuation of elastic wave amplitude is observed for a given peak stress. The featureless release wave for a-axis Mg is in marked contrast to the structured features observed for c-axis unloading. Numerical simulations, using a time-dependent anisotropic modeling framework, showed that the wave profiles calculated using prismatic slip or (10 1 ¯ 2 ) twinning, individually, do not match the measured compression profiles for a-axis Mg. However, a combination of slip and twinning provides a good overall match to the measured compression profiles. In contrast to compression, prismatic slip alone provides a reasonable match to the measured release wave profiles; (10 1 ¯ 2 ) twinning due to its uni-directionality is not activated during release. The experimental results and wave profile simulations for a-axis Mg presented here are quite different from the previously published c-axis results, demonstrating the important role of crystal anisotropy in the time-dependent inelastic deformation of Mg single crystals under shock compression and release.

  8. Shock compression and release of a-axis magnesium single crystals: Anisotropy and time dependent inelastic response

    DOE PAGES

    Renganathan, P.; Winey, J. M.; Gupta, Y. M.

    2017-01-19

    Here, to gain insight into inelastic deformation mechanisms for shocked hexagonal close-packed (hcp) metals, particularly the role of crystal anisotropy, magnesium (Mg) single crystals were subjected to shock compression and release along the a-axis to 3.0 and 4.8 GPa elastic impact stresses. Wave profiles measured at several thicknesses, using laser interferometry, show a sharply peaked elastic wave followed by the plastic wave. Additionally, a smooth and featureless release wave is observed following peak compression. When compared to wave profiles measured previously for c-axis Mg, the elastic wave amplitudes for a-axis Mg are lower for the same propagation distance, and less attenuation of elastic wave amplitude is observed for a given peak stress. The featureless release wave for a-axis Mg is in marked contrast to the structured features observed for c-axis unloading. Numerical simulations, using a time-dependent anisotropic modeling framework, showed that the wave profiles calculated using prismatic slip or (10more » $$\\bar{1}$$2) twinning, individually, do not match the measured compression profiles for a-axis Mg. However, a combination of slip and twinning provides a good overall match to the measured compression profiles. In contrast to compression,prismatic slip alone provides a reasonable match to the measured release wave profiles; (10$$\\bar{1}$$2) twinning due to its uni-directionality is not activated during release. The experimental results and wave profile simulations for a-axis Mg presented here are quite different from the previously published c-axis results, demonstrating the important role of crystal anisotropy on the time-dependent inelastic deformation of Mg single crystals under shock compression and release.« less

  9. Thin Foil Acceleration Method for Measuring the Unloading Isentropes of Shock-Compressed Matter

    SciTech Connect

    Asay, J.R.; Chhabildas, L.C.; Fortov, V.E.; Kanel, G.I.; Khishchenko, K.V.; Lomonosov, I.V.; Mehlhorn, T.; Razorenov, S.V.; Utkin, A.V.

    1999-07-21

    This work has been performed as part of the search for possible ways to utilize the capabilities of laser and particle beams techniques in shock wave and equation of state physics. The peculiarity of these techniques is that we have to deal with micron-thick targets and not well reproducible incident shock wave parameters, so all measurements should be of a high resolution and be done in one shot. Besides the Hugoniots, the experimental basis for creating the equations of state includes isentropes corresponding to unloading of shock-compressed matter. Experimental isentrope data are most important in the region of vaporization. With guns or explosive facilities, the unloading isentrope is recovered from a series of experiments where the shock wave parameters in plates of standard low-impedance materials placed behind the sample are measured [1,2]. The specific internal energy and specific volume are calculated from the measured p(u) release curve which corresponds to the Riemann integral. This way is not quite suitable for experiments with beam techniques where the incident shock waves are not well reproducible. The thick foil method [3] provides a few experimental points on the isentrope in one shot. When a higher shock impedance foil is placed on the surface of the material studied, the release phase occurs by steps, whose durations correspond to that for the shock wave to go back and forth in the foil. The velocity during the different steps, connected with the knowledge of the Hugoniot of the foil, allows us to determine a few points on the isentropic unloading curve. However, the method becomes insensitive when the low pressure range of vaporization is reached in the course of the unloading. The isentrope in this region can be measured by recording the smooth acceleration of a thin witness plate foil. With the mass of the foil known, measurements of the foil acceleration will give us the vapor pressure.

  10. Passive control of unsteady condensation shock wave

    NASA Astrophysics Data System (ADS)

    Setoguchi, Toshiaki; Matsuo, Shigeru; Shimamoto, Katsumi; Yasugi, Shinichi; Yu, Shen

    2000-12-01

    A rapid expansion of moist air or steam in a supersonic nozzle gives rise to nonequilibrium condensation phenomena. Thereby, if the heat released by condensation of water vapour exceeds a certain quantity, the flow will become unstable and periodic flow oscillations of the unsteady condensation shock wave will occur. For the passive control of shock-boundary layer interaction using the porous wall with a plenum underneath, many papers have been presented on the application of the technique to transonic airfoil flows. In this paper, the passive technique is applied to three types of oscillations of the unsteady condensation shock wave generated in a supersonic nozzle in order to suppress the unsteady behavior. As a result, the effects of number of slits and length of cavity on the aspect of flow field have been clarified numerically using a 3rd-order MUSCL type TVD finite-difference scheme with a second-order fractional-step for time integration.

  11. Using phase contrast imaging to measure the properties of shock compressed aerogel

    NASA Astrophysics Data System (ADS)

    Hawreliak, James; Erskine, Dave; Schropp, Andres; Galtier, Eric C.; Heimann, Phil

    2017-01-01

    The Hugoniot states of low density materials, such as silica aerogel, are used in high energy density physics research because they can achieve a range of high temperature and pressure states through shock compression. The shock properties of 100mg/cc silica aerogel were studied at the Materials in Extreme Conditions end station using x-ray phase contrast imaging of spherically expanding shock waves. The shockwaves were generated by focusing a high power 532nm laser to a 50μm focal spot on a thin aluminum ablator. The shock speed was measured in separate experiments using line-VISAR measurements from the reflecting shock front. The relative timing between the x-ray probe and the optical laser pump was varied so x-ray PCI images were taken at pressures between 10GPa and 30GPa. Modeling the compression of the foam in the strong shock limit uses a Gruneisen parameter of 0.49 to fit the data rather than a value of 0.66 that would correspond to a plasma state.

  12. Shock wave driven by a phased implosion

    SciTech Connect

    Menikoff, R.; Lackner, K.S.; Johnson, N.L.; Colgate, S.A.; Hyman, J.M. ); Miranda, G.A. )

    1991-01-01

    In this paper the theory of an axially phased radial implosion of a channel is developed. When the phase velocity of the implosion exceeds the sound velocity inside the channel, a planar shock wave traveling along the channel axis can develop. For the energy of the implosion system in the appropriate range, the theory predicts a stable steady-state flow configuration. The effect of the phased implosion is for the channel wall to form a nozzle that travels along the channel axis. The flow behind the axial shock is well described by the equations for nozzle flow with an additional dynamical degree of freedom for the shape of the wall. Experiments presented here verify the theoretical predictions. The numerical simulations show the formation of the axial shock during start-up and the approach to steady state to be in good agreement with experiment and theory. A potential application of the axially phased implosion is the design of a super shock tube.

  13. The Collisions of Chondrules Behind Shock Waves

    NASA Technical Reports Server (NTRS)

    Ciesla, F. J.; Hood, L. L.

    2004-01-01

    One of the reasons that the mechanism(s) responsible for the formation of chondrules has remained so elusive is that each proposed mechanism must be able to explain a large number of features observed in chondrules. Most models of chondrule formation focus on matching the expected thermal histories of chondrules: rapid heating followed by cooling during crystallization at rates between approx. 10-1000 K/hr [1], and references therein]. Thus far, only models for large shock waves in the solar nebula have quantitatively shown that the thermal evolution of millimeter-sized particles in the nebula can match these inferred thermal histories [2-4]. While this is a positive step for the shock wave model, further testing is needed to see if other properties of chondrules can be explained in the context of this model. One area of interest is understanding the collisional evolution of chondrules after they encounter a shock wave. These collisions could lead to sticking, destruction, or bouncing. Here we focus on understanding what conditions are needed for these different outcomes to occur and try to reconcile the seemingly contradictory conclusions reached by studies of compound chondrule formation and chondrule destruction by collisions behind a shock wave.

  14. Uncovering the Secret of Shock Wave Lithotripsy

    NASA Astrophysics Data System (ADS)

    Zhong, P.

    Shock wave lithotripsy (SWL) is an engineering innovation that has revolutionized the treatment of kidney stone disease since the early 1980s [1] - [3]. Today, SWL is the first-line therapy for millions of patients worldwide with renal and upper urinary stones [3, 4].

  15. Shock wave absorber having a deformable liner

    DOEpatents

    Youngdahl, C.K.; Wiedermann, A.H.; Shin, Y.W.; Kot, C.A.; Ockert, C.E.

    1983-08-26

    This invention discloses a shock wave absorber for a piping system carrying liquid. The absorber has a plastically deformable liner defining the normal flow boundary for an axial segment of the piping system, and a nondeformable housing is spaced outwardly from the liner so as to define a gas-tight space therebetween. The flow capacity of the liner generally corresponds to the flow capacity of the piping system line, but the liner has a noncircular cross section and extends axially of the piping system line a distance between one and twenty times the diameter thereof. Gas pressurizes the gas-tight space equal to the normal liquid pressure in the piping system. The liner has sufficient structural capacity to withstand between one and one-half and two times this normal liquid pressures; but at greater pressures it begins to plastically deform initially with respect to shape to a more circular cross section, and then with respect to material extension by circumferentially stretching the wall of the liner. A high energy shock wave passing through the liner thus plastically deforms the liner radially into the gas space and progressively also as needed in the axial direction of the shock wave to minimize transmission of the shock wave beyond the absorber.

  16. Finite element modelling of radial shock wave therapy for chronic plantar fasciitis.

    PubMed

    Alkhamaali, Zaied K; Crocombe, Andrew D; Solan, Matthew C; Cirovic, Srdjan

    2016-01-01

    Therapeutic use of high-amplitude pressure waves, or shock wave therapy (SWT), is emerging as a popular method for treating musculoskeletal disorders. However, the mechanism(s) through which this technique promotes healing are unclear. Finite element models of a shock wave source and the foot were constructed to gain a better understanding of the mechanical stimuli that SWT produces in the context of plantar fasciitis treatment. The model of the shock wave source was based on the geometry of an actual radial shock wave device, in which pressure waves are generated through the collision of two metallic objects: a projectile and an applicator. The foot model was based on the geometry reconstructed from magnetic resonance images of a volunteer and it comprised bones, cartilage, soft tissue, plantar fascia, and Achilles tendon. Dynamic simulations were conducted of a single and of two successive shock wave pulses administered to the foot. The collision between the projectile and the applicator resulted in a stress wave in the applicator. This wave was transmitted into the soft tissue in the form of compression-rarefaction pressure waves with an amplitude of the order of several MPa. The negative pressure at the plantar fascia reached values of over 1.5 MPa, which could be sufficient to generate cavitation in the tissue. The results also show that multiple shock wave pulses may have a cumulative effect in terms of strain energy accumulation in the foot.

  17. Interferometric data for a shock-wave/boundary-layer interaction

    NASA Technical Reports Server (NTRS)

    Dunagan, Stephen E.; Brown, James L.; Miles, John B.

    1986-01-01

    An experimental study of the axisymmetric shock-wave / boundary-layer strong interaction flow generated in the vicinity of a cylinder-cone intersection was conducted. The study data are useful in the documentation and understanding of compressible turbulent strong interaction flows, and are part of a more general effort to improve turbulence modeling for compressible two- and three-dimensional strong viscous/inviscid interactions. The nominal free stream Mach number was 2.85. Tunnel total pressures of 1.7 and 3.4 atm provided Reynolds number values of 18 x 10(6) and 36 x 10(6) based on model length. Three cone angles were studied giving negligible, incipient, and large scale flow separation. The initial cylinder boundary layer upstream of the interaction had a thickness of 1.0 cm. The subsonic layer of the cylinder boundary layer was quite thin, and in all cases, the shock wave penetrated a significant portion of the boundary layer. Owing to the thickness of the cylinder boundary layer, considerable structural detail was resolved for the three shock-wave / boundary-layer interaction cases considered. The primary emphasis was on the application of the holographic interferometry technique. The density field was deduced from an interferometric analysis based on the Able transform. Supporting data were obtained using a 2-D laser velocimeter, as well as mean wall pressure and oil flow measurements. The attached flow case was observed to be steady, while the separated cases exhibited shock unsteadiness. Comparisons with Navier-Stokes computations using a two-equation turbulence model are presented.

  18. Shock compression of quartz and aluminum powder mixtures

    SciTech Connect

    Joshi, V.S.; Thadhani, N.N.; Graham, R.A.; Holman, G.T. Jr.

    1995-11-01

    The authors report about the shock-compression response of highly porous (55% and 65% dense) mixtures of 4Al + 3SiO{sub 2} powders having shock-induced phase transitions and chemical reactions. Shock recovery experiments were performed using the CETR/Sawaoka plate-impact system (P = 40 to 100 GPa) and the Sandia Momma Bear A Comp B fixture (P = 22 to 45 GPa). The recovered compacts contained the high pressure stishovite phase, products of chemical reaction, as well as unreacted constituents. The reaction products formed included Al{sub 2}O{sub 3} metallic Si (ambient and high pressure phases), SiAl intermetallic, and kyanite (Al{sub 2}SiO{sub 5}). The shock-induced chemical reaction in 4Al + 3SiO{sub 2} powder mixtures, appears to have been accompanied (or assisted) by the formation of stishovite, a high pressure phase of quartz.

  19. The α-γ-ɛ triple point and phase boundaries of iron under shock compression

    NASA Astrophysics Data System (ADS)

    Li, Jun; Wu, Qiang; Xue, Tao; Geng, Huayun; Yu, Jidong; Jin, Ke; Li, Jiabo; Tan, Ye; Xi, Feng

    2017-07-01

    The phase transition of iron under shock compression has attracted much attention in recent decades because of its importance in fields such as condensed matter physics, geophysics, and metallurgy. At room temperature, the transition of iron from the α-phase (bcc) to the ɛ-phase (hpc) occurs at a stress of 13 GPa. At high temperature, a triple point followed by transformation to the γ-phase (fcc) is expected. However, the details of the high-temperature phase transitions of iron are still under debate. Here, we investigate the phase-transition behavior of polycrystalline iron under compression from room temperature to 820 K. The results show that the shock-induced phase transition is determined unequivocally from the measured three-wave-structure profiles, which clearly consist of an elastic wave, a plastic wave, and a phase-transition wave. The phase transition is temperature-dependent, with an average rate Δσtr/ΔT of -6.91 MPa/K below 700 K and -34.7 MPa/K at higher temperatures. The shock α-ɛ and α-γ phase boundaries intersect at 10.6 ± 0.53 GPa and 763 K, which agrees with the α-ɛ-γ triple point from early shock wave experiments and recent laser-heated diamond-anvil cell resistivity and in situ X-ray diffraction data but disagrees with the shock pressure-temperature phase diagram reported in 2009 by Zaretsky [J. Appl. Phys. 106, 023510 (2009)].

  20. Imaging Shock Waves in Diamond with Both High Temporal and Spatial Resolution at an XFEL

    PubMed Central

    Schropp, Andreas; Hoppe, Robert; Meier, Vivienne; Patommel, Jens; Seiboth, Frank; Ping, Yuan; Hicks, Damien G.; Beckwith, Martha A.; Collins, Gilbert W.; Higginbotham, Andrew; Wark, Justin S.; Lee, Hae Ja; Nagler, Bob; Galtier, Eric C.; Arnold, Brice; Zastrau, Ulf; Hastings, Jerome B.; Schroer, Christian G.

    2015-01-01

    The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range, and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width, and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions. PMID:26086176

  1. Imaging shock waves in diamond with both high temporal and spatial resolution at an XFEL

    SciTech Connect

    Schropp, Andreas; Hoppe, Robert; Meier, Vivienne; Patommel, Jens; Seiboth, Frank; Ping, Yuan; Hicks, Damien G.; Beckwith, Martha A.; Collins, Gilbert W.; Higginbotham, Andrew; Wark, Justin S.; Lee, Hae Ja; Nagler, Bob; Galtier, Eric C.; Arnold, Brice; Zastrau, Ulf; Hastings, Jerome B.; Schroer, Christian G.

    2015-06-18

    The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range, and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width, and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions.

  2. Imaging Shock Waves in Diamond with Both High Temporal and Spatial Resolution at an XFEL.

    PubMed

    Schropp, Andreas; Hoppe, Robert; Meier, Vivienne; Patommel, Jens; Seiboth, Frank; Ping, Yuan; Hicks, Damien G; Beckwith, Martha A; Collins, Gilbert W; Higginbotham, Andrew; Wark, Justin S; Lee, Hae Ja; Nagler, Bob; Galtier, Eric C; Arnold, Brice; Zastrau, Ulf; Hastings, Jerome B; Schroer, Christian G

    2015-06-18

    The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range, and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width, and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions.

  3. Shock wave propagation in glow discharges

    NASA Astrophysics Data System (ADS)

    Ganguly, B. N.

    1998-10-01

    The modification of acoustic shock wave propagation characteristics in a 25 cm long positive column low pressure (10 to 50 Torr), low current density (2 to 10 mA/cm^2) argon and N2 dc discharges have been measured by laser beam deflection technique. The simultaneous multi point shock velocity, dispersion and damping have been measured both inside and outside the glow discharge region. The local shock velocity is found to increase with the increased propagation path length through the discharge; for Mach number greater than 1.7 the upstream velocity exceeded the downstream velocity in contrast to the opposite behavior in neutral gas. The damping and dispersion are also dependent on the propagation distance. The recovery of the shock dispersion and damping in the post discharge region, for a given discharge condition, are functions of the initial Mach number. The optical measurement of the wall and the gas (rotational) temperatures suggest the observed shock features can not be solely explained by the gas heating in a self sustained discharge. The results are similar for both Ar and N2 discharges showing that vibrational excitation and relaxation are not essential^1. The explanation of the observed weak shock propagation properties in a glow discharge appears to require long range cooperative interactions that enhance heavy particle collisional energy transfer rates for the measured discharge conditions. Unlike collisional shock wave propagation in highly ionized plasmas^2,3, the exact energy coupling mechanism between the nonequilibrium weakly ionized plasma and shock is not understood. 1. A.I. Osipov and A.V. Uvarov, Sov. Phys. Usp. 35, 903 (1992) and other references there in. 2. M. Casanova, O. Larroche and J-P Matte, Phys. Rev. Lett. 67, 2143 (1991). 3. M.C.M. van de Sanden, R. van den Bercken and D.C. Schram, Plasma Sources Sci.Technol. 3, 511 (1994).

  4. Wave energy devices with compressible volumes.

    PubMed

    Kurniawan, Adi; Greaves, Deborah; Chaplin, John

    2014-12-08

    We present an analysis of wave energy devices with air-filled compressible submerged volumes, where variability of volume is achieved by means of a horizontal surface free to move up and down relative to the body. An analysis of bodies without power take-off (PTO) systems is first presented to demonstrate the positive effects a compressible volume could have on the body response. Subsequently, two compressible device variations are analysed. In the first variation, the compressible volume is connected to a fixed volume via an air turbine for PTO. In the second variation, a water column separates the compressible volume from another volume, which is fitted with an air turbine open to the atmosphere. Both floating and bottom-fixed, axisymmetric, configurations are considered, and linear analysis is employed throughout. Advantages and disadvantages of each device are examined in detail. Some configurations with displaced volumes less than 2000 m(3) and with constant turbine coefficients are shown to be capable of achieving 80% of the theoretical maximum absorbed power over a wave period range of about 4 s.

  5. Wave energy devices with compressible volumes

    PubMed Central

    Kurniawan, Adi; Greaves, Deborah; Chaplin, John

    2014-01-01

    We present an analysis of wave energy devices with air-filled compressible submerged volumes, where variability of volume is achieved by means of a horizontal surface free to move up and down relative to the body. An analysis of bodies without power take-off (PTO) systems is first presented to demonstrate the positive effects a compressible volume could have on the body response. Subsequently, two compressible device variations are analysed. In the first variation, the compressible volume is connected to a fixed volume via an air turbine for PTO. In the second variation, a water column separates the compressible volume from another volume, which is fitted with an air turbine open to the atmosphere. Both floating and bottom-fixed, axisymmetric, configurations are considered, and linear analysis is employed throughout. Advantages and disadvantages of each device are examined in detail. Some configurations with displaced volumes less than 2000 m3 and with constant turbine coefficients are shown to be capable of achieving 80% of the theoretical maximum absorbed power over a wave period range of about 4 s. PMID:25484609

  6. Plasma wave signatures of collisionless shocks and the role of plasma wave turbulence in shock formation

    NASA Technical Reports Server (NTRS)

    Mellott, M. M.

    1986-01-01

    Observations of the plasma waves associated with collisionless shocks are reviewed, and the understanding of their generation mechanisms and their importance to shock physics are summarized. The emphasis is on waves generated directly at the shock, especially ion acoustic and lower-hybrid-like modes. The observations are discussed in the context of shock structure, with attention given to the distinctions between waves generated in the shock foot and ramp. The behavior of resistive, dispersive, and supercritical quasi-perpendicular shocks is contrasted. Evidence for the operation of various generation mechanisms, including interactions with cross-field currents, gyrating reflected ions, and field-aligned electron beams, are summarized. The various forms of plasma heating which are actually observed are outlined, and the role of the various wave modes in this heating is discussed. Conclusion, it is argued that, while plasma wave turbulence may play a vital role in plasma heating for some special shocks, it is of second-order importance in most cases.

  7. Generation and propagation of shock waves in the exhaust pipe of a 4 cycle automobile engine

    NASA Astrophysics Data System (ADS)

    Sekine, N.; Matsumura, S.; Aoki, K.; Takayama, K.

    1990-07-01

    An experimental investigation was made of reduction of noise generated in the exhaust pipe of a half liter 4-cycle water-cooled automobile gasoline engine. The pressure measurement along the exhaust pipe showed the nonlinear transition of compression waves discharged from the exhaust port of the engine into shock waves. In order to obtain a direct evidence of shock waves in the exhaust pipe, a flow visualization study was also conducted using a double exposure holographic interferometry. Weak shock waves of Mach number 1.09 exist in the exhaust pipe. For the purpose of collecting the data for designing optimum muffler configurations, additional shock tube experiments were carried out. The results indicates that the study of the non-linear wave interaction and propagation is important for the design of muffler.

  8. Examination of the forces controlling dust dispersion by shock waves

    NASA Astrophysics Data System (ADS)

    Ugarte, O. J.; Houim, R. W.; Oran, E. S.

    2017-07-01

    The interaction between a shock wave and a thin layer of inert dust is studied by solving unsteady, multidimensional Navier-Stokes equations representing the interactions between a compressible gas and incompressible particles. The system studied consists of a layer of densely packed limestone dust containing particles of uniform diameter (40 μ m ) that interact with a shock of strength Ms=1.4 . Particle dispersion is investigated by comparing vertical particle accelerations due to Archimedes, gravitational, intergranular, and aerodynamic drag and lift forces. The simulations show that the shock produces two dust regions: a compacted layer and a dispersed region. The layer compaction, which increases the intergranular particle stress, is produced by drag and Archimedes forces. The dispersed dust is produced by forces that change in time as the shock passes. Initially, the dispersion is caused by intergranular forces. Later it is driven by a tradeoff between lift and drag forces. Eventually, drag forces dominate. Comparisons of the computations to experimental shock-tube data reproduced the observed initial growth of the dispersed dust and later leveled off. Particle agglomeration in the experiments made it difficult to determine a true particle size experimentally, although the computations for 40-μ m particles explain the experimental data.

  9. Shock wave structure in heterogeneous reactive media

    SciTech Connect

    Baer, M.R.

    1997-06-01

    Continuum mixture theory and mesoscale modeling are applied to describe the behavior of shock-loaded heterogeneous media. One-dimensional simulations of gas-gun experiments demonstrate that the wave features are well described by mixture theory, including reflected wave behavior and conditions where significant reaction is initiated. Detailed wave fields are resolved in numerical simulations of impact on a lattice of discrete explosive {open_quotes}crystals{close_quotes}. It is shown that rapid distortion first occurs at material contact points; the nature of the dispersive fields includes large amplitude fluctuations of stress over several particle pathlengths. Localization of energy causes {open_quotes}hot-spots{close_quotes} due to shock focusing and plastic work as material flows into interstitial regions.

  10. Modified shock waves for extracorporeal shock wave lithotripsy: a simulation based on the Gilmore formulation.

    PubMed

    Canseco, Guillermo; de Icaza-Herrera, Miguel; Fernández, Francisco; Loske, Achim M

    2011-10-01

    Extracorporeal shock wave lithotripsy (SWL) is a reliable therapy for the treatment of urolithiasis. Nevertheless, improvements to enhance stone fragmentation and reduce tissue damage are still needed. During SWL, cavitation is one of the most important stone fragmentation mechanisms. Bubbles with a diameter between about 7 and 55μm have been reported to expand and collapse after shock wave passage, forming liquid microjets at velocities of up to 400m/s that contribute to the pulverization of renal calculi. Several authors have reported that the fragmentation efficiency may be improved by using tandem shock waves. Tandem SWL is based on the fact that the collapse of a bubble can be intensified if a second shock wave arrives tenths or even a few hundredths of microseconds before its collapse. The object of this study is to determine if tandem pulses consisting of a conventional shock wave (estimated rise time between 1 and 20ns), followed by a slower second pressure profile (0.8μs rise time), have advantages over conventional tandem SWL. The Gilmore equation was used to simulate the influence of the modified pressure field on the dynamics of a single bubble immersed in water and compare the results with the behavior of the same bubble subjected to tandem shock waves. The influence of the delay between pulses on the dynamics of the collapsing bubble was also studied for both conventional and modified tandem waves. For a bubble of 0.07mm, our results indicate that the modified pressure profile enhances cavitation compared to conventional tandem waves at a wide range of delays (10-280μs). According to this, the proposed pressure profile could be more efficient for SWL than conventional tandem shock waves. Similar results were obtained for a ten times smaller bubble.

  11. Plasmons in strongly coupled shock-compressed matter

    SciTech Connect

    Neumayer, P; Fortmann, C; Doppner, T; Davis, P; Falcone, R W; Kritcher, A L; Landen, O L; Lee, H J; Lee, R W; Niemann, C; Pape, S L; Glenzer, S H

    2010-04-15

    We present the first measurements of the plasmon dispersion and damping in laser shock-compressed solid matter. Petawatt laser produced K-{alpha} radiation scatters on boron targets compressed by a 10 ns-long 400 J laser pulse. In the vicinity of the Fermi momentum, the scattering spectra show dispersionless, collisionally damped plasmons, indicating a strongly coupled electron liquid. These observations agree with x-ray scattering calculations that include both the Born-Mermin approximation to account for electron-ion collisional damping and local field corrections reflecting electron-electron correlations.

  12. Predicting the optical behaviour of shock compressed dielectrics

    NASA Astrophysics Data System (ADS)

    Tear, Gareth R.; Proud, William G.

    2017-01-01

    An anisotropic photoelastic model for predicting the optical properties of shock compressed anisotropic dielectrics has been developed for the purpose of investigating the effect of experimental tilt. This model has been used to predict the expected effect of impact and crystallographic tilt on birefringence measurements for a plate impact experiment. It was found that the expected systematic error to the birefringence measurement caused by experimental tilt was likely to be negligible. Predictions for various common anisotropic minerals compressed along the a-axis are also presented and the model is compared to experimental plate impact data from PMMA and sapphire.

  13. Area change effects on shock wave propagation

    NASA Astrophysics Data System (ADS)

    Dowse, J.; Skews, B.

    2014-07-01

    Experimental testing was conducted for a planar shock wave of incident Mach number propagating through one of three compound parabolic profiles of 130, 195 or 260 mm in length, all of which exhibit an 80 % reduction in area. Both high-resolution single shot and low-resolution video were used in a schlieren arrangement. Results showed three main types of flow scenarios for propagation through a gradual area reduction, and an optimal net increase of 12.7 % in shock Mach number was determined for the longest profile, which is within 5 % of theoretical predictions using Milton's modified Chester-Chisnell-Whitham relation.

  14. Shock wave interactions between slender bodies. Some aspects of three-dimensional shock wave diffraction

    NASA Astrophysics Data System (ADS)

    Hooseria, S. J.; Skews, B. W.

    2017-01-01

    A complex interference flowfield consisting of multiple shocks and expansion waves is produced when high-speed slender bodies are placed in close proximity. The disturbances originating from a generator body impinge onto the adjacent receiver body, modifying the local flow conditions over the receiver. This paper aims to uncover the basic gas dynamics produced by two closely spaced slender bodies in a supersonic freestream. Experiments and numerical simulations were used to interpret the flowfield, where good agreement between the predictions and measurements was observed. The numerical data were then used to characterise the attenuation associated with shock wave diffraction, which was found to be interdependent with the bow shock contact perimeter over the receiver bodies. Shock-induced boundary layer separation was observed over the conical and hemispherical receiver bodies. These strong viscous-shock interactions result in double-reflected, as well as double-diffracted shock wave geometries in the interference region, and the diffracting waves progress over the conical and hemispherical receivers' surfaces in "lambda" type configurations. This gives evidence that viscous effects can have a substantial influence on the local bow shock structure surrounding high-speed slender bodies in close proximity.

  15. Method and apparatus for determining pressure-induced frequency-shifts in shock-compressed materials

    DOEpatents

    Moore, David S.; Schmidt, Stephen C.

    1985-01-01

    A method and an apparatus for conducting coherent anti-Stokes Raman scattering spectroscopy in shock-compressed materials are disclosed. The apparatus includes a sample vessel having an optically transparent wall and an opposing optically reflective wall. Two coherent laser beams, a pump beam and a broadband Stokes beam, are directed through the window and focused on a portion of the sample. In the preferred embodiment, a projectile is fired from a high-pressure gas gun to impact the outside of the reflective wall, generating a planar shock wave which travels through the sample toward the window. The pump and Stokes beams result in the emission from the shock-compressed sample of a coherent anti-Stokes beam, which is emitted toward the approaching reflective wall of the vessel and reflected back through the window. The anti-Stokes beam is folded into a spectrometer for frequency analysis. The results of such analysis are useful for determining chemical and physical phenomena which occur during the shock-compression of the sample.

  16. Development of a broadband reflectivity diagnostic for laser driven shock compression experiments

    SciTech Connect

    Ali, S. J.; Bolme, C. A.; Collins, G. W.; Jeanloz, R.

    2015-04-01

    A normal - incidence visible and near - infrared Shock Wave Optical Reflectivity Diagnostic (SWORD) was constructed to investigate changes in the optical properties of materials under dynamic laser compression . Documenting wavelength - and time - dependent changes in the optical properties of laser - shock compressed samples has been difficult, primarily due to the small sample sizes and short time scales involved , but we succeeded in doing so by broadening a series of time delayed 800 - nm pulses from an ultra fast Ti: sapphire laser to generate high - intensity broadband light at nanosecond time scales . This diagnostic was demonstrated over the wavelength range 450 to 1150 nm with up to 16 time displaced spectra during a single shock experiment. Simultaneous off - normal incidence velocity interferometry (VISAR) characterize d the sample under laser - compression , and also provide d a n independent reflectivity measurement at 532 nm wavelength . Lastly, the shock - driven semiconductor - to - metallic transition in germanium was documented by way of reflectivity measurements with 0.5 ns time resolution and a wavelength resolution of 10 nm .

  17. Method and apparatus for determining pressure-induced frequency-shifts in shock-compressed materials

    DOEpatents

    Moore, D.S.; Schmidt, S.C.

    1983-12-16

    A method and an apparatus for conducting coherent anti-Stokes Raman scattering spectroscopy in shock-compressed materials are disclosed. The apparatus includes a sample vessel having an optically transparent wall and an opposing optically reflective wall. Two coherent laser beams, a pump beam and a broadband Stokes beam, are directed through the window and focused on a portion of the sample. In the preferred embodiment, a projectile is fired from a high-pressure gas gun to impact the outside of the reflective wall, generating a planar shock wave which travels through the sample toward the window. The pump and Stokes beams result in the emission from the shock-compressed sample of a coherent anti-Stokes beam, which is emitted toward the approaching reflective wall of the vessel and reflected back through the window. The anti-Stokes beam is folded into a spectrometer for frequency analysis. The results of such analysis are useful for determining chemical and physical phenomena which occur during the shock-compression of the sample.

  18. A new apparatus to induce lysis of planktonic microbial cells by shock compression, cavitation and spray

    PubMed Central

    Schiffer, A.; Gardner, M. N.; Lynn, R. H.

    2017-01-01

    Experiments were conducted on an aqueous growth medium containing cultures of Escherichia coli (E. coli) XL1-Blue, to investigate, in a single experiment, the effect of two types of dynamic mechanical loading on cellular integrity. A bespoke shock tube was used to subject separate portions of a planktonic bacterial culture to two different loading sequences: (i) shock compression followed by cavitation, and (ii) shock compression followed by spray. The apparatus allows the generation of an adjustable loading shock wave of magnitude up to 300 MPa in a sterile laboratory environment. Cultures of E. coli were tested with this apparatus and the spread-plate technique was used to measure the survivability after mechanical loading. The loading sequence (ii) gave higher mortality than (i), suggesting that the bacteria are more vulnerable to shear deformation and cavitation than to hydrostatic compression. We present the results of preliminary experiments and suggestions for further experimental work; we discuss the potential applications of this technique to sterilize large volumes of fluid samples. PMID:28405383

  19. A new apparatus to induce lysis of planktonic microbial cells by shock compression, cavitation and spray

    NASA Astrophysics Data System (ADS)

    Schiffer, A.; Gardner, M. N.; Lynn, R. H.; Tagarielli, V. L.

    2017-03-01

    Experiments were conducted on an aqueous growth medium containing cultures of Escherichia coli (E. coli) XL1-Blue, to investigate, in a single experiment, the effect of two types of dynamic mechanical loading on cellular integrity. A bespoke shock tube was used to subject separate portions of a planktonic bacterial culture to two different loading sequences: (i) shock compression followed by cavitation, and (ii) shock compression followed by spray. The apparatus allows the generation of an adjustable loading shock wave of magnitude up to 300 MPa in a sterile laboratory environment. Cultures of E. coli were tested with this apparatus and the spread-plate technique was used to measure the survivability after mechanical loading. The loading sequence (ii) gave higher mortality than (i), suggesting that the bacteria are more vulnerable to shear deformation and cavitation than to hydrostatic compression. We present the results of preliminary experiments and suggestions for further experimental work; we discuss the potential applications of this technique to sterilize large volumes of fluid samples.

  20. Colloidal solitary waves with temperature dependent compressibility

    NASA Astrophysics Data System (ADS)

    Azmi, A.; Marchant, T. R.

    2014-05-01

    Spatial solitary waves which form in colloidal suspensions of dielectric nanoparticles are considered. The interactions, or compressibility, of the colloidal particles, is modelled using a series in the particle density, or packing fraction, where the virial, or series, coefficients depend on the type of particle interaction model. Both the theoretical hard disk and sphere repulsive models, and a model with temperature dependent compressibility, are considered. Experimental results show that particle interactions can be temperature dependent and either repulsive or attractive in nature, so we model the second virial coefficient using a physically realistic temperature power law. One- and two-dimensional semi-analytical colloidal solitary wave solutions are found. Trial functions, based on the form of the nonlinear Schrödinger equation soliton, are used, together with averaging, to develop the semi-analytical solutions. When the background packing fraction is low, the one-dimensional solitary waves have three solutions branches (with a bistable regime) while the two-dimensional solitary waves have two solution branches, with a single stable branch. The temperature dependent second virial coefficient results in changes to the solitary wave properties and the parameter space, in which multiple solutions branches occur. An excellent comparison is found between the semi-analytical and numerical solutions.

  1. A multi-scale approach to molecular dynamics simulations of shock waves

    SciTech Connect

    Reed, E J; Fried, L E; Manaa, M R; Joannopoulos, J D

    2004-09-03

    Study of the propagation of shock waves in condensed matter has led to new discoveries ranging from new metastable states of carbon [1] to the metallic conductivity of hydrogen in Jupiter, [2] but progress in understanding the microscopic details of shocked materials has been extremely difficult. Complications can include the unexpected formation of metastable states of matter that determine the structure, instabilities, and time-evolution of the shock wave. [1,3] The formation of these metastable states can depend on the time-dependent thermodynamic pathway that the material follows behind the shock front. Furthermore, the states of matter observed in the shock wave can depend on the timescale on which observation is made. [4,1] Significant progress in understanding these microscopic details has been made through molecular dynamics simulations using the popular non-equilibrium molecular dynamics (NEMD) approach to atomistic simulation of shock compression. [5] The NEMD method involves creating a shock at one edge of a large system by assigning some atoms at the edge a fixed velocity. The shock propagates across the computational cell to the opposite side. The computational work required by NEMD scales at least quadratically in the evolution time because larger systems are needed for longer simulations to prevent the shock wave from reflecting from the edge of the computational cell and propagating back into the cell. When quantum mechanical methods with poor scaling of computational effort with system size are employed, this approach to shock simulations rapidly becomes impossible.

  2. Numerical simulation of shock wave generation and focusing in shock wave lithotripsy

    NASA Astrophysics Data System (ADS)

    Krimmel, Jeff; Colonius, Tim

    2007-11-01

    Shock wave lithotripsy is a procedure where focused shock waves are fired at kidney stones in order to pulverize them. Many lithotripters with different source mechanisms and reflector shapes (or lenses) are in clinical use, but accurate prediction of focal region pressure is made difficult by nonlinearity and cavitation. We report on development of a numerical simulation framework aimed at accurate prediction of focal region flow physics. Shock wave generation and beam focusing are simulated via the Euler equations with MUSCL-type shock capturing scheme and adaptive mesh-refinement (Berger and Oliger, 1984). In future work, a bubbly cavitating flow model will be added. Electrohydraulic, electromagnetic, and piezoelectric lithotripters are modeled with axisymmetric and three-dimensional geometries. In the electrohydraulic case, a simple expanding bubble model simulates spark firing. In the piezoelectric case, a boundary condition prescribing the motion of individual elements is used. Amplitudes and durations of calculated focal region waveforms are in reasonable agreement with experimental data.

  3. Frequency shift measurement in shock-compressed materials

    DOEpatents

    Moore, D.S.; Schmidt, S.C.

    1984-02-21

    A method is disclosed for determining molecular vibrational frequencies in shock-compressed transparent materials. A single laser beam pulse is directed into a sample material while the material is shock-compressed from a direction opposite that of the incident laser beam. A Stokes beam produced by stimulated Raman scattering is emitted back along the path of the incident laser beam, that is, in the opposite direction to that of the incident laser beam. The Stokes beam is separated from the incident beam and its frequency measured. The difference in frequency between the Stokes beam and the incident beam is representative of the characteristic frequency of the Raman active mode of the sample. Both the incident beam and the Stokes beam pass perpendicularly through the stock front advancing through the sample, thereby minimizing adverse effects of refraction.

  4. Shock Experiments on Pre-Compressed Fluid Helium

    SciTech Connect

    Eggert, J. H.; Celliers, P. M.; Hicks, D. G.; Rygg, J. R.; Collins, G. W.; Brygoo, S.; Loubeyre, P.; McWilliams, R. S.; Spaulding, D.; Jeanloz, R.; Boehly, T. R.

    2009-09-10

    We summarize current methods and results for coupling laser-induced shocks into pre-compressed Helium contained in a diamond anvil cell (DAC). We are able to load helium, hydrogen, deuterium, and helium-hydrogen mixtures into a DAC and propagate a laser-generated shock into the pre-compressed sample. This technique has allowed us to measure the Hugoniot for helium at initial densities ranging from 1 to 3.5 times liquid density. We have developed and used a methodology whereby all of our measurements are referenced to crystalline quartz, which allows us to update our results as the properties of quartz are refined in the future. We also report the identification and elimination of severe electro-magnetic pulses (EMP) associated with plasma stagnation associated with ablation in a DAC.

  5. Enhanced densification under shock compression in porous silicon

    DOE PAGES

    Lane, J. Matthew; Thompson, Aidan Patrick; Vogler, Tracy

    2014-10-27

    Under shock compression, most porous materials exhibit lower densities for a given pressure than that of a full-dense sample of the same material. However, some porous materials exhibit an anomalous, or enhanced, densification under shock compression. The mechanism driving this behavior was not completely determined. We present evidence from atomistic simulation that pure silicon belongs to this anomalous class of materials and demonstrate the associated mechanisms responsible for the effect in porous silicon. Atomistic response indicates that local shear strain in the neighborhood of collapsing pores catalyzes a local solid-solid phase transformation even when bulk pressures are below the thermodynamicmore » phase transformation pressure. This metastable, local, and partial, solid-solid phase transformation, which accounts for the enhanced densification in silicon, is driven by the local stress state near the void, not equilibrium thermodynamics. This mechanism may also explain the phenomenon in other covalently bonded materials.« less

  6. Enhanced densification under shock compression in porous silicon

    SciTech Connect

    Lane, J. Matthew; Thompson, Aidan Patrick; Vogler, Tracy

    2014-10-27

    Under shock compression, most porous materials exhibit lower densities for a given pressure than that of a full-dense sample of the same material. However, some porous materials exhibit an anomalous, or enhanced, densification under shock compression. The mechanism driving this behavior was not completely determined. We present evidence from atomistic simulation that pure silicon belongs to this anomalous class of materials and demonstrate the associated mechanisms responsible for the effect in porous silicon. Atomistic response indicates that local shear strain in the neighborhood of collapsing pores catalyzes a local solid-solid phase transformation even when bulk pressures are below the thermodynamic phase transformation pressure. This metastable, local, and partial, solid-solid phase transformation, which accounts for the enhanced densification in silicon, is driven by the local stress state near the void, not equilibrium thermodynamics. This mechanism may also explain the phenomenon in other covalently bonded materials.

  7. Experimental Investigation of Passive Shock Wave Mitigation using Obstacle Arrangements

    NASA Astrophysics Data System (ADS)

    Nguyen, Monica; Wan, Qian; Eliasson, Veronica

    2014-11-01

    With its vast range in applications, especially in the defense industry, shock wave mitigation is an ongoing research area of interest to the shock dynamics community. Passive shock wave mitigation methods range from forcing the shock wave to abruptly change its direction to introducing barriers or obstacles of various shapes and materials in the path of the shock wave. Obstacles provide attenuation through complicated shock wave interactions and reflections. In this work, we have performed shock tube experiments to investigate shock wave mitigation due to solid obstacles placed along the curve of a logarithmic spiral. Different shapes (cylindrical and square) of obstacles with different materials (solid and foam) have been used. High-speed schlieren optics and background-oriented schlieren techniques have been used together with pressure measurements to quantify the effects of mitigation. Results have also been compared to numerical simulations and show good agreement.

  8. Characterization of mechanical shock waves in aluminum 6061-T6 using a high power laser pulse

    NASA Astrophysics Data System (ADS)

    Gonzalez Romero, J. R.; García-Torales, G.; Gómez Rosas, G.; Ocaña, J. L.; Flores, Jorge L.

    2016-09-01

    Strengthening techniques allows enhance metal physical properties. Laser shock peening (LSP) technique consist in a surface treatment which a high power laser pulse induces a compressive residual stress field through mechanical shock waves, increasing hardness, corrosion resistance, fatigue resistance. In comparison with the shot peening technique, LSP is a method that allows precision controlling the laser incidence on the surface under treatment increasing the surface quality in the surface under treatment. In this work, mechanical shock waves are induced in aluminum and measure using two different experimental approaches. First, using a PVDZ sensors and secondly, strain gauges are used. Experimental results are presented.

  9. Pseudo-shock waves and their interactions in high-speed intakes

    NASA Astrophysics Data System (ADS)

    Gnani, F.; Zare-Behtash, H.; Kontis, K.

    2016-04-01

    In an air-breathing engine the flow deceleration from supersonic to subsonic conditions takes places inside the isolator through a gradual compression consisting of a series of shock waves. The wave system, referred to as a pseudo-shock wave or shock train, establishes the combustion chamber entrance conditions, and therefore influences the performance of the entire propulsion system. The characteristics of the pseudo-shock depend on a number of variables which make this flow phenomenon particularly challenging to be analysed. Difficulties in experimentally obtaining accurate flow quantities at high speeds and discrepancies of numerical approaches with measured data have been readily reported. Understanding the flow physics in the presence of the interaction of numerous shock waves with the boundary layer in internal flows is essential to developing methods and control strategies. To counteract the negative effects of shock wave/boundary layer interactions, which are responsible for the engine unstart process, multiple flow control methodologies have been proposed. Improved analytical models, advanced experimental methodologies and numerical simulations have allowed a more in-depth analysis of the flow physics. The present paper aims to bring together the main results, on the shock train structure and its associated phenomena inside isolators, studied using the aforementioned tools. Several promising flow control techniques that have more recently been applied to manipulate the shock wave/boundary layer interaction are also examined in this review.

  10. In vitro study of the mechanical effects of shock-wave lithotripsy.

    PubMed

    Howard, D; Sturtevant, B

    1997-01-01

    Impulsive stress in repeated shock waves administered during extracorporeal shock-wave lithotripsy (ESWL) causes injury to kidney tissue. In a study of the mechanical input of ESWL, the effects of focused shock waves on thin planar polymeric membranes immersed in a variety of tissue-mimicking fluids have been examined. A direct mechanism of failure by shock compression and an indirect mechanism by bubble collapse have been observed. Thin membranes are easily damaged by bubble collapse. After propagating through cavitation-free acoustically heterogeneous media (liquids mixed with hollow glass spheres, and tissue) shock waves cause membranes to fail in fatigue by a shearing mechanism. As is characteristic of dynamic fatigue, the failure stress increases with strain rate, determined by the amplitude and rise time of the attenuated shock wave. Shocks with large amplitude and short rise time (i.e., in uniform media) cause no damage. Thus the inhomogeneity of tissue is likely to contribute to injury in ESWL. A definition of dose is proposed which yields a criterion for damage based on measurable shock wave properties.

  11. Burnett-Cattaneo Continuum Theory for Shock Waves

    NASA Astrophysics Data System (ADS)

    Holian, B. L.; Mareschal, M.; Ravelo, R.

    2011-03-01

    We model strong shockwave propagation, both in the ideal gas and in the dense Lennard-Jones fluid, using a refinement of earlier work, which accounts for the cold compression by a nonlinear, Burnett-like, strain-rate dependence of the thermal conductivity, and relaxation of temperature components on the hot, compressed side of the shock front. The relaxation of the disequilibrium among the three components of the kinetic temperature, namely, the difference between the temperature in the direction of a planar shock wave and those in the transverse directions, particularly in the region near the shock front, is accomplished by a rigorous application of the Cattaneo-Maxwell relaxation equation to a reference state, namely, the steady shockwave solution of linear Navier-Stokes-Fourier theory, along with the nonlinear Burnett heat-flux term. Our new continuum theory is in nearly quantitative agreement with non-equilibrium molecular-dynamics simulations under strong shockwave conditions. Part of this work supported by the U.S. Department of Energy under contract DE-AC5206NA25396.

  12. Shock compression behavior of a S2-glass fiber reinforced polymer composite

    NASA Astrophysics Data System (ADS)

    Tsai, Liren; Yuan, Fuping; Prakash, Vikas; Dandekar, Dattatraya P.

    2009-05-01

    Synthetic heterogeneous material systems, e.g., layered composite materials with organic matrices reinforced by glass fibers (GRP), are attractive materials for a variety of lightweight armor applications. However, while the dynamic response of homogeneous materials, such as, metals and ceramics, has been well documented, the ballistic response of heterogeneous material systems is poorly understood. In the present study, in an attempt to better understand the shock-induced compression response of GRPs, a series of plate impact experiments were conducted on a S2-glas fiber reinforced polymer composite comprising S2-glass woven roving in a Cycom 4102 polyester resin matrix. The plate-impact experiments were conducted using an 82.5 mm bore single-stage gas-gun at the Case Western Reserve University. The history of the shock-induced free-surface particle velocity at the rear surface of the target plate was monitored using the multibeam VALYN™ VISAR system. The results of the experiments indicate the absence of an elastic front in the shock-induced free-surface particle velocity profile in the GRP. Moreover, in the low impact velocity range, relatively weak late-time oscillations are observed in the particle velocity profiles. Increasing the amplitude of the shock-induced compression resulted in a decrease in the rise-time of the shock wave front. The critical shock stress amplitude at which a clear shock-front is seen to develop during the shock loading was determined to be between 1.5 and 2.0 GPa. The results of the experiments are used to obtain the equation of state of the GRP in the stress range 0.04-20 GPa. Moreover, the Hugoniot curve (Hugoniot stress versus Hugoniot strain) was calculated using the Rankine-Hugoniot relationships; the departure of the Hugoniot stress versus the particle velocity curve from linearity allowed the estimation of the Hugoniot elastic limit of the GRP to be about 1.6 GPa.

  13. Fluid dynamics of the shock wave reactor

    NASA Astrophysics Data System (ADS)

    Masse, Robert Kenneth

    2000-10-01

    High commercial incentives have driven conventional olefin production technologies to near their material limits, leaving the possibility of further efficiency improvements only in the development of entirely new techniques. One strategy known as the Shock Wave Reactor, which employs gas dynamic processes to circumvent limitations of conventional reactors, has been demonstrated effective at the University of Washington. Preheated hydrocarbon feedstock and a high enthalpy carrier gas (steam) are supersonically mixed at a temperature below that required for thermal cracking. Temperature recovery is then effected via shock recompression to initiate pyrolysis. The evolution to proof-of-concept and analysis of experiments employing ethane and propane feedstocks are presented. The Shock Wave Reactor's high enthalpy steam and ethane flows severely limit diagnostic capability in the proof-of-concept experiment. Thus, a preliminary blow down supersonic air tunnel of similar geometry has been constructed to investigate recompression stability and (especially) rapid supersonic mixing necessary for successful operation of the Shock Wave Reactor. The mixing capabilities of blade nozzle arrays are therefore studied in the air experiment and compared with analytical models. Mixing is visualized through Schlieren imaging and direct photography of condensation in carbon dioxide injection, and interpretation of visual data is supported by pressure measurement and flow sampling. The influence of convective Mach number is addressed. Additionally, thermal behavior of a blade nozzle array is analyzed for comparison to data obtained in the course of succeeding proof-of-concept experiments. Proof-of-concept is naturally succeeded by interest in industrial adaptation of the Shock Wave Reactor, particularly with regard to issues involving the scaling and refinement of the shock recompression. Hence, an additional, variable geometry air tunnel has been constructed to study the parameter

  14. Stability of spherical converging shock wave

    SciTech Connect

    Murakami, M.; Sanz, J.; Iwamoto, Y.

    2015-07-15

    Based on Guderley's self-similar solution, stability of spherical converging shock wave is studied. A rigorous linear perturbation theory is developed, in which the growth rate of perturbation is given as a function of the spherical harmonic number ℓ and the specific heats ratio γ. Numerical calculation reveals the existence of a γ-dependent cut-off mode number ℓ{sub c}, such that all the eigenmode perturbations for ℓ > ℓ{sub c} are smeared out as the shock wave converges at the center. The analysis is applied to partially spherical geometries to give significant implication for different ignition schemes of inertial confinement fusion. Two-dimensional hydrodynamic simulations are performed to verify the theory.

  15. Material Point Methods for Shock Waves

    NASA Astrophysics Data System (ADS)

    Zhang, Duan; Dhakal, Tilak

    2016-11-01

    Particle methods are often the choice for problems involving large material deformation with history dependent material models. Often large deformation of a material is caused by shock loading, therefore accurate calculation of shock waves is important for particle methods. In this work, we study four major versions (original MPM, GIMP, CPDI, and DDMP) of material point methods, using a weak one-dimensional isothermal shock of ideal gas as an example. The original MPM fails. With a small number of particles, the GIMP and the CPDI methods produce reasonable results. However, as the number of particles increases these methods do not converge and produce pressure spikes. With sparse particles, DDMP results are unsatisfactory. As the number of particles increases, DDMP results converge to correct solutions, but the large number of particles needed for an accurate result makes the method very expensive to use in shock wave problems. To improve the numerical accuracy while preserving the convergence, conservation, and smoothness of the DDMP method, a new numerical integration scheme is introduced. The improved DDMP method is only slightly more expensive than the original DDMP method, but accuracy improvements are significant as shown by numerical examples. This work was performed under the auspices of the United States Department of Energy.

  16. Compressible turbulence and shock-capturing using a variational multiscale method

    NASA Astrophysics Data System (ADS)

    Garai, Anirban; Burgess, Nicholas; Murman, Scott; Diosady, Laslo

    2016-11-01

    We have previously developed a dynamic extension of Hughes' variational multiscale method which is implemented in an entropy-stable Discontinuous-Galerkin spectral-element solver. This solver and sub-grid model have been examined on standard low-speed benchmark flows, e.g. homogeneous turbulence, channel flow, etc. Here we extend the approach to higher speeds where compressibility effects are no longer insignificant, and the flowfields develop unsteady shocklets and shock waves. Homogeneous isotropic turbulence at high turbulent Mach number is tested for two cases - decaying and passing through a normal shock. Numerical simulations using the multiscale sub-grid model, no sub-grid model, and a variation of Barter and Darmofal's shock-capturing scheme are examined in isolation and combination. The computed results are compared against theoretical observations and previous computational results.

  17. Symmetry of spherically converging shock waves through reflection, relating to the shock ignition fusion energy scheme.

    PubMed

    Davie, C J; Evans, R G

    2013-05-03

    We examine the properties of perturbed spherically imploding shock waves in an ideal fluid through the collapse, bounce, and development into an outgoing shock wave. We find broad conservation of the size and shape of ingoing and outgoing perturbations when viewed at the same radius. The outgoing shock recovers the velocity of the unperturbed shock outside the strongly distorted core. The results are presented in the context of the robustness of the shock ignition approach to inertial fusion energy.

  18. Three-dimensional shock-wave/boundary-layer interactions with bleed through a circular hole

    NASA Technical Reports Server (NTRS)

    Rimlinger, M. J.; Shih, T. I.-P.; Chyu, W. J.

    1992-01-01

    Computations were performed to study three-dimensional (3-D), shock-wave/boundary-layer interactions on a flat plate in which fluid in the boundary layer was bled through a circular hole into a plenum to control shock-wave induced separation. Results are presented which show the details of the 3-D flowfield about the bleed hole and how bleed-hole placement relative to shock-wave impingement affect upstream, spanwise, and downstream influence lengths. This study revealed an underlying mechanisms by which bleed holes can affect shock-wave/boundary-layer interactions. This investigation is based on the ensemble-averaged, "full-compressible" Navier-Stokes equations closed by the Baldwin-Lomax turbulence model. Solutions to these equations were obtained by an implicit finite-volume method based on the partially-split, two-factored algorithm of Steger.

  19. Three-dimensional shock-wave/boundary-layer interactions with bleed through a circular hole

    NASA Technical Reports Server (NTRS)

    Rimlinger, M. J.; Shih, T. I.-P.; Chyu, W. J.

    1992-01-01

    Computations were performed to study three-dimensional (3-D), shock-wave/boundary-layer interactions on a flat plate in which fluid in the boundary layer was bled through a circular hole into a plenum to control shock-wave induced separation. Results are presented which show the details of the 3-D flowfield about the bleed hole and how bleed-hole placement relative to shock-wave impingement affect upstream, spanwise, and downstream influence lengths. This study revealed an underlying mechanisms by which bleed holes can affect shock-wave/boundary-layer interactions. This investigation is based on the ensemble-averaged, "full-compressible" Navier-Stokes equations closed by the Baldwin-Lomax turbulence model. Solutions to these equations were obtained by an implicit finite-volume method based on the partially-split, two-factored algorithm of Steger.

  20. Three-dimensional characteristics of solar coronal shocks determined from observations; Geometry, Kinematics, and Compression ratio

    NASA Astrophysics Data System (ADS)

    Kwon, Ryun Young; Vourlidas, Angelos

    2017-08-01

    We investigate the three-dimensional (3D) characteristics of coronal shocks associated with Coronal Mass Ejections (CMEs), in terms of geometry, kinematics, and density compression ratio, employing a new method we have developed. The method uses multi-viewpoint observations from the STEREO-A, -B and SOHO coronagraphs. The 3D structure and kinematics of coronal shock waves and the driving CMEs are derived separately using a forward modeling method. We analyze two CMEs that are observed as halos by the three spacecraft, and the peak speeds are over 2000 km s-1. From the 3D modeling, we find (1) the coronal shock waves are spherical apparently enclosing the Sun, in which the angular widths are much wider than those of CMEs (92° and 252° versus 58° and 91°), indicating shock waves are propagating away from the CMEs in the azimuthal directions, and (2) the speeds of the shock waves around the CME noses are comparable to those of the CME noses, but the speeds at the lateral flanks seem to be limited to the local fast magnetosonic speed. Applying our new method, we determine electron densities in the shock sheaths, the downstream-upstream density ratios, and the Mach numbers. We find (1) the sheath electron densities decrease with height in general but have the maximum near the CME noses, (2) the density ratios and Mach numbers also seem to depend on the position angle from the CME nose to the far-flank but are more or less constant in time, while the sheath electron densities and speeds decrease with time, because of the reduced local Alfven speed with height, and (3) the shocks could be supercritical in a wider spatial range, and it lasts longer, than those of what have been reported in the past. We conclude that the shock wave associated with an energetic CME is a phenomenon that is becoming a non-driven (blast-type), nearly freely propagating wave at the flank from a driven (bow- and/or piston-type) wave near the CME nose.

  1. Optimizing Shock Wave Lithotripsy: A Comprehensive Review

    PubMed Central

    McClain, Paul D; Lange, Jessica N; Assimos, Dean G

    2013-01-01

    Shock wave lithotripsy is a commonly used procedure for eradicating upper urinary tract stones in patients who require treatment. A number of methods have been proposed to improve the results of this procedure, including proper patient selection, modifications in technique, adjunctive therapy to facilitate elimination of fragments, and changes in lithotripter design. This article assesses the utility of these measures through an analysis of contemporary literature. PMID:24082843

  2. Gas turbine power plant with supersonic shock compression ramps

    DOEpatents

    Lawlor, Shawn P.; Novaresi, Mark A.; Cornelius, Charles C.

    2008-10-14

    A gas turbine engine. The engine is based on the use of a gas turbine driven rotor having a compression ramp traveling at a local supersonic inlet velocity (based on the combination of inlet gas velocity and tangential speed of the ramp) which compresses inlet gas against a stationary sidewall. The supersonic compressor efficiently achieves high compression ratios while utilizing a compact, stabilized gasdynamic flow path. Operated at supersonic speeds, the inlet stabilizes an oblique/normal shock system in the gasdynamic flow path formed between the rim of the rotor, the strakes, and a stationary external housing. Part load efficiency is enhanced by use of a lean pre-mix system, a pre-swirl compressor, and a bypass stream to bleed a portion of the gas after passing through the pre-swirl compressor to the combustion gas outlet. Use of a stationary low NOx combustor provides excellent emissions results.

  3. Ionospheric shock waves triggered by rockets

    NASA Astrophysics Data System (ADS)

    Lin, C. H.; Lin, J. T.; Chen, C. H.; Liu, J. Y.; Sun, Y. Y.; Kakinami, Y.; Matsumura, M.; Chen, W. H.; Liu, H.; Rau, R. J.

    2014-09-01

    This paper presents a two-dimensional structure of the shock wave signatures in ionospheric electron density resulting from a rocket transit using the rate of change of the total electron content (TEC) derived from ground-based GPS receivers around Japan and Taiwan for the first time. From the TEC maps constructed for the 2009 North Korea (NK) Taepodong-2 and 2013 South Korea (SK) Korea Space Launch Vehicle-II (KSLV-II) rocket launches, features of the V-shaped shock wave fronts in TEC perturbations are prominently seen. These fronts, with periods of 100-600 s, produced by the propulsive blasts of the rockets appear immediately and then propagate perpendicularly outward from the rocket trajectory with supersonic velocities between 800-1200 m s-1 for both events. Additionally, clear rocket exhaust depletions of TECs are seen along the trajectory and are deflected by the background thermospheric neutral wind. Twenty minutes after the rocket transits, delayed electron density perturbation waves propagating along the bow wave direction appear with phase velocities of 800-1200 m s-1. According to their propagation character, these delayed waves may be generated by rocket exhaust plumes at earlier rocket locations at lower altitudes.

  4. Shock Waves in Hall-MHD

    NASA Astrophysics Data System (ADS)

    Hagstrom, George; Hameiri, Eliezer

    2012-03-01

    Hall-MHD is a partial differential equation of degenerate parabolic type that describes the dynamics of an ideal two fluid plasma with massless electrons. We study shock waves and discontinuities in this system. We characterize planar travelling wave solutions and find solutions with discontinuities in the hydrodynamic variables. These solutions, which correspond to the ion-acoustic wave, arise due to the presence of hydrodynamic real characteristics in Hall-MHD. We demonstrate finite-time discontinuity formation for certain types of initial data with discontinuous derivatives and study the shock structure under different regularizations. We also explore the possible existence of solutions with discontinuous magnetic field. A non-algebraic, non-local set of jump conditions is derived under the assumption of [B]!=0. These conditions are used to study the contact discontinuity and it is shown that massless electrons crossing the surface of discontinuity may enter and leave at different locations. These conditions suggest the possible existence of mathematically novel shocks in Hall-MHD.

  5. Shock Waves and Commutation Speed of Memristors

    NASA Astrophysics Data System (ADS)

    Tang, Shao; Tesler, Federico; Marlasca, Fernando Gomez; Levy, Pablo; Dobrosavljević, V.; Rozenberg, Marcelo

    2016-01-01

    Progress of silicon-based technology is nearing its physical limit, as the minimum feature size of components is reaching a mere 10 nm. The resistive switching behavior of transition metal oxides and the associated memristor device is emerging as a competitive technology for next-generation electronics. Significant progress has already been made in the past decade, and devices are beginning to hit the market; however, this progress has mainly been the result of empirical trial and error. Hence, gaining theoretical insight is of the essence. In the present work, we report the striking result of a connection between the resistive switching and shock-wave formation, a classic topic of nonlinear dynamics. We argue that the profile of oxygen vacancies that migrate during the commutation forms a shock wave that propagates through a highly resistive region of the device. We validate the scenario by means of model simulations and experiments in a manganese-oxide-based memristor device, and we extend our theory to the case of binary oxides. The shock-wave scenario brings unprecedented physical insight and enables us to rationalize the process of oxygen-vacancy-driven resistive change with direct implications for a key technological aspect—the commutation speed.

  6. Innovations in shock wave lithotripsy technology

    NASA Astrophysics Data System (ADS)

    Zhong, Pei; Zhou, Yufeng; Zhu, Songlin; Cocks, Franklin; Preminger, Glenn

    2003-10-01

    Since its introduction in early 1980s, shock wave lithotripsy (SWL) has been used widely in clinic for the treatment of kidney and upper urinary stones. Although a variety of methods have been developed for shock wave generation, coupling, and focusing, the core of SWL technology has not changed significantly. In this talk, we will present a summary of our research efforts, aiming to provide innovations in SWL technology. Our strategy is to first better understand the mechanisms by which stone comminution and tissue injury are produced in SWL using various experimental and theoretical techniques. Based on this knowledge, we then developed novel techniques that can optimize the effect of cavitation in SWL via modification of the waveform profile, pressure distribution, and pulse sequence of lithotripter-generated shock waves. These new techniques were upgraded on a Dornier HM-3 lithotripter, the gold standard in SWL. Both in vitro phantom and in vivo animal experiments were carried out which demonstrated that the performance and safety of the upgraded HM-3 lithotripter is superior to the original HM-3 lithotripter. Finally, strategies to improve stone comminution efficiency while reducing tissue injury in SWL will be presented. [Work supported by NIH DK52985 and DK58266.

  7. Shock waves in a Z-pinch and the formation of high energy density plasma

    SciTech Connect

    Rahman, H. U.; Wessel, F. J.; Ney, P.; Presura, R.; Ellahi, Rahmat; Shukla, P. K.

    2012-12-15

    A Z-pinch liner, imploding onto a target plasma, evolves in a step-wise manner, producing a stable, magneto-inertial, high-energy-density plasma compression. The typical configuration is a cylindrical, high-atomic-number liner imploding onto a low-atomic-number target. The parameters for a terawatt-class machine (e.g., Zebra at the University of Nevada, Reno, Nevada Terawatt Facility) have been simulated. The 2-1/2 D MHD code, MACH2, was used to study this configuration. The requirements are for an initial radius of a few mm for stable implosion; the material densities properly distributed, so that the target is effectively heated initially by shock heating and finally by adiabatic compression; and the liner's thickness adjusted to promote radial current transport and subsequent current amplification in the target. Since the shock velocity is smaller in the liner, than in the target, a stable-shock forms at the interface, allowing the central load to accelerate magnetically and inertially, producing a magneto-inertial implosion and high-energy density plasma. Comparing the implosion dynamics of a low-Z target with those of a high-Z target demonstrates the role of shock waves in terms of compression and heating. In the case of a high-Z target, the shock wave does not play a significant heating role. The shock waves carry current and transport the magnetic field, producing a high density on-axis, at relatively low temperature. Whereas, in the case of a low-Z target, the fast moving shock wave preheats the target during the initial implosion phase, and the later adiabatic compression further heats the target to very high energy density. As a result, the compression ratio required for heating the low-Z plasma to very high energy densities is greatly reduced.

  8. Measurements of the equations of state and spectrum of nonideal xenon plasma under shock compression.

    PubMed

    Zheng, J; Gu, Y J; Chen, Z Y; Chen, Q F

    2010-08-01

    Experimental equations of state on generation of nonideal xenon plasma by intense shock wave compression was presented in the ranges of pressure of 2-16 GPa and temperature of 31-50 kK, and the xenon plasma with the nonideal coupling parameter Γ range from 0.6-2.1 was generated. The shock wave was produced using the flyer plate impact and accelerated up to ∼6 km/s with a two-stage light gas gun. Gaseous specimens were shocked from two initial pressures of 0.80 and 4.72 MPa at room temperature. Time-resolved spectral radiation histories were recorded by using a multiwavelength channel pyrometer. The transient spectra with the wavelength range of 460-700 nm were recorded by using a spectrometer to evaluate the shock temperature. Shock velocity was measured and particle velocity was determined by the impedance matching methods. The equations of state of xenon plasma and ionization degree have been discussed in terms of the self-consistent fluid variational theory.

  9. Oxy-acetylene driven laboratory scale shock tubes for studying blast wave effects.

    PubMed

    Courtney, Amy C; Andrusiv, Lubov P; Courtney, Michael W

    2012-04-01

    This paper describes the development and characterization of modular, oxy-acetylene driven laboratory scale shock tubes. Such tools are needed to produce realistic blast waves in a laboratory setting. The pressure-time profiles measured at 1 MHz using high-speed piezoelectric pressure sensors have relevant durations and show a true shock front and exponential decay characteristic of free-field blast waves. Descriptions are included for shock tube diameters of 27-79 mm. A range of peak pressures from 204 kPa to 1187 kPa (with 0.5-5.6% standard error of the mean) were produced by selection of the driver section diameter and distance from the shock tube opening. The peak pressures varied predictably with distance from the shock tube opening while maintaining both a true blast wave profile and relevant pulse duration for distances up to about one diameter from the shock tube opening. This shock tube design provides a more realistic blast profile than current compression-driven shock tubes, and it does not have a large jet effect. In addition, operation does not require specialized personnel or facilities like most blast-driven shock tubes, which reduces operating costs and effort and permits greater throughput and accessibility. It is expected to be useful in assessing the response of various sensors to shock wave loading; assessing the reflection, transmission, and absorption properties of candidate armor materials; assessing material properties at high rates of loading; assessing the response of biological materials to shock wave exposure; and providing a means to validate numerical models of the interaction of shock waves with structures. All of these activities have been difficult to pursue in a laboratory setting due in part to lack of appropriate means to produce a realistic blast loading profile. © 2012 American Institute of Physics

  10. Oxy-acetylene driven laboratory scale shock tubes for studying blast wave effects

    NASA Astrophysics Data System (ADS)

    Courtney, Amy C.; Andrusiv, Lubov P.; Courtney, Michael W.

    2012-04-01

    This paper describes the development and characterization of modular, oxy-acetylene driven laboratory scale shock tubes. Such tools are needed to produce realistic blast waves in a laboratory setting. The pressure-time profiles measured at 1 MHz using high-speed piezoelectric pressure sensors have relevant durations and show a true shock front and exponential decay characteristic of free-field blast waves. Descriptions are included for shock tube diameters of 27-79 mm. A range of peak pressures from 204 kPa to 1187 kPa (with 0.5-5.6% standard error of the mean) were produced by selection of the driver section diameter and distance from the shock tube opening. The peak pressures varied predictably with distance from the shock tube opening while maintaining both a true blast wave profile and relevant pulse duration for distances up to about one diameter from the shock tube opening. This shock tube design provides a more realistic blast profile than current compression-driven shock tubes, and it does not have a large jet effect. In addition, operation does not require specialized personnel or facilities like most blast-driven shock tubes, which reduces operating costs and effort and permits greater throughput and accessibility. It is expected to be useful in assessing the response of various sensors to shock wave loading; assessing the reflection, transmission, and absorption properties of candidate armor materials; assessing material properties at high rates of loading; assessing the response of biological materials to shock wave exposure; and providing a means to validate numerical models of the interaction of shock waves with structures. All of these activities have been difficult to pursue in a laboratory setting due in part to lack of appropriate means to produce a realistic blast loading profile.

  11. On Reflection of Shock Waves from Boundary Layers

    NASA Technical Reports Server (NTRS)

    Liepmann, H W; Roshko, A; Dhawan, S

    1952-01-01

    Measurements are presented at Mach numbers from about 1.3 to 1.5 of reflection characteristics and the relative upstream influence of shock waves impinging on a flat surface with both laminar and turbulent boundary layers. The difference between impulse and step waves is discussed and their interaction with the boundary layer is compared. General considerations on the experimental production of shock waves from wedges and cones and examples of reflection of shock waves from supersonic shear layers are also presented.

  12. Hugoniot equation of state of rock materials under shock compression

    NASA Astrophysics Data System (ADS)

    Zhang, Q. B.; Braithwaite, C. H.; Zhao, J.

    2017-01-01

    Two sets of shock compression tests (i.e. conventional and reverse impact) were conducted to determine the shock response of two rock materials using a plate impact facility. Embedded manganin stress gauges were used for the measurements of longitudinal stress and shock velocity. Photon Doppler velocimetry was used to capture the free surface velocity of the target. Experimental data were obtained on a fine-grained marble and a coarse-grained gabbro over a shock pressure range of approximately 1.5-12 GPa. Gabbro exhibited a linear Hugoniot equation of state (EOS) in the pressure-particle velocity (P-up) plane, while for marble a nonlinear response was observed. The EOS relations between shock velocity (US) and particle velocity (up) are linearly fitted as US = 2.62 + 3.319up and US = 5.4 85 + 1.038up for marble and gabbro, respectively. This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'.

  13. Hugoniot equation of state of rock materials under shock compression.

    PubMed

    Zhang, Q B; Braithwaite, C H; Zhao, J

    2017-01-28

    Two sets of shock compression tests (i.e. conventional and reverse impact) were conducted to determine the shock response of two rock materials using a plate impact facility. Embedded manganin stress gauges were used for the measurements of longitudinal stress and shock velocity. Photon Doppler velocimetry was used to capture the free surface velocity of the target. Experimental data were obtained on a fine-grained marble and a coarse-grained gabbro over a shock pressure range of approximately 1.5-12 GPa. Gabbro exhibited a linear Hugoniot equation of state (EOS) in the pressure-particle velocity (P-up) plane, while for marble a nonlinear response was observed. The EOS relations between shock velocity (US) and particle velocity (up) are linearly fitted as US = 2.62 + 3.319up and US = 5.4 85 + 1.038up for marble and gabbro, respectively.This article is part of the themed issue 'Experimental testing and modelling of brittle materials at high strain rates'. © 2016 The Author(s).

  14. Feshbach resonance induced shock waves in Bose-Einstein condensates.

    PubMed

    Pérez-García, Víctor M; Konotop, Vladimir V; Brazhnyi, Valeriy A

    2004-06-04

    We propose a method for generating shock waves in Bose-Einstein condensates by rapidly increasing the value of the nonlinear coefficient using Feshbach resonances. We show that in a cigar-shaped condensate there exist primary (transverse) and secondary (longitudinal) shock waves. We analyze how the shocks are generated in multidimensional scenarios and describe the related phenomenology.

  15. Addressing the problem of uniform converging spherical shock wave in water

    NASA Astrophysics Data System (ADS)

    Nitishinskiy, M.; Efimov, S.; Yanuka, D.; Gurovich, V. Tz.; Krasik, Ya. E.

    2016-10-01

    Time-resolved parameters of plasma compressed by a shock wave generated by the underwater electrical explosion of a spherical wire array are presented. The plasma was preliminarily formed inside a capillary placed at the equatorial plane along the axis of the array. Temporal evolution analysis of Hα and C II spectral lines showed that the plasma density increases from its initial value of ˜3 × 1017 cm-3 up to ˜5.5 × 1017 cm-3 within 300 ± 25 ns. These results were found to be in agreement with those of the model that considers the adiabatic compression of the plasma by the converging capillary walls caused by interaction with the incident shock wave with a pressure of ˜3 × 109 Pa at a radius of 1.5 mm. The latter results coincide well with those of the 1D hydrodynamic modeling, which assumes uniformity of the converging shock wave.

  16. Propagation of compression waves in bubbly liquid with hydrate formation

    NASA Astrophysics Data System (ADS)

    Shagapov, V. Sh.; Lepikhin, S. A.; Chiglintsev, I. A.

    2010-06-01

    The dynamics of planar one-dimensional shock waves applied to the available experimental data for the water-Freon system is studied on the basis of the theoretical model of the bubbly liquid refined with regard for a possible hydrate formation. A scheme is proposed for considering the fragmentation of bubbles in the shock wave, which is one of the main factors of the intensification of the hydrate formation process with the growth of the shock wave amplitude.

  17. Treatment protocols to reduce renal injury during shock wave lithotripsy

    PubMed Central

    McAteer, James A.; Evan, Andrew P.; Williams, James C.; Lingeman, James E.

    2010-01-01

    Purpose of review Growing concern over the acute and long-term adverse effects associated with shock wave lithotripsy calls for treatment strategies to reduce renal injury and improve the efficiency of stone breakage in shock wave lithotripsy. Recent findings Experimental studies in the pig model show that lithotripter settings for power and shock wave rate and the sequence of shock wave delivery can be used to reduce trauma to the kidney. Step-wise power ramping as is often used to acclimate the patient to shock waves causes less tissue trauma when the initial dose is followed by a brief (3–4 min) pause in shock wave delivery. Slowing the firing rate of the lithotripter to 60 shock waves/min or slower is also effective in reducing renal injury and has the added benefit of improving stone breakage outcomes. Neither strategy to reduce renal injury – not power ramping with ‘pause-protection’ nor delivering shock waves at reduced shock wave rate – have been tested in clinical trials. Summary Technique in lithotripsy is critically important, and it is encouraging that simple, practical steps can be taken to improve the safety and efficacy of shock wave lithotripsy. PMID:19195131

  18. Dynamic shear strength of S2 glass fiber reinforced polymer composites under shock compression

    NASA Astrophysics Data System (ADS)

    Yuan, Fuping; Tsai, Liren; Prakash, Vikas; Dandekar, Dattatraya P.; Rajendran, A. M.

    2008-05-01

    In the present paper, a series of plate impact shock-reshock and shock-release experiments were conducted to study the critical shear strength of a S2 glass fiber reinforced polymer (GRP) composite under shock compression levels ranging from 0.8 to 1.8 GPa. The GRP was fabricated at ARL, Aberdeen, using S2 glass woven roving in a Cycom 4102 polyester resin matrix. The experiments were conducted by using an 82.5 mm bore single-stage gas gun at Case Western Reserve University. In order to conduct shock-reshock and shock-release experiments a dual flyer plate assembly was utilized. The shock-reshock experiments were conducted by using a projectile faced with GRP and backed with a relatively high shock impedance Al 6061-T6 plate; while for the shock-release experiments the GRP was backed by a relatively lower impedance polymethyl methacrylate backup flyer plate. A multibeam velocity interferometer was used to measure the particle velocity profile at the rear surface of the target plate. By using self-consistent technique procedure described by Asay and Chabbildas [Shock Waves and High-Strain-Rate Phenomena, in Metals, edited by M. M. Myers and L. E. Murr (Plenum, New York, 1981), pp. 417-431], the critical shear strength of the GRP (2τc) was determined for impact stresses in the range of 0.8 to 1.8 GPa. The results show that the critical shear strength of the GRP is increased from 0.108 GPa to 0.682 GPa when the impact stress is increased from 0.8 to 1.8 GPa. The increase in critical shear strength may be attributed to rate-dependence and/or pressure dependent yield behavior of the GRP.

  19. Hypersonic mixed-compression inlet shock-induced combustion ramjets

    NASA Astrophysics Data System (ADS)

    Alexander, Derrick

    This study investigates the performance and flow field features of a mixed-compression inlet shock-induced combustion ramjet (shcramjet). In a shcramjet, oncoming air is compressed with shocks in the inlet and then further compressed and mixed with hydrogen fuel in a duct prior to shock-induced combustion and expansion of the combustion products through a divergent nozzle to provide thrust. Numerical studies are undertaken using the WARP code that solves the Favre-averaged Navier-Stokes equations closed by the Wilcox k-o turbulence model. Hydrogen/air combustion is solved via the twenty reaction, nine species combustion model of Jachimowski. Mixing augmentation through the use of cantilevered ramp injector arrays on opposite shcramjet inlet walls is studied and the influence of relative array locations is quantified. Increased spanwise distance between adjacent injectors on opposite walls allows for increased jet penetration and fuel distributions in the center of the engine duct. Chemically reacting studies verify an air buffer is created between the fuel and walls that suppresses premature ignition while still allowing for an air based mixing efficiency of up to 0.46-0.54. Combustion is produced over aerodynamic wedges with the spatial flow variation dictating both detonation and shock-induced combustion can be present over constant angle wedges. The initial inlet angle must be as high as possible, while avoiding premature ignition, to generate the pressure in the combustor needed for significant positive thrust. Thrust production from combustion is found to be insensitive to wedge angle if combustion is initiated across the cross-sectional area. Strong recirculation regions are formed via shock/boundary layer interactions in the confined engine duct. Mitigation of the recirculation is demonstrated with correct placement of the nozzle expansion in conjunction with air blowing in the boundary layer at a mass flow rate on the order of that of the fuel injection

  20. Control and reduction of unsteady pressure loads in separated shock wave turbulent boundary layer interaction

    NASA Technical Reports Server (NTRS)

    Dolling, David S.; Barter, John W.

    1995-01-01

    The focus was on developing means of controlling and reducing unsteady pressure loads in separated shock wave turbulent boundary layer interactions. Section 1 describes how vortex generators can be used to effectively reduce loads in compression ramp interaction, while Section 2 focuses on the effects of 'boundary-layer separators' on the same interaction.

  1. Amorphization and nanocrystallization of silcon under shock compression

    DOE PAGES

    Remington, B. A.; Wehrenberg, C. E.; Zhao, S.; ...

    2015-11-06

    High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon unveiled remarkable structural changes above a pressure threshold. Two distinct amorphous regions were identified: (a) a bulk amorphous layer close to the surface and (b) amorphous bands initially aligned with {111} slip planes. Further increase of the laser energy leads to the re-crystallization of amorphous silicon into nanocrystals with high concentration of nano-twins. This amorphization is produced by the combined effect of high magnitude hydrostatic and shear stresses under dynamic shock compression. Shock-induced defects play a very important role in the onset of amorphization. Calculations of the free energymore » changes with pressure and shear, using the Patel-Cohen methodology, are in agreement with the experimental results. Molecular dynamics simulation corroborates the amorphization, showing that it is initiated by the nucleation and propagation of partial dislocations. As a result, the nucleation of amorphization is analyzed qualitatively by classical nucleation theory.« less

  2. Development of shock wave assisted therapeutic devices and establishment of shock wave therapy.

    PubMed

    Hosseini, S H R; Menezes, V; Moosavi-Nejad, S; Ohki, T; Nakagawa, A; Tominaga, T; Takayama, K

    2006-01-01

    In order to exploit systems for shock wave therapy, we are working for the development of clinical devices that are based on the concept of shock waves or related phenomena. The paper describes these new therapeutic devices designed for the minimally invasive approach to vascular thromboloysis, selective dissection of tissues, and drug or DNA delivery. To investigate the response of cells to shock loading, a precise method of shock waves generation in space and time has been developed. This method has been studied for application in cardiovascular therapy, cancer treatment, and cranioplasty in close vicinity of the brain. A laser ablation shock wave assisted particle acceleration device has been developed for delivering drug and DNA into soft targets in the human body. The penetration depth of microparticles observed in the experimental targets is believed to be sufficient for pharmacological treatments. In order to achieve an efficient method for rapid revascularization of cerebral thrombosis, a laser induced liquid jet (LILJ) system has been developed. The LILJ has been successfully applied for selective dissection of soft tissue preserving nerve and blood vessels. The system has been further improved by using piezoelectric actuators to drive the liquid jets, as an alternative to pulse laser.

  3. X-ray Thomson scattering measurements from shock-compressed deuterium

    SciTech Connect

    Davis, P.; Doeppner, T.; Rygg, J. R.; Fortmann, C.; Unites, W.; Salmonson, J.; Collins, G. W.; Landen, O. L.; Falcone, R. W.; Glenzer, S. H.

    2012-05-25

    X-ray Thomson scattering has recently been shown to be an effective method of diagnosing a variety of high energy density plasma conditions. We apply this powerful technique to the widely studied problem of shock-compressed liquid deuterium. The behavior of deuterium under extreme conditions has received considerable attention due to its central role in models of giant planets and the importance of the high-pressure insulator-metal transition. We have used spectrally resolved x-ray scattering from electron-plasma waves to perform microscopic observations of ionization during compression. In these experiments, a single shock was launched in cryogenic deuterium reaching compressions of 3x. The 2 keV Ly-{alpha} line in silicon was used as an x-ray source in a forward scattering geometry. In addition to elastic scattering from tightly bound electrons, this low probe energy accessed the collective plasmon oscillations of delocalized electrons. Inelastic scattering from the plasmons allowed accurate measurements of the free electron density through the spectral position of the resonance and provided an estimate of the temperature through its ratio with the elastic feature. Combined with velocity interferometry from the reflective shock front, this lead to a direct determination of the ionization state. We compare the measured ionization conditions with computational models. Additionally, we discuss the possibility of using this technique to determine electrical conductivity and to directly observe pressure-induced molecular dissociation along the Hugoniot.

  4. Direct Visualization of Shock Waves in Supersonic Space Shuttle Flight

    NASA Technical Reports Server (NTRS)

    OFarrell, J. M.; Rieckhoff, T. J.

    2011-01-01

    Direct observation of shock boundaries is rare. This Technical Memorandum describes direct observation of shock waves produced by the space shuttle vehicle during STS-114 and STS-110 in imagery provided by NASA s tracking cameras.

  5. EXPERIMENTAL STUDY OF SHOCK WAVE DYNAMICS IN MAGNETIZED PLASMAS

    SciTech Connect

    Nirmol K. Podder

    2009-03-17

    In this four-year project (including one-year extension), the project director and his research team built a shock-wave-plasma apparatus to study shock wave dynamics in glow discharge plasmas in nitrogen and argon at medium pressure (1–20 Torr), carried out various plasma and shock diagnostics and measurements that lead to increased understanding of the shock wave acceleration phenomena in plasmas. The measurements clearly show that in the steady-state dc glow discharge plasma, at fixed gas pressure the shock wave velocity increases, its amplitude decreases, and the shock wave disperses non-linearly as a function of the plasma current. In the pulsed discharge plasma, at fixed gas pressure the shock wave dispersion width and velocity increase as a function of the delay between the switch-on of the plasma and shock-launch. In the afterglow plasma, at fixed gas pressure the shock wave dispersion width and velocity decrease as a function of the delay between the plasma switch-off and shock-launch. These changes are found to be opposite and reversing towards the room temperature value which is the initial condition for plasma ignition case. The observed shock wave properties in both igniting and afterglow plasmas correlate well with the inferred temperature changes in the two plasmas.

  6. Mechanochemistry for Shock Wave Energy Dissipation

    NASA Astrophysics Data System (ADS)

    Shaw, William; Ren, Yi; Su, Zhi; Moore, Jeffrey; Suslick, Kenneth; Dlott, Dana

    2015-06-01

    Using our laser-driven flyer-plate apparatus we have developed a technique for detecting mechanically driven chemical reactions that attenuate shock waves. In these experiments 75 μm laser-driven flyer-plates travel at speeds of up to 2.8 km/s. Photonic Doppler velocimetry is used to monitor both the flight speed and the motions of an embedded mirror behind the sample on the supporting substrate. Since the Hugoniot of the substrate is known, mirror motions can be converted into the transmitted shock wave flux and fluence through a sample. Flux shows the shock profile whereas fluence represents the total energy transferred per unit area, and both are measured as a function of sample thickness. Targets materials are micrograms of carefully engineered organic and inorganic compounds selected for their potential to undergo negative volume, endothermic reactions. In situ fluorescence measurements and a suite of post mortem analytical methods are used to detect molecular chemical reactions that occur due to impact.

  7. Modeling Propagation of Shock Waves in Metals

    SciTech Connect

    Howard, W M; Molitoris, J D

    2005-08-19

    We present modeling results for the propagation of strong shock waves in metals. In particular, we use an arbitrary Lagrange Eulerian (ALE3D) code to model the propagation of strong pressure waves (P {approx} 300 to 400 kbars) generated with high explosives in contact with aluminum cylinders. The aluminum cylinders are assumed to be both flat-topped and have large-amplitude curved surfaces. We use 3D Lagrange mechanics. For the aluminum we use a rate-independent Steinberg-Guinan model, where the yield strength and shear modulus depend on pressure, density and temperature. The calculation of the melt temperature is based on the Lindermann law. At melt the yield strength and shear modulus is set to zero. The pressure is represented as a seven-term polynomial as a function of density. For the HMX-based high explosive, we use a JWL, with a program burn model that give the correct detonation velocity and C-J pressure (P {approx} 390 kbars). For the case of the large-amplitude curved surface, we discuss the evolving shock structure in terms of the early shock propagation experiments by Sakharov.

  8. Investigating Vaporization of Silica through Laser Driven Shock Wave Experiments

    NASA Astrophysics Data System (ADS)

    Kraus, R. G.; Swift, D. C.; Stewart, S. T.; Smith, R.; Bolme, C. A.; Spaulding, D. K.; Hicks, D.; Eggert, J.; Collins, G.

    2010-12-01

    Giant impacts melt and vaporize a significant amount of the bolide and target body. However, our ability to determine how much melt or vapor a given impact creates depends strongly on our understanding of the liquid-vapor phase boundary of geologic materials. Our current knowledge of the liquid-vapor equilibrium for one of the most important minerals, SiO2, is rather limited due to the difficulty of performing experiments in this area of phase space. In this study, we investigate the liquid-vapor coexistence region by shocking quartz into a supercritical fluid state and allowing it to adiabatically expand to a state on the liquid-vapor phase boundary. Although shock compression and release has been used to study the liquid-vapor equilibrium of metals [1], few attempts have been made at studying geologic materials by this method [2]. Shock waves were produced by direct ablation of the quartz sample using the Jupiter Laser Facility of Lawrence Livermore National Laboratory. Steady shock pressures of 120-360 GPa were produced in the quartz samples: high enough to force the quartz into a supercritical fluid state. As the shock wave propagates through the sample, we measure the shock velocity using a line imaging velocity interferometer system for any reflector (VISAR) and shock temperature using a streaked optical pyrometer (SOP). When the shock wave reaches the free surface of the sample, the material adiabatically expands. Upon breakout of the shock at the free surface, the SOP records a distinct drop in radiance due to the lower temperature of the expanded material. For a subset of experiments, a LiF window is positioned downrange of the expanding silica. When the expanding silica impacts the LiF window, the velocity at the interface between the expanding silica and LiF window is measured using the VISAR. From the shock velocity measurements, we accurately determine the shocked state in the quartz. The post-shock radiance measurements are used to constrain the

  9. Measurement of sound velocities in shock-compressed tin under pressures up to 150 GPa

    NASA Astrophysics Data System (ADS)

    Zhernokletov, Mikhail; Kovalev, Alexey; Komissarov, Vladimir; Zocher, Marvin; Cherne, Frank

    2009-06-01

    Tin has a complex phase diagram, which can be explained by presence of structural phase transitions. The fracture in the dependence of sound velocity on pressure is caused by structural transitions in shock-compressed substance. Therefore, basing on measurement of sound velocities, it is possible to reveal phase transitions of substance along shock adiabat, including its melting. The results of different authors give the melting range of tin from 35 up to 93 GPa. In this work tin samples with initial density of 7.28 g/cm^3 were loaded with use of HE-based generators of shock waves. In the pressure range of 30-150 GPa, sound velocity in tin was measured by the method of overtaking release with use of the optical gauges and the indicator liquids: carbogal, tetrachlormethane, and bromoform. Up to shock compression pressures of about 35 GPa, sound velocity was measured by the method of oncoming release with use of piezoresistive manganin-based gauges. The obtained data testifies that the melting range of tin is ˜6390 GPa.

  10. X-ray Scattering Measurement of the Heat Capacity Ratio in Shock Compressed Matter

    NASA Astrophysics Data System (ADS)

    Fortmann, C.; Lee, H. J.; Doeppner, Tilo; Kritcher, A. L.; Landen, O. L.; Falcone, R. W.; Glenzer, S. H.

    2011-10-01

    We developed accurate x-ray scattering techniques to measure properties of matter under extreme conditions of density and temperature in intense laser-solid interaction experiments. We report on novel applications of x-ray scattering to measure the heat-capacity ratio γ =cp /cv of a Be plasma which determines the equation of state of the system. Ultraintense laser radiation is focussed onto both sides of a Be foil, creating two counterpropagating planar shock waves that collide in the target center. A second set of lasers produces Zn He- α radiation of 8.9 keV energy that scatters from the shock-compressed matter. We observe temperatures of 10eV and 15eV and mass densities of 5g/cm3 and 11g/cm3 before and after the shock collision. Applying the Rankine-Hugoniot relations for counterpropagating shocks we then infer γ as a function of density using only the measured mass compression ratios. Our results agree with equation of state models and DFT simulations. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. We acknowledge support from the Alexander von Humboldt-Foundation.

  11. A numerical study of shock wave diffraction by a circular cylinder

    NASA Technical Reports Server (NTRS)

    Yang, J.-Y.; Liu, Y.; Lomax, H.

    1986-01-01

    The nonstationary shock wave diffraction patterns generated by a blast wave impinging on a circular cylinder are numerically simulated using a second-order hybrid upwind method for solving the two-dimensional inviscid compressible Euler equations of gasdynamics. The complete diffraction patterns, including the transition from regular to Mach reflection, trajectory of the Mach triple point and the complex shock-on-shock interaction at the wake region resulting from the Mach shocks collision behind the cylinder are reported in detail. Pressure-time history and various contour plots are also included. Comparison between the work of Bryson and Gross (1961) which included both experimental schlieren pictures and theoretical calculations using Whitham's ray-shock theory and results of the present finite difference computation indicate good agreement in every aspect except for some nonideal gas and viscous effects which are not accounted for by the Euler equations.

  12. A numerical study of shock wave diffraction by a circular cylinder

    NASA Technical Reports Server (NTRS)

    Yang, J.-Y.; Liu, Y.; Lomax, H.

    1986-01-01

    The nonstationary shock wave diffraction patterns generated by a blast wave impinging on a circular cylinder are numerically simulated using a second-order hybrid upwind method for solving the two-dimensional inviscid compressible Euler equations of gasdynamics. The complete diffraction patterns, including the transition from regular to Mach reflection, trajectory of the Mach triple point and the complex shock-on-shock interaction at the wake region resulting from the Mach shocks collision behind the cylinder are reported in detail. Pressure-time history and various contour plots are also included. Comparison between the work of Bryson and Gross (1961) which included both experimental schlieren pictures and theoretical calculations using Whitham's ray-shock theory and results of the present finite difference computation indicate good agreement in every aspect except for some nonideal gas and viscous effects which are not accounted for by the Euler equations.

  13. Underwater Shock Wave Research Applied to Therapeutic Device Developments

    NASA Astrophysics Data System (ADS)

    Takayama, K.; Yamamoto, H.; Shimokawa, H.

    2013-07-01

    The chronological development of underwater shock wave research performed at the Shock Wave Research Center of the Institute of Fluid Science at the Tohoku University is presented. Firstly, the generation of planar underwater shock waves in shock tubes and their visualization by using the conventional shadowgraph and schlieren methods are described. Secondly, the generation of spherical underwater shock waves by exploding lead azide pellets weighing from several tens of micrograms to 100 mg, that were ignited by irradiating with a Q-switched laser beam, and their visualization by using double exposure holographic interferometry are presented. The initiation, propagation, reflection, focusing of underwater shock waves, and their interaction with various interfaces, in particular, with air bubbles, are visualized quantitatively. Based on such a fundamental underwater shock wave research, collaboration with the School of Medicine at the Tohoku University was started for developing a shock wave assisted therapeutic device, which was named an extracorporeal shock wave lithotripter (ESWL). Miniature shock waves created by irradiation with Q-switched HO:YAG laser beams are studied, as applied to damaged dysfunctional nerve cells in the myocardium in a precisely controlled manner, and are effectively used to design a catheter for treating arrhythmia.

  14. Early-Stage Acceleration of SEPs by CME-Driven Shocks and Compressions

    NASA Astrophysics Data System (ADS)

    Kozarev, K. A.; Schwadron, N.; Keith, C.; Kendrick, A.; Davey, A. R.

    2016-12-01

    Most Coronal Mass Ejections (CMEs) exhibit a typical three-stage kinematic profile from their onset until about 5 Rs. It consists of an initial relatively slow onset very low in the corona, followed by a period of rapid acceleration and expansion, and a final period when their speed adjusts to the surrounding solar wind speed and their expansion slows down. Most of the Solar Energetic Particle (SEP) acceleration associated with the CME evolution is expected to occur during these three stages, especially the second one, when CMEs may drive plasma pile-up compressions and shocks. However, the lack of in situ observations near the Sun requires the use of indirect methods for constraining the acceleration. We review recent techniques for assessing the SEP acceleration efficiency of early-stage CME-driven compressive waves. The relevant parameters may be obtained from EUV, white light, and radio observations in combination with models for the coronal magnetic field, plasma density and temperature. EUV imaging with the Atmospheric Imaging Assembly (AIA) instrument on the Solar Dynamics Observatory spacecraft has proven particularly useful for detecting large-scale short-lived coronal bright fronts. We have take a further step, and applied analytic and numerical models of diffusive shock acceleration of protons in several large-scale plasma compressive fronts. We present the modeling results of acceleration efficiency and extent in this dynamic region near the Sun, for several cases of CME kinematic profiles, and demonstrate in detail the intimate connection between SEP production and compression/shock evolution. Comprehensive understanding of where and when CMEs accelerate SEPs is important for constraining the heliospheric populations and to improve the mitigation of space radiation; understanding CME-driven shock acceleration near the Sun is a crucial piece of this puzzle.

  15. Surface wave tomography with compressive sensing

    NASA Astrophysics Data System (ADS)

    Zhan, Z.; Li, Q.; Huang, J.

    2016-12-01

    The development of dense seismic arrays has led to the emergence of new surface wave tomography methods, such as Eikonal/Helmholtz tomography, wavefield gradiometry, and seismic noise gradiometry. All these methods need to calculate spatial derivatives of some attributes of the wavefields, for example travel time, amplitude, or the displacement itself. Usually, the waveforms contain noise and are observed on an irregular grid. Interpolation and smoothing are necessary to mitigate the problems, but also limit the resolution of tomography. Here, we propose a new data pre-processing method based on compressive sensing (CS). The new method uses sparsity promoting inverse techniques and curvelet transform to achieve simultaneous seismic data interpolation and denoising in frequency domain. The resulted wavefields can then be used in any wavefield-based surface wave tomography method. Preliminary tests with finite-difference synthetics show improved tomographic images, compared with images from the same methods applied to the original synthetics.

  16. Detonation wave compression in gas turbines

    NASA Technical Reports Server (NTRS)

    Wortman, A.

    1986-01-01

    A study was made of the concept of augmenting the performance of low pressure ratio gas turbines by detonation wave compression of part of the flow. The concept exploits the constant volume heat release of detonation waves to increase the efficiency of the Brayton cycle. In the models studied, a fraction of the compressor output was channeled into detonation ducts where it was processed by transient transverse detonation waves. Gas dynamic studies determined the maximum cycling frequency of detonation ducts, proved that upstream propagation of pressure pulses represented no problems and determined the variations of detonation duct output with time. Mixing and wave compression were used to recombine the combustor and detonation duct flows and a concept for a spiral collector to further smooth the pressure and temperature pulses was presented as an optional component. The best performance was obtained with a single firing of the ducts so that the flow could be re-established before the next detonation was initiated. At the optimum conditions of maximum frequency of the detonation ducts, the gas turbine efficiency was found to be 45 percent while that of a corresponding pressure ratio 5 conventional gas turbine was only 26%. Comparable improvements in specific fuel consumption data were found for gas turbines operating as jet engines, turbofans, and shaft output machines. Direct use of the detonation duct output for jet propulsion proved unsatisfactory. Careful analysis of the models of the fluid flow phenomena led to the conclusion that even more elaborate calculations would not diminish the uncertainties in the analysis of the system. Feasibility of the concept to work as an engine now requires validation in an engineering laboratory experiment.

  17. Particle Acceleration in SN1006 Shock Waves

    NASA Technical Reports Server (NTRS)

    Raymond, John C.; Ghavamian, Parviz; Sonneborn, George (Technical Monitor)

    2003-01-01

    This grant is for the analysis of FUSE observations of particle acceleration in supernova remnant SN1006 shock waves. We have performed quick look analysis of the data, but because the source is faint and because the O VI emission lines on SN1006 are extremely broad, extreme care is needed for background subtraction and profile fitting. Moreover, the bulk of the analysis in will consist of model calculations. The Ly beta and O VI lines are clearly detected at the position in the NW filament of SN1006, but not in the NE position where non-thermal X-rays are strong. The lack of O VI emission in the NE places an upper limit on the pre-shock density there.

  18. Nonplanar electrostatic shock waves in dense plasmas

    SciTech Connect

    Masood, W.; Rizvi, H.

    2010-02-15

    Two-dimensional quantum ion acoustic shock waves (QIASWs) are studied in an unmagnetized plasma consisting of electrons and ions. In this regard, a nonplanar quantum Kadomtsev-Petviashvili-Burgers (QKPB) equation is derived using the small amplitude perturbation expansion method. Using the tangent hyperbolic method, an analytical solution of the planar QKPB equation is obtained and subsequently used as the initial profile to numerically solve the nonplanar QKPB equation. It is observed that the increasing number density (and correspondingly the quantum Bohm potential) and kinematic viscosity affect the propagation characteristics of the QIASW. The temporal evolution of the nonplanar QIASW is investigated both in Cartesian and polar planes and the results are discussed from the numerical stand point. The results of the present study may be applicable in the study of propagation of small amplitude localized electrostatic shock structures in dense astrophysical environments.

  19. Electrohydraulic shock wave generation as a means to increase intrinsic permeability of mortar

    SciTech Connect

    Maurel, O.; Reess, T.; Matallah, M.; De Ferron, A.; Chen, W.; La Borderie, C.; Pijaudier-Cabot, G.; Jacques, A.; Rey-Bethbeder, F.

    2010-12-15

    This article discusses the influence of compressive shock waves on the permeability of cementitious materials. Shock waves are generated in water by Pulsed Arc Electrohydraulic Discharges (PAED). The practical aim is to increase the intrinsic permeability of the specimens. The maximum pressure amplitude of the shock wave is 250 MPa. It generates damage in the specimens and the evolution of damage is correlated with the intrinsic permeability of the mortar. A threshold of pressure is observed. From this threshold, the increase of permeability is linear in a semi-log plot. The influence of repeated shocks on permeability is also discussed. Qualitative X Ray Tomography illustrates the evolution of the microstructure of the material leading to the increase of permeability. Comparative results from mercury intrusion porosimetry (MIP) show that the micro-structural damage process starts at the sub-micrometric level and that the characteristic size of pores of growing volume increases.

  20. Planar and nonplanar ion acoustic shock waves in relativistic degenerate astrophysical electron-positron-ion plasmas

    SciTech Connect

    Ata-ur-Rahman,; Qamar, A.; Ali, S.; Mirza, Arshad M.

    2013-04-15

    We have studied the propagation of ion acoustic shock waves involving planar and non-planar geometries in an unmagnetized plasma, whose constituents are non-degenerate ultra-cold ions, relativistically degenerate electrons, and positrons. By using the reductive perturbation technique, Korteweg-deVries Burger and modified Korteweg-deVries Burger equations are derived. It is shown that only compressive shock waves can propagate in such a plasma system. The effects of geometry, the ion kinematic viscosity, and the positron concentration are examined on the ion acoustic shock potential and electric field profiles. It is found that the properties of ion acoustic shock waves in a non-planar geometry significantly differ from those in planar geometry. The present study has relevance to the dense plasmas, produced in laboratory (e.g., super-intense laser-dense matter experiments) and in dense astrophysical objects.

  1. Electrical Conductivity of Shock-Compressed PVDF Films

    NASA Astrophysics Data System (ADS)

    Yakushev, V. V.; Yakusheva, T. I.

    1997-07-01

    Time-dependent conductivity measurements on shocked PVDF films were made using flyer plate impact experiments in the range of 4.6 to 23 GPa. Two types of PVDF films were investigated. They were a 30-micron uni-axially-stretched modified PVDF film (4Plastpolymer Okhta Research and Production Association of Russia and a 25-micron bi-axially-stretched PVDF film from Solvay, Belgium. Gauge arrangements with 5-mm square active areas and patterns similar to those used by Bauer of ISL, France, were produced and mounted in Teflon for the tests. The conductivity experiments were performed using the PVDF gauges in the Lagrangian mode while subjecting their elements to an electrical field in the direction of shock propagatiuon. Observations were made for 1 to 2 microseconds after shock arrival. The onset of electrical conductivity was detected at 10 GPa for the uni-axially stretched film, whereas, this event was detected at approximately 13.5 GPa for the bi-axially-stretched film. At 23 GPa, the conductivity of the uni-axially stretched film was measured to be less than 1 ohm (-1) m(-1). It appears that chemical decomposition may well play a role in the observed electrical conductivity in PVDF films, an effect that should not be too surprising if one considers the very large temperatures induced by shock compression at such high pressures.

  2. Shock compression of quartz and aluminum powder mixtures

    SciTech Connect

    Joshi, V.S.; Thadhani, N.N.; Graham, R.A.; Holman, G.T. Jr.

    1996-05-01

    We report about the shock-compression response of highly porous (55{percent} and 65{percent} dense) mixtures of 4Al+3SiO{sub 2} powders having shock-induced phase transitions and chemical reactions. Shock recovery experiments were performed using the CETR/Sawaoka plate-impact system (P=40 to 100 GPa) and the Sandia Momma Bear A Comp B fixture (P=22 to 45 GPa). The recovered compacts contained the high pressure stishovite phase, products of chemical reaction, as well as unreacted constituents. The reaction products formed included Al{sub 2}O{sub 3}, metallic Si (ambient and high pressure phases), SiAl intermetallic, and kyanite (Al{sub 2}SiO{sub 5}). The shock-induced chemical reaction in 4Al+3SiO{sub 2} powder mixtures, appears to have been accompanied (or assisted) by the formation of stishovite, a high pressure phase of quartz. {copyright} {ital 1996 American Institute of Physics.}

  3. Electrostatic waves in the bow shock at Uranus

    SciTech Connect

    Moses, S.L.; Coroniti, F.V.; Kennel, C.F.; Scarf, F.L. ); Bagenal, F. ); Lepping, R.P. ); Quest, K.B. ); Kurth, W.S. )

    1989-10-01

    Electrostatic emissions measured by the Voyager 2 plasma wave detector (PWS) during the inbound crossing of the Uranian bow shock are shown to differ in some aspects from the waves measured during bow shock crossings at Jupiter and Saturn. The wave amplitudes in the foot of the bow shock at Uranus are in general much lower than those detected at the other out planets due to the unusually enhanced solar wind ion temperature during the crossing. This reduces the effectiveness of wave-particle interactions in heating the incoming electrons. Strong wave emissions are observed in the shock ramp that possibly arise from currents producing a Buneman mode instability. Plasma instrument (PLS) and magnetometer (MAG) measurements reveal a complicated shock structure reminiscent of computer simulations of high-Mach number shocks when the effects of anomalous resistivity are reduced, and are consistent with high ion temperatures restricting the growth of electrostatic waves.

  4. New Devices and Old Pitfalls in Shock Wave Therapy

    NASA Astrophysics Data System (ADS)

    Bailey, Michael R.; Matula, Thomas J.; Sapozhnikov, Oleg A.; Cleveland, Robin O.; Pishchalnikov, Yuri A.; McAteer, James A.

    2006-05-01

    Shock waves are now used to treat a variety of musculoskeletal indications and the worldwide demand for shock wave therapy (SWT) is growing rapidly. It is a concern that very little is known about the mechanisms of action of shock waves in SWT. The technology for SWT devices is little changed from that of shock wave lithotripters developed for the treatment of urinary stones. SWT devices are engineered on the same acoustics principles as lithotripters, but the targets of therapy for SWT and shock wave lithotripsy (SWL) are altogether different. For SWT to achieve its potential as a beneficial treatment modality it will be necessary to determine precisely how SWT shock waves interact with biological targets. In addition, for SWT to evolve, the future design of these devices should be approached with caution, and lithotripsy may serve as a useful model. Indeed, there is a great deal to be learned from the basic research that has guided the development of SWL.

  5. Subcritical collisionless shock waves. [in earth space plasma

    NASA Technical Reports Server (NTRS)

    Mellott, M. M.

    1985-01-01

    The development history of theoretical accounts of low Mach number collisionless shock waves is related to recent observational advancements, with attention to weaker shocks in which shock steepening is limited by dispersion and/or anomalous resistivity and whose character is primarily determined by the dispersive properties of the ambient plasma. Attention has focused on nearly perpendicular shocks where dispersive scale lengths become small and the associated cross-field currents become strong enough to generate significant plasma wave turbulence. A number of oblique, low Mach number bow shocks have been studied on the basis of data from the ISEE dual spacecraft pair, allowing an accurate determination of shock scale lengths.

  6. Tension of Liquids by Shock Waves

    NASA Astrophysics Data System (ADS)

    Utkin, Alexander V.; Sosikov, Vasiliy A.; Bogach, Andrey A.; Fortov, Vladimir E.

    2004-07-01

    The influences of strain rate and initial temperature on the negative pressure in distillate water, hexane, glycerol and methyl alcohol under shock waves have been investigated. The wave profiles were registered by laser interferometer VISAR. Shock waves were produced by aluminum plates accelerated by high explosive up to 600 m/s. At initial temperature 19 °C spall strength of water, hexane, and methyl alcohol is equal to 45, 15, and 47 MPa respectively and not depend on the strain rate in interval from 10-4 to 10-5 1/s. A strong dependence of negative pressure on strain rate was observed only for glycerol. The reason is that the initial temperature of glycerol was equal to the freezing point, and in the vicinity of it the relaxation properties are usually very much more pronounced. To confirm this assumption the experiments with water an initial temperature 0.7 °C were made and strong influence of strain rate on spall strength was observed close to freezing temperature too. Moreover expansion isentropes intersected the melting curve at negative pressure and double metastable state was realized in water. Theory of homogeneous bubble nucleation was used to explain the experimental results.

  7. Local stability analysis for a planar shock wave

    NASA Technical Reports Server (NTRS)

    Salas, M. D.

    1984-01-01

    A procedure to study the local stability of planar shock waves is presented. The procedure is applied to a Rankine-Hugoniot shock in a divergent/convergent nozzle, to an isentropic shock in a divergent/convergent nozzle, and to Rankine-Hugoniot shocks attached to wedges and cones. It is shown that for each case, the equation governing the shock motion is equivalent to the damped harmonic oscillator equation.

  8. Supersonic shock wave/vortex interaction

    NASA Technical Reports Server (NTRS)

    Settles, G. S.; Cattafesta, L.

    1993-01-01

    Although shock wave/vortex interaction is a basic and important fluid dynamics problem, very little research has been conducted on this topic. Therefore, a detailed experimental study of the interaction between a supersonic streamwise turbulent vortex and a shock wave was carried out at the Penn State Gas Dynamics Laboratory. A vortex is produced by replaceable swirl vanes located upstream of the throat of various converging-diverging nozzles. The supersonic vortex is then injected into either a coflowing supersonic stream or ambient air. The structure of the isolated vortex is investigated in a supersonic wind tunnel using miniature, fast-response, five-hole and total temperature probes and in a free jet using laser Doppler velocimetry. The cases tested have unit Reynolds numbers in excess of 25 million per meter, axial Mach numbers ranging from 2.5 to 4.0, and peak tangential Mach numbers from 0 (i.e., a pure jet) to about 0.7. The results show that the typical supersonic wake-like vortex consists of a non-isentropic, rotational core, where the reduced circulation distribution is self similar, and an outer isentropic, irrotational region. The vortex core is also a region of significant turbulent fluctuations. Radial profiles of turbulent kinetic energy and axial-tangential Reynolds stress are presented. The interactions between the vortex and both oblique and normal shock waves are investigated using nonintrusive optical diagnostics (i.e. schlieren, planar laser scattering, and laser Doppler velocimetry). Of the various types, two Mach 2.5 overexpanded-nozzle Mach disc interactions are examined in detail. Below a certain vortex strength, a 'weak' interaction exists in which the normal shock is perturbed locally into an unsteady 'bubble' shock near the vortex axis, but vortex breakdown (i.e., a stagnation point) does not occur. For stronger vortices, a random unsteady 'strong' interaction results that causes vortex breakdown. The vortex core reforms downstream of

  9. Effects of Surf Zone Sediment Properties on Shock Wave Behavior

    DTIC Science & Technology

    2016-06-07

    SEP 1999 2. REPORT TYPE 3. DATES COVERED 00-00-1999 to 00-00-1999 4. TITLE AND SUBTITLE Effects of Surf Zone Sediment Properties on Shock Wave ...Effects of Surf Zone Sediment Properties on Shock Wave Behavior L. Dale Bibee Seafloor Geosciences – Code 7432 Naval Research Laboratory Stennis...mines is critically dependent upon the propagation effectiveness of shock waves from the charge to the mine. Data and modeling show that this

  10. Shock waves and nucleosynthesis in type II supernovae

    NASA Technical Reports Server (NTRS)

    Aufderheide, M. B.; Baron, E.; Thielemann, F.-K.

    1991-01-01

    In the study of nucleosynthesis in type II SN, shock waves are initiated artificially, since collapse calculations do not, as yet, give self-consistent shock waves strong enough to produce the SN explosion. The two initiation methods currently used by light-curve modelers are studied, with a focus on the peak temperatures and the nucleosynthetic yields in each method. The various parameters involved in artificially initiating a shock wave and the effects of varying these parameters are discussed.

  11. Internal energy relaxation in shock wave structure

    SciTech Connect

    Josyula, Eswar Suchyta, Casimir J.; Boyd, Iain D.; Vedula, Prakash

    2013-12-15

    The Wang Chang-Uhlenbeck (WCU) equation is numerically integrated to characterize the internal structure of Mach 3 and Mach 5 shock waves in a gas with excitation in the internal energy states for the treatment of inelastic collisions. Elastic collisions are modeled with the hard sphere collision model and the transition rates for the inelastic collisions modified appropriately using probabilities based on relative velocities of the colliding particles. The collision integral is evaluated by the conservative discrete ordinate method [F. Tcheremissine, “Solution of the Boltzmann kinetic equation for high-speed flows,” Comput. Math. Math. Phys. 46, 315–329 (2006); F. Cheremisin, “Solution of the Wang Chang-Uhlenbeck equation,” Dokl. Phys. 47, 487–490 (2002)] developed for the Boltzmann equation. For the treatment of the diatomic molecules, the internal energy modes in the Boltzmann equation are described quantum mechanically given by the WCU equation. As a first step in the treatment of the inelastic collisions by the WCU equation, a two- and three-quantum system is considered to study the effect of the varying of (1) the inelastic cross section and (2) the energy gap between the quantum energy states. An alternative method, the direct simulation Monte Carlo method, is used for the Mach 3 shock wave to ensure the consistency of implementation in the two methods and there is an excellent agreement between the two methods. The results from the WCU implementation showed consistent trends for the Mach 3 and Mach5 standing shock waves simulations. Inelastic contributions change the downstream equilibrium state and allow the flow to transition to the equilibrium state further upstream.

  12. Current topics in shock waves; Proceedings of the International Symposium on Shock Waves and Shock Tubes, 17th, Lehigh University, Bethlehem, PA, July 17-21, 1989

    NASA Astrophysics Data System (ADS)

    Kim, Yong W.

    Various papers on shock waves are presented. The general topics addressed include: shock formation, focusing, and implosion; shock reflection and diffraction; turbulence; laser-produced plasmas and waves; ionization and shock-plasma interaction; chemical kinetics, pyrolysis, and soot formation; experimental facilities, techniques, and applications; ignition of detonation and combustion; particle entrainment and shock propagation through particle suspension; boundary layers and blast simulation; computational methods and numerical simulation.

  13. Current topics in shock waves; Proceedings of the International Symposium on Shock Waves and Shock Tubes, 17th, Lehigh University, Bethlehem, PA, July 17-21, 1989

    SciTech Connect

    Kim, Y.W.

    1990-01-01

    Various papers on shock waves are presented. The general topics addressed include: shock formation, focusing, and implosion; shock reflection and diffraction; turbulence; laser-produced plasmas and waves; ionization and shock-plasma interaction; chemical kinetics, pyrolysis, and soot formation; experimental facilities, techniques, and applications; ignition of detonation and combustion; particle entrainment and shock propagation through particle suspension; boundary layers and blast simulation; computational methods and numerical simulation.

  14. On the interplay between cosmological shock waves and their environment

    NASA Astrophysics Data System (ADS)

    Martin-Alvarez, Sergio; Planelles, Susana; Quilis, Vicent

    2017-05-01

    Cosmological shock waves are tracers of the thermal history of the structures in the Universe. They play a crucial role in redistributing the energy within the cosmic structures and are also amongst the main ingredients of galaxy and galaxy cluster formation. Understanding this important function requires a proper description of the interplay between shocks and the different environments where they can be found. In this paper, an Adaptive Mesh Refinement (AMR) Eulerian cosmological simulation is analysed by means of a shock-finding algorithm that allows to generate shock wave maps. Based on the population of dark matter halos and on the distribution of density contrast in the simulation, we classify the shocks in five different environments. These range from galaxy clusters to voids. The shock distribution function and the shocks power spectrum are studied for these environments dynamics. We find that shock waves on different environments undergo different formation and evolution processes, showing as well different characteristics. We identify three different phases of formation, evolution and dissipation of these shock waves, and an intricate migration between distinct environments and scales. Shock waves initially form at external, low density regions and are merged and amplified through the collapse of structures. Shock waves and cosmic structures follow a parallel evolution. Later on, shocks start to detach from them and dissipate. We also find that most of the power that shock waves dissipate is found at scales of k ˜0.5 Mpc^{-1}, with a secondary peak at k ˜8 Mpc^{-1}. The evolution of the shocks power spectrum confirms that shock waves evolution is coupled and conditioned by their environment.

  15. DDT modeling and shock compression experiments of porous or damaged energetic materials

    SciTech Connect

    Baer, M.R.; Anderson, M.U.; Graham, R.A.

    1994-05-01

    In this presentation, we present modeling of DDT in porous energetic materials and experimental studies of a time-resolved, shock compression of highly porous inert and reactive materials. This combined theoretical and experimental studies explore the nature of the microscale processes of consolidation, deformation and reaction which are key features of the shock response of porous or damaged energetic materials. The theoretical modeling is based on the theory of mixtures in which multiphase mixtures are treated in complete nonequilibrium allowing for internal boundary effects associated mass/momentum and energy exchange between phases, relative flow, rate-dependent compaction behavior, multistage chemistry and interphase boundary effects. Numerous studies of low-velocity impacts using a high resolution adaptive finite element method are presented which replicate experimental observations. The incorporation of this model into multi-material hydrocode analysis will be discussed to address the effects of confinement and its influence on accelerated combustion behavior. The experimental studies will focus on the use of PVDF piezoelectric polymer stress-rate gauge to precisely measure the input and propagating shock stress response of porous materials. In addition to single constituent porous materials, such as granular HMX, we have resolved shock waves in porous composite intermetallic powders that confirm a dispersive wave nature which is highly morphologically and material dependent. This document consists of viewgraphs from the poster session.

  16. Confinement effects of shock waves on laser-induced plasma from a graphite target

    SciTech Connect

    Huang, Feiling; Liang, Peipei; Yang, Xu; Cai, Hua; Wu, Jiada; Xu, Ning; Ying, Zhifeng; Sun, Jian

    2015-06-15

    The spatial confinement effects of shock waves on the laser-induced plasma (LIP) from a graphite target in air were studied by probe beam deflection (PBD) measurements and optical emission spectroscopy (OES). A clear relationship between the confinement of the LIP by the shock wave and the effects on the LIP emission was observed, and the underlying mechanisms are discussed. PBD monitoring revealed that the laser-ablation induced shock wave could be well analogized to the shock wave generated by a point explosion and would be reflected by a block. OES measurements indicated that the optical emission of the LIP exhibited significant variations with the block placement. A first enhancement and then a fast decay of CN molecular emission as well as a suppression of carbon atomic emission were observed in the presence of the block. The results revealed that the reflected shock wave spatially confined the expansion of the LIP and compressed the LIP after encountering it, pushing back the species of the LIP and changing the density of the LIP species including luminous carbon atoms and CN molecules. It is suggested that the change of the LIP emission is attributed to the density variation of the LIP species due to the compression of the LIP and the reactions occurring in the plasma.

  17. Data compression for the Cassini radio and plasma wave instrument

    NASA Technical Reports Server (NTRS)

    Farrell, W. M.; Gurnett, D. A.; Kirchner, D. L.; Kurth, W. S.; Woolliscroft, L. J. C.

    1993-01-01

    The Cassini Radio and Plasma Wave Science experiment will employ data compression to make effective use of the available data telemetry bandwidth. Some compression will be achieved by use of a lossless data compression chip and some by software in a dedicated 80C85 processor. A description of the instrument and data compression system are included in this report. Also, the selection of data compression systems and acceptability of data degradation is addressed.

  18. Biodamage via shock waves initiated by irradiation with ions.

    PubMed

    Surdutovich, Eugene; Yakubovich, Alexander V; Solov'yov, Andrey V

    2013-01-01

    Radiation damage following the ionising radiation of tissue has different scenarios and mechanisms depending on the projectiles or radiation modality. We investigate the radiation damage effects due to shock waves produced by ions. We analyse the strength of the shock wave capable of directly producing DNA strand breaks and, depending on the ion's linear energy transfer, estimate the radius from the ion's path, within which DNA damage by the shock wave mechanism is dominant. At much smaller values of linear energy transfer, the shock waves turn out to be instrumental in propagating reactive species formed close to the ion's path to large distances, successfully competing with diffusion.

  19. Magnetosonic shock wave in collisional pair-ion plasma

    SciTech Connect

    Adak, Ashish Khan, Manoranjan; Sikdar, Arnab

    2016-06-15

    Nonlinear propagation of magnetosonic shock wave has been studied in collisional magnetized pair-ion plasma. The masses of both ions are same but the temperatures are slightly different. Two fluid model has been taken to describe the model. Two different modes of the magnetosonic wave have been obtained. The dynamics of the nonlinear magnetosonic wave is governed by the Korteweg-de Vries Burgers' equation. It has been shown that the ion-ion collision is the source of dissipation that causes the Burgers' term which is responsible for the shock structures in equal mass pair-ion plasma. The numerical investigations reveal that the magnetosonic wave exhibits both oscillatory and monotonic shock structures depending on the strength of the dissipation. The nonlinear wave exhibited the oscillatory shock wave for strong magnetic field (weak dissipation) and monotonic shock wave for weak magnetic field (strong dissipation). The results have been discussed in the context of the fullerene pair-ion plasma experiments.

  20. Expansion shock waves in regularized shallow-water theory

    PubMed Central

    El, Gennady A.; Shearer, Michael

    2016-01-01

    We identify a new type of shock wave by constructing a stationary expansion shock solution of a class of regularized shallow-water equations that include the Benjamin–Bona–Mahony and Boussinesq equations. An expansion shock exhibits divergent characteristics, thereby contravening the classical Lax entropy condition. The persistence of the expansion shock in initial value problems is analysed and justified using matched asymptotic expansions and numerical simulations. The expansion shock's existence is traced to the presence of a non-local dispersive term in the governing equation. We establish the algebraic decay of the shock as it is gradually eroded by a simple wave on either side. More generally, we observe a robustness of the expansion shock in the presence of weak dissipation and in simulations of asymmetric initial conditions where a train of solitary waves is shed from one side of the shock. PMID:27279780

  1. Expansion shock waves in regularized shallow-water theory

    NASA Astrophysics Data System (ADS)

    El, Gennady A.; Hoefer, Mark A.; Shearer, Michael

    2016-05-01

    We identify a new type of shock wave by constructing a stationary expansion shock solution of a class of regularized shallow-water equations that include the Benjamin-Bona-Mahony and Boussinesq equations. An expansion shock exhibits divergent characteristics, thereby contravening the classical Lax entropy condition. The persistence of the expansion shock in initial value problems is analysed and justified using matched asymptotic expansions and numerical simulations. The expansion shock's existence is traced to the presence of a non-local dispersive term in the governing equation. We establish the algebraic decay of the shock as it is gradually eroded by a simple wave on either side. More generally, we observe a robustness of the expansion shock in the presence of weak dissipation and in simulations of asymmetric initial conditions where a train of solitary waves is shed from one side of the shock.

  2. Compression dynamics and lattice kinetics in laser driven shocks of BCC metals using dynamic Laue diffraction

    NASA Astrophysics Data System (ADS)

    Wehrenberg, Christopher

    2013-10-01

    Laue diffraction experiments were used to directly observe the strain relaxation process in Ta shock compressed along the [001] direction. The unit cell aspect ratio was measured from Laue patterns at times ranging 0.1 to 1.6 ns relative to the shock wave entering the Ta sample. For 50 GPa shocks, the aspect ratio increases asymptotically to a value of 0.95 over the course of ~1 ns. The 1 ns time scale is on the order of predictions of the relaxation time scale made using the Livermore multiscale strength model [Rudd, R SCCM 2011]. In contrast, ultra-fast (less than 10 ps) relaxation times are expected above the homogeneous nucleation threshold. Consistent with this behavior, Ta subjected to shocks at 90 GPa relaxes faster than the resolution of the diffraction experiments (approximately 150 ps). As the relaxation time will be dependent on the dislocation density, one can infer a dislocation density behind the 50 GPa shock front. Dislocation densities estimated in this manner agree with in an order of magnitude both with predictions by the multiscale model and with residual dislocation densities observed in post-mortem samples. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  3. Cylindrically converging shock and detonation waves

    NASA Astrophysics Data System (ADS)

    Matsuo, H.

    1983-07-01

    The non-self-similar implosion of cylindrical shock and detonation waves generated by an instantaneous energy release at a cylindrical wall is analyzed theoretically by the method of integral relations. The analysis shows that as the wave propagates towards the axis, the solutions tend to approach but never reach the self-similar implosion limit. The rate of approach appears to be slower than expected, and the region of applicability of the self-similar solution appears to be restricted to a very small region behind the front. This tendency is more pronounced for the detonation case. It is also demonstrated that for detonations where the initiation energy is negligible in comparison with the chemical energy, the Chapman-Jouguet detonation jump conditions apply at the front except near the axis and near the outer wall. The chemical heating in the detonation process increases the pressure and the temperature but considerably reduces the density near the front.

  4. Brane-induced-gravity shock waves.

    PubMed

    Kaloper, Nemanja

    2005-05-13

    We construct exact gravitational field solutions for a relativistic particle localized on a tensional brane in brane-induced gravity. They are a generalization of gravitational shock waves in 4D de Sitter space. We provide the metrics for both the normal branch and the self-inflating branch Dvali-Gabadadze-Porrati brane worlds, and compare them to the 4D Einstein gravity solution and to the case when gravity resides only in the 5D bulk, without any brane-localized curvature terms. At short distances the wave profile looks the same as in four dimensions. The corrections appear only far from the source, where they differ from the long distance corrections in 4D de Sitter space. We also discover a new nonperturbative channel for energy emission into the bulk from the self-inflating [corrected] branch, when gravity is modified at the de Sitter radius.

  5. Augmented Shock Wave Severance of Materials

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Schimmel, Morry L.

    1995-01-01

    This paper describes a new approach for severing or weakening a variety of materials. The technique employs embedding explosive cords into parallel grooves that are cut into a surface of a material. The cords are initiated simultaneously to produce shock waves that progress toward the centerline between the cords and the lower surface of the material. Intersecting incident and reflected waves augment at the centerline to fail or weaken the material in tension. No harmful debris is produced on the opposite side of the material from the explosive cords. The primary focus of the effort described in this paper was to fracture the F-16 aircraft trilaminate canopy. Also, complete severance was achieved in 2024-T4 aluminum plate stock. Possible applications are through canopy egress and crew module severance from military aircraft and separation of rocket vehicle stages and payloads. This approach offers important advantages over explosive methods currently in use.

  6. Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

    DOEpatents

    Benjamin, R.F.

    1983-10-18

    An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

  7. Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

    DOEpatents

    Benjamin, R.F.

    1987-03-10

    An apparatus is disclosed for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously. 3 figs.

  8. Optical pin apparatus for measuring the arrival time and velocity of shock waves and particles

    DOEpatents

    Benjamin, Robert F.

    1987-01-01

    An apparatus for the detection of the arrival and for the determination of the velocity of disturbances such as shock-wave fronts and/or projectiles. Optical pins using fluid-filled microballoons as the light source and an optical fiber as a link to a photodetector have been used to investigate shock-waves and projectiles. A microballoon filled with a noble gas is affixed to one end of a fiber-optic cable, and the other end of the cable is attached to a high-speed streak camera. As the shock-front or projectile compresses the microballoon, the gas inside is heated and compressed producing a bright flash of light. The flash of light is transmitted via the optic cable to the streak camera where it is recorded. One image-converter streak camera is capable of recording information from more than 100 microballoon-cable combinations simultaneously.

  9. Electrohydrodynamic instability of ion-concentration shock wave in electrophoresis

    NASA Astrophysics Data System (ADS)

    Gaur, Rahul; Bahga, Supreet Singh

    2017-06-01

    Capillary electrophoresis techniques often involve ion-concentration shock waves in an electrolyte solution, propagating under the effect of an external electric field. These shock waves are characterized by self-sharpening gradients in ion concentrations and electrical conductivity that are collinear with the electric field. The coupling of electric field and fluid motion at the shock interface sometimes leads to an undesirable electrohydrodynamic (EHD) instability. Using linear stability analysis, we describe the motion of small-amplitude disturbances of an electrophoretic shock wave. Our analysis shows that the EHD instability results due to the competition between destabilizing electroviscous flow and stabilizing electromigration of the shock wave. The ratio of timescales corresponding to electroviscous flow and electromigration yields a threshold criterion for the onset of instability. We present a validation of this threshold criterion with published experimental data and also describe the physical mechanism underlying the EHD instability of the electrophoretic shock wave.

  10. Radial Shock Wave Devices Generate Cavitation

    PubMed Central

    Császár, Nikolaus B. M.; Angstman, Nicholas B.; Milz, Stefan; Sprecher, Christoph M.; Kobel, Philippe; Farhat, Mohamed; Furia, John P.; Schmitz, Christoph

    2015-01-01

    Background Conflicting reports in the literature have raised the question whether radial extracorporeal shock wave therapy (rESWT) devices and vibrating massage devices have similar energy signatures and, hence, cause similar bioeffects in treated tissues. Methods and Findings We used laser fiber optic probe hydrophone (FOPH) measurements, high-speed imaging and x-ray film analysis to compare fundamental elements of the energy signatures of two rESWT devices (Swiss DolorClast; Electro Medical Systems, Nyon, Switzerland; D-Actor 200; Storz Medical, Tägerwillen, Switzerland) and a vibrating massage device (Vibracare; G5/General Physiotherapy, Inc., Earth City, MO, USA). To assert potential bioeffects of these treatment modalities we investigated the influence of rESWT and vibrating massage devices on locomotion ability of Caenorhabditis elegans (C. elegans) worms. Results FOPH measurements demonstrated that both rESWT devices generated acoustic waves with comparable pressure and energy flux density. Furthermore, both rESWT devices generated cavitation as evidenced by high-speed imaging and caused mechanical damage on the surface of x-ray film. The vibrating massage device did not show any of these characteristics. Moreover, locomotion ability of C. elegans was statistically significantly impaired after exposure to radial extracorporeal shock waves but was unaffected after exposure of worms to the vibrating massage device. Conclusions The results of the present study indicate that both energy signature and bioeffects of rESWT devices are fundamentally different from those of vibrating massage devices. Clinical Relevance Prior ESWT studies have shown that tissues treated with sufficient quantities of acoustic sound waves undergo cavitation build-up, mechanotransduction, and ultimately, a biological alteration that “kick-starts” the healing response. Due to their different treatment indications and contra-indications rESWT devices cannot be equated to vibrating

  11. Particle Acceleration in SN1006 Shock Waves

    NASA Technical Reports Server (NTRS)

    Sonneborn, George (Technical Monitor); Raymond, John C.

    2004-01-01

    The FUSE data have been reduced, and a paper on the results is in progress. The main results have been presented in a poster at the January 2004 AAS meeting and an ApJ paper in press. The primary result is that the widths of the 0 VI lines in the NW filament are a bit less than the width expected if the oxygen kinetic temperature is 16 times the proton temperature (mass proportional heating). This is at variance with measurements of shocks in the heliosphere, where preferential heating of oxygen and other heavy species is observed. The paper discusses the theoretical implications for collisionless shock wave physics. A secondary result is that no O VI emission was observed from the NE filament. While the very different particle distribution in that region can partially account for the weakness of the O VI lines, the simplest interpretation is that the pre-shock density in the NE is less than 0.22 times the density in the NW.

  12. Experimental particle acceleration by water evaporation induced by shock waves

    NASA Astrophysics Data System (ADS)

    Scolamacchia, T.; Alatorre Ibarguengoitia, M.; Scheu, B.; Dingwell, D. B.; Cimarelli, C.

    2010-12-01

    condensation front exhibited large accelerations, with velocity varying from few tens of m/s up to 479 (±0.5) m/s, at distances of 1.5 (±0.3) cm and in times of 0.1 ms. This process preceded the appearance of the Ar front. Our first results suggest that the evaporation of moisture induced by compression waves associated with the air shock is able to accelerate particles (ca.100s microns in size) efficiently, at short distances. This process could have broader implications in active volcanic areas where shock waves are generated, for the damage that may follow.

  13. Shock-wave boundary layer interactions

    NASA Technical Reports Server (NTRS)

    Delery, J.; Marvin, J. G.; Reshotko, E.

    1986-01-01

    Presented is a comprehensive, up-to-date review of the shock-wave boundary-layer interaction problem. A detailed physical description of the phenomena for transonic and supersonic speed regimes is given based on experimental observations, correlations, and theoretical concepts. Approaches for solving the problem are then reviewed in depth. Specifically, these include: global methods developed to predict sudden changes in boundary-layer properties; integral or finite-difference methods developed to predict the continuous evolution of a boundary-layer encountering a pressure field induced by a shock wave; coupling methods to predict entire flow fields; analytical methods such as multi-deck techniques; and finite-difference methods for solving the time-dependent Reynolds-averaged Navier-Stokes equations used to predict the development of entire flow fields. Examples are presented to illustrate the status of the various methods and some discussion is devoted to delineating their advantages and shortcomings. Reference citations for the wide variety of subject material are provided for readers interested in further study.

  14. Smart structures for shock wave attenuation using ER inserts

    NASA Astrophysics Data System (ADS)

    Kim, Jaehwan; Kim, Jung-Yup; Choi, Seung-Bok; Kim, Kyung-Su

    2001-08-01

    This Paper demonstrates the possibility of shock wave attenuation propagating through a smart structure that incorporates ER insert. The wave transmission of ER inserted beam is theoretically derived using Mead & Markus model and the theoretical results are compared with the finite element analysis results. To experimentally verify the shock wave attenuation, ER insert in an aluminum plate is made and two piezoceramic disks are used as transmitter and receiver of the wave. The transmitter sends a sine pulse signal such that a component of shock wave travels through the plate structure and the receiver gets the transmitted wave signal. Wave propagation of the ER insert can be adjusted by changing the applied electric field on the ER insert. Details of the experiment are addressed and the possibility of shock wave attenuation is experimentally verified. This kind of smart structure can be used for warship and submarine hull structures to protect fragile and important equipment.

  15. Evolution of electric response of Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 and Pb0.99[(Zr0.90Sn0.10)0.96Ti0.04]0.98Nb0.02O3 ferroelectric ceramics under shock wave compression

    NASA Astrophysics Data System (ADS)

    Jiang, Dongdong; Du, Jinmei; Gu, Yan; Feng, Yujun

    2012-06-01

    The objective of this work is to investigate the dependence of the electric behavior on shock pressure in Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 (PZT 95/5-2Nb) and Pb0.99[(Zr0.90Sn0.10)0.96Ti0.04]0.98Nb0.02O3 (PZST) ferroelectric ceramics under shock wave compression. PZT 95/5-2Nb and PZST ceramics were subjected to high dynamic pressure generated by plate impacts. The output currents were measured under the short-circuit condition in the pressure range from 0.23 to 4.50 GPa. The evolution of the electric response exhibits three distinct regions: (1) Below the critical phase transition pressure (σC), alternate negative and positive piezoelectric currents are observed and the corresponding piezoelectric constant is e 31. (2) Above σC and below the complete phase transition pressure (σH), released charge increases with increasing shock pressure, illustrating the transition of ferroelectric to antiferroelectric phase. (3) Above σH, the output current is insensitive to the shock pressure. A similar evolutionary process is also observed in hydrostatic and uniaxial stress experiments.

  16. Spatiotemporal dynamics of underwater conical shock wave focusing

    NASA Astrophysics Data System (ADS)

    Hoffer, P.; Lukes, P.; Akiyama, H.; Hosseini, H.

    2016-12-01

    The paper presents an experimental study on spatiotemporal dynamics of conical shock waves focusing in water. A multichannel pulsed electrohydraulic discharge source with a cylindrical ceramic-coated electrode was used. Time-resolved visualizations revealed that cylindrical pressure waves were focused to produce conical shock wave reflection over the axis of symmetry in water. Positive and negative pressures of 372 MPa and -17 MPa at the focus with 0.48 mm lateral and 22 mm axial extension (-6 dB) were measured by a fiber-optic probe hydrophone. The results clearly show the propagation process leading to the high-intensity underwater shock wave. Such strong and sharp shock wave focusing offers better localization for extracorporeal lithotripsy or other non-invasive medical shock wave procedures.

  17. Spatiotemporal dynamics of underwater conical shock wave focusing

    NASA Astrophysics Data System (ADS)

    Hoffer, P.; Lukes, P.; Akiyama, H.; Hosseini, H.

    2017-07-01

    The paper presents an experimental study on spatiotemporal dynamics of conical shock waves focusing in water. A multichannel pulsed electrohydraulic discharge source with a cylindrical ceramic-coated electrode was used. Time-resolved visualizations revealed that cylindrical pressure waves were focused to produce conical shock wave reflection over the axis of symmetry in water. Positive and negative pressures of 372 MPa and -17 MPa at the focus with 0.48 mm lateral and 22 mm axial extension (-6 dB) were measured by a fiber-optic probe hydrophone. The results clearly show the propagation process leading to the high-intensity underwater shock wave. Such strong and sharp shock wave focusing offers better localization for extracorporeal lithotripsy or other non-invasive medical shock wave procedures.

  18. Shock waves in a long-period optical fiber

    NASA Astrophysics Data System (ADS)

    Adamova, M. S.; Zolotovskiĭ, I. O.; Sementsov, D. I.

    2008-12-01

    The possibility of forming a shock wave of the pulse envelope has been investigated in a long-period or Bragg optical fiber with a system of two unidirectional linearly coupled waves. It has been demonstrated that, in principle, the possibility exists of forming a shock wave in a nonlinear optical fiber not only at the trailing edge but also at the leading edge of the wave packet. The origin of the formation of a shock wave depends substantially on the initial conditions providing excitation of the optical fiber.

  19. Waves in low-beta plasmas - Slow shocks

    NASA Technical Reports Server (NTRS)

    Steinolfson, R. S.; Hundhausen, A. J.

    1989-01-01

    Results from wave theory and numerical simulation of the nonlinear MHD equations are used to study the response of a conducting fluid containing an embedded magnetic field with beta less than 1 to the sudden injection of material along the field lines. It is shown that the injection produces slow shocks with configurations which are concave toward the ejecta driver. Fast-mode waves which have not steepened into the shock precede the slow shock and alter the ambient medium. When beta equals 0.1, the fast mode becomes a transverse wave for parallel propagation, while the slow wave approaches a longitudinal, or sound, wave.

  20. Shock wave propagation in semi-crystalline polyethylene: An atomic-scale investigation

    NASA Astrophysics Data System (ADS)

    Elder, Robert M.; O'Connor, Thomas C.; Yeh, In-Chul; Chantawansri, Tanya L.; Sirk, Timothy W.; Robbins, Mark O.; Andzelm, Jan W.

    Highly oriented polyethylene (PE) fibers are used in protection applications, therefore elucidation of their response under high strain-rate impact events is vital. Although PE fibers can have high crystallinity (>95%), they also contain defects such as amorphous domains. Using molecular dynamics simulations, we investigate shock propagation through crystalline, amorphous, and semi-crystalline PE. We generate compressive shock waves of varying strength, quantify their dynamics, and characterize their effect on material properties at the atomic scale. In the semi-crystalline PE model, the differing density and molecular order of amorphous PE and crystalline PE result in differing shock impedances, which causes reflection and refraction of shock waves at interfaces between the phases. We quantify the properties (e.g. pressure, velocity) of the reflected and refracted waves, which differ from those of the incident wave, and compare with results from impedance matching. We also examine the reflection, absorption, and transmission of energy at the crystalline-amorphous interface. Depending on shock strength, amorphous defects can dissipate shock energy, which attenuates the shock and leads to effects such as localized heating.

  1. One-Dimensional Shock Wave Formation by an Accelerating Piston. Ph.D. Thesis - Ohio State Univ.

    NASA Technical Reports Server (NTRS)

    Mann, M. J.

    1970-01-01

    The formation of a shock wave by a solid accelerating piston was studied. A theoretical solution using the method of characteristics for a perfect gas showed that a complex wave system exists, and that the compressed gas can have large gradients in temperature, density and entropy. Experiments were performed with a piston tube where piston speed, shock speed and pressure were measured. The comparison of theory and experiment was good.

  2. Response of magnesium single crystals to shock-wave loading at normal and elevated temperatures

    NASA Astrophysics Data System (ADS)

    Garkushin, G.; Kanel, G.; Savinykh, A.; Razorenov, S.; Jones, D.; Proud, W.

    2013-06-01

    Magnesium single crystals, 0.2 mm to 3 mm thick, were shock loaded along the two axes, a, c and the direction at 45 degrees to the c-axis. At the room temperature the response is very similar to that observed by Pope and Johnson for beryllium single crystals (1974). Shock compression along the c-axis causes inelastic deformation by means of pyramidal slip and twinning and is associated with the largest HEL. The easiest basal slip was activated by shock loading along the inclined, off-axis direction and is associated with smallest HEL value. For all orientations, we observed elastic precursor decay and growth of the HEL values with increasing temperature. However, for the c-orientation the growth is caused by decrease of elastic constants and not with an increase of resolved shear stress along the pyramidal slip planes. In the other orientations the resolved shear stresses in slip planes at the HEL increased with temperature. At inclined shock compression we found two plastic shock waves for which the stress behind the first depends on the peak stress associated with the second plastic wave. The crystals demonstrate the largest spall strength at shock loading along the a-axis and smallest one at shock loading in off-axis direction.

  3. The History of the APS Shock Compression of Condensed Matter Topical Group

    NASA Astrophysics Data System (ADS)

    Forbes, Jerry W.

    2001-06-01

    To provide broader scientific recognition and to advance the science of shock-compressed condensed matter, a group of APS members worked within the Society to make this technical field an active part of APS. Individual papers were given at APS meetings starting in the 1950’s and then later whole sessions were organized starting at the 1967 Pasadena meeting. Topical conferences began in 1979 in Pullman, WA where George Duvall and Dennis Hayes were co-chairs. Most all early topical conferences were sanctioned by the APS while those held after 1985 were official APS meetings. In 1984, after consulting with a number of people in the shock wave field, Robert Graham circulated a petition to form an APS topical group. He obtained signatures from a balanced cross-section of the community. William Havens, the executive secretary of APS, informed Robert Graham by letter on November 28, 1984 that the APS Council had officially accepted the formation of this topical group at its October 28, 1984 meeting. The first election occurred July 23, 1985 where Robert Graham was elected chairman, William Nellis vice-chairman, and Jerry Forbes secretary/treasurer. The topical group remains viable today by holding a topical conference in odd numbered years and shock wave sessions at APS general meetings in even numbered years A major benefit of being an official unit of APS is the allotment of APS fellows every year. The APS shock compression award established in 1987, has also provided broad recognition of many major scientific accomplishments in this field.

  4. Interaction of weak shock waves and discrete gas inhomogeneities

    NASA Astrophysics Data System (ADS)

    Haas, Jean-Francois Luc

    An experimental investigation of the interaction of shock waves with discrete gas inhomogeneities is conducted in the GALCIT 15 cm diameter shock tube. The gas volumes are cylindrical refraction cells of 5 cm diameter with a 0.5 [...] thick membrane separating the test gas (helium or Freon 22) from the ambient air and large spherical soap bubbles containing the same gases. The incident wave Mach numbers are nominally 1.09 and 1.22. The wave pattern and the deformation of the gas volumes are documented by shadowgraphs. The transmitted and diffracted wave pressure profiles are recorded by pressure transducers at various distances behind the cylinders. The basic phenomena of acoustic wave refraction, reflection and diffraction by cylindrical acoustic lenses, with indices of refraction appropriate to the gases used in the experiments, are illustrated with computer-generated ray and wave-front diagrams. In the case of a Freon 22-filled cylinder, the wave diffracted externally around the body precedes the wave transmitted from the interior which goes through a focus just behind the cylinder, while in the case of the helium-filled cylinder the expanding transmitted wave runs ahead of the diffracted wave. Both sets of waves merge a few cylinder diameters downstream. The wave patterns inside the cylinder, showing initially the refracted waves and later the same waves reflected internally, present some interesting phenomena. The mechanisms by which the gas volumes are transformed into vertical structures by the shock motion are observed. The unique effect of shock acceleration and Rayleigh-Taylor instability on the spherical volume of helium leads to the formation of a strong vortex ring which rapidly separates from the main volume of helium. Measurements of the wave and gas-interface velocities are compared to values calculated for one-dimensional interactions and for a simple model of shock-induced Taylor instability. The behavior of thin liquid membranes accelerated by

  5. Analytical solution of the problem of a shock wave in the collapsing gas in Lagrangian coordinates

    NASA Astrophysics Data System (ADS)

    Kuropatenko, V. F.; Shestakovskaya, E. S.

    2016-10-01

    It is proposed the exact solution of the problem of a convergent shock wave and gas dynamic compression in a spherical vessel with an impermeable wall in Lagrangian coordinates. At the initial time the speed of cold ideal gas is equal to zero, and a negative velocity is set on boundary of the sphere. When t > t0 the shock wave spreads from this point into the gas. The boundary of the sphere will move under the certain law correlated with the motion of the shock wave. The trajectories of the gas particles in Lagrangian coordinates are straight lines. The equations determining the structure of the gas flow between the shock front and gas border have been found as a function of time and Lagrangian coordinate. The dependence of the entropy on the velocity of the shock wave has been found too. For Lagrangian coordinates the problem is first solved. It is fundamentally different from previously known formulations of the problem of the self-convergence of the self-similar shock wave to the center of symmetry and its reflection from the center, which was built up for the infinite area in Euler coordinates.

  6. Electrical Properties of PZT 52/48 under Ramp Wave Compression

    NASA Astrophysics Data System (ADS)

    Jackson, D. P.; Montgomery, S. T.; Wise, J. L.; Clark, G. E.; Duckett, E. B.

    2011-06-01

    Measurements of electrical responses from ferroelectric ceramic disks under shock wave compression where the directions of wave propagation and remanent polarization are aligned have been conducted on a variety of lead zirconate titanate compositions. Analysis of the electrical responses is complicated by the electric conditions in the disk, tilt in the planar shock, and the variety of material compositions examined. A review of previous measurements on PZT 65/35 ceramic, at stress levels not expected to drive the material into the paraelectric phase and where charge is restricted from flowing from the disk, indicates that above a certain stress threshold the available charge release is complete and the inverse permittivity in the shock compressed ceramic increases linearly with compressive stress. An electrical response model, based on the these observations, is used to explain the electric output from experiments on PZT 52/48 disks under ramp wave compression when the disk faces are connected through a small, or very large, resistive load. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  7. Generation of Pc 1 waves by the ion temperature anisotropy associated with fast shocks caused by sudden impulses

    NASA Technical Reports Server (NTRS)

    Mandt, M. E.; Lee, L. C.

    1991-01-01

    The high correlation of Pc 1 events with magnetospheric compressions is known. A mechanism is proposed which leads to the generation of Pc 1 waves. The interaction of a dynamic pressure pulse with the earth's bow shock leads to the formation of a weak fast-mode shock propagating into the magnetoshealth. The shock wave can pass right through a tangential discontinuity (magnetopause) and into the magnetosphere, without disturbing either of the structures. In a quasiperpendicular geometry, the shock wave exhibits anisotropic heating. This anisotropy drives unstable ion-cyclotron waves which can contribute to the generation of the Pc 1 waves which are detected. The viability of the mechanism is demonstrated with simulations. This mechanism could explain the peak in the occurrence of observed Pc 1 waves in the postnoon sector where a field-aligned discontinuity in the solar wind would most often be parallel to the magnetopause surface due to the average Parker-spiral magnetic-field configuration.

  8. Steady state risetimes of shock waves in the atmosphere

    NASA Technical Reports Server (NTRS)

    Raspet, Richard; Bass, Henry; Yao, Lixin; Wu, Wenliang

    1992-01-01

    A square wave shape is used in the Pestorius algorithm to calculate the risetime of a step shock in the atmosphere. These results agree closely with steady shock calculations. The healing distance of perturbed shocks due to finite wave effects is then investigated for quasi-steady shocks. Perturbed 100 Pa shocks require on the order of 1.0 km travel distance to return to within 10 percent of their steady shock risetime. For 30 Pa shocks, the minimum recovery distance increases to 3.0 km. It is unlikely that finite wave effects can remove the longer risetimes and irregular features introduced into the sonic boom by turbulent scattering in the planetary boundary layer.

  9. Interplanetary shock waves and the structure of solar wind disturbances

    NASA Technical Reports Server (NTRS)

    Hundhausen, A. J.

    1972-01-01

    Observations and theoretical models of interplanetary shock waves are reviewed, with emphasis on the large-scale characteristics of the associated solar wind disturbances and on the relationship of these disturbances to solar activity. The sum of observational knowledge indicates that shock waves propagate through the solar wind along a broad, roughly spherical front, ahead of plasma and magnetic field ejected from solar flares. Typically, the shock front reaches 1 AU about two days after its flare origin, and is of intermediate strength. Not all large flares produce observable interplanetary shock waves; the best indicator of shock production appears to be the generation of both type 2 and type 4 radio bursts by a flare. Theoretical models of shock propagation in the solar wind can account for the typically observed shock strength, transit time, and shape.

  10. Laser measurements of bacterial endospore destruction from shock waves

    NASA Astrophysics Data System (ADS)

    Lappas, Petros P.; McCartt, A. Daniel; Gates, Sean D.; Jeffries, Jay B.; Hanson, Ronald K.

    2013-12-01

    The effects of shock waves on bioaerosols containing endospores were measured by combined laser absorption and scattering. Experiments were conducted in the Stanford aerosol shock tube for post-shock temperatures ranging from 400 K to 1100 K. Laser intensity measurements through the test section of the shock tube at wavelengths of 266 and 665 nm provided real-time monitoring of the morphological changes (includes changes in shape, structure and optical properties) in the endospores. Scatter of the visible light measured the integrity of endospore structure, while absorption of the UV light provided a measure of biochemicals released when endospores ruptured. For post-shock temperatures above 750 K the structural breakdown of Bacillus atrophaeus (BA) endospores was observed. A simple theoretical model using laser extinction is presented for determining the fraction of endospores that are ruptured by the shock waves. In addition, mechanisms of endospore mortality preceding their disintegration due to shock waves are discussed.

  11. MD simulation of steady shock-wave fronts with phase transition in single-crystal iron

    NASA Astrophysics Data System (ADS)

    Zhakhovsky, V. V.; Migdal, K. P.; Inogamov, N. A.; Anisimov, S. I.

    2017-01-01

    Overdriven shock waves propagating in main crystallographic directions of single-crystal bcc iron were studied with moving-window molecular dynamics (MD) technique. To simulate correctly the shock-induced bcc-to-hcp phase transition in iron a new EAM potential fitted to the cold pressure curves and pressure transition at 13 GPa was developed with the stress matching method. We demonstrate that structure of shock fronts depends on orientation of crystal. A peculiar structure of steady shock-wave front in [100] direction is observed. While the ultra-fast α → ɛ transition initiated in uniaxially compressed crystal along [100] in elastic zone transforms bcc completely to hcp phase, transformation in other directions is performed only partially with production of metastable composition of nanometer-sized bcc-hcp-fcc grains.

  12. Shock compression experiment of forsterite: pulverization and frictional melting in a shear regime

    NASA Astrophysics Data System (ADS)

    Obata, M.; Mashimo, T.; Ando, J. I.; Chen, L.; Yamamoto, T.

    2015-12-01

    Seismic waves may be generated by a rapid slip accompanied by a rapid stress drop at or near the running rapture tip. To study the detailed processes and the material change occurring at the fracture tip, we performed a series of shock compression experiments using a keyed powder gun and a single crystal of forsterite Fo 94. A olivine disket (diameter 12 mm, thickness 3 mm, perpendicular to the c-axis) is mounted in a steel capsule of diameter 2 cm and length 4 cm. Flyer speed was 1.5 km/s; applied pressure was ca. 31 GPa; and shock wave velocity and particle velocity were ca. 7 km/s and ca. 1 km/s, respectively. After the shock experiment the sample was recovered and examined by optical microscopy, SEM and TEM. Although the olivine largely remained to be a single crystal, it shows wavy extinctions and many parallel shear planes diagonal to the compression axis. Shear planes (i.e., fault) are macroscopically sharp and show displacement of up to 0.5 mm. The TEM observation of the fault wall revealed that the wall has a zonal structure. Well inside the wall are developed densely spaced and tangles [001] screw dislocations. Outer 2-5 micron zone is polycrystalline olivine of grain size 200-300 nm. The outermost zone is an aggregate of semi-rounded small olivine particles (ca. 200 nanometers) mounted in a matrix of glass of olivine composition. It is inferred from these microstructures that polygonization and pulverization predated the melting. Such pulverization is possible at a running fracture tip, where stress and strain rate are the highest. Moreover, very thin injection veins (ca. 50-350 nanometer thick) filled with olivine glasses locally occurred in the fault wall, suggesting fracturing and crack opening had occurred while olivine melt was present. The fracturing was probably propelled by the rapid sweep of shock waves running through the crystal. Melting probably took place by a rapid collision and frictions among the olivine nanoparticles. It is suggested

  13. Shock Waves for Possible Application in Regenerative Medicine

    NASA Astrophysics Data System (ADS)

    Hosseini, S. H. R.; Nejad, S. Moosavi; Akiyama, H.

    The paper reports experimental study of underwater shock waves effects in modification and possible control of embryonic stem cell differentiation and proliferation. The study is motivated by its application in regenerativemedicine. Underwater shock waves have been of interest for various scientific, industrial, and medical applications.

  14. Temperature maxima in stable two-dimensional shock waves

    NASA Astrophysics Data System (ADS)

    Kum, Oyeon; Hoover, Wm. G.; Hoover, C. G.

    1997-07-01

    We use molecular dynamics to study the structure of moderately strong shock waves in dense two-dimensional fluids, using Lucy's pair potential. The stationary profiles show relatively broad temperature maxima, for both the longitudinal and the average kinetic temperatures, just as does Mott-Smith's model for strong shock waves in dilute three-dimensional gases.

  15. Tandem shock wave cavitation enhancement for extracorporeal lithotripsy

    NASA Astrophysics Data System (ADS)

    Loske, Achim M.; Prieto, Fernando E.; Fernández, Francisco; van Cauwelaert, Javier

    2002-11-01

    Extracorporeal shock wave lithotripsy (ESWL) has been successful for more than twenty years in treating patients with kidney stones. Hundreds of underwater shock waves are generated outside the patient's body and focused on the kidney stone. Stones fracture mainly due to spalling, cavitation and layer separation. Cavitation bubbles are produced in the vicinity of the stone by the tensile phase of each shock wave. Bubbles expand, stabilize and finally collapse violently, creating stone-damaging secondary shock waves and microjets. Bubble collapse can be intensified by sending a second shock wave a few hundred microseconds after the first. A novel method of generating two piezoelectrically generated shock waves with an adjustable time delay between 50 and 950 µs is described and tested. The objective is to enhance cavitation-induced damage to kidney stones during ESWL in order to reduce treatment time. In vitro kidney stone model fragmentation efficiency and pressure measurements were compared with those for a standard ESWL system. Results indicate that fragmentation efficiency was significantly enhanced at a shock wave delay of about 400 and 250 µs using rectangular and spherical stone phantoms, respectively. The system presented here could be installed in clinical devices at relatively low cost, without the need for a second shock wave generator.

  16. The mechanism of shock wave treatment in bone healing

    NASA Astrophysics Data System (ADS)

    Wang, Ching-Jen

    2005-04-01

    The purpose of this study was to investigate the biological mechanism of shock wave treatment in bone healing in rabbits. A closed fracture of the right femur was created with a three-point bend method and the fracture was stabilized with an intra-medullary pin. Shock waves were applied one week after the fracture. Twenty-four New Zealand white rabbits were randomly divided into 3 groups. Group 1 (the control) received no shock waves; group 2 received low-energy and group 3 high-energy shock waves. The animals were sacrificed at 24 weeks, and a 5-cm segment of the femur bone including the callus was harvested. The specimens were studied with histomorphological examination, biomechanical analysis and immunohistochemical stains. The results showed that high-energy shock waves improved bone healing with significant increases in cortical bone formation and the number neovascularization in histomorphology, better bone strength and bone mass in biomechanics, and increased expressions of angiogenic growth markers including BMP-2, eNOS, VEGF and PCNA than the control and low-energy shock wave groups. The effect of shock wave treatment appears to be dose-dependent. In conclusion, high-energy shock waves promote bone healing associated with ingrowth of neovascularization and increased expressions of angiogenic growth factors.

  17. Interaction of Isotropic Turbulence with a Shock Wave

    DTIC Science & Technology

    1992-03-01

    5 1.3 Objectives and Overview....................................... 6 2. Linear Analysis...Length Scales .................................. 74 4.1.5 Thermodynamic Properties ................................ 75 5 4.1.6 M odeling Issues...78 4.2 Modification of a Shock Wave ...................................... 82 5 4.2.1 Statistics of a Shock Wave

  18. Numerical simulation of shock wave emanating from a square shock tube

    NASA Astrophysics Data System (ADS)

    Abe, Akihisa; Itoh, Katsuhiro; Takayama, Kazuyoshi

    1990-11-01

    The flow field behind a shock wave emitted from a square shock tube was studied. Being 3-D, various phenomena were observed for axisymmetric flow such as distorted vortex ring structures generated from the shock tube exit, shock wave deformation, and a variety of flow structures behind the shock wave. If the generative mechanisms of distorted vortex ring and flows from the shock tube are clear, this also contributes to the technical advancement, regarding the mixture of different chemical species. The shock wave emanating from a square shock tube was studied in numerical simulation and shock tube experiment. In order to simulate these flow fields, a second order upwind Total Variation Diminishing (TVD) finite difference scheme was used. The TVD scheme, having been used for 2-D problems, was extended to 3-D and applied to Euler equations. The computational domain of 60 x 60 x 60 grid points covers a quarter of the shock tube cross section. As an initial configuration, a normal shock wave with Mach 1.5 was taken. The numerical results were compared with data from optical measurements. Good qualitative agreement was obtained between numerical and experimental results.

  19. A numerical scheme for ionizing shock waves

    SciTech Connect

    Aslan, Necdet . E-mail: naslan@yeditepe.edu.tr; Mond, Michael

    2005-12-10

    A two-dimensional (2D) visual computer code to solve the steady state (SS) or transient shock problems including partially ionizing plasma is presented. Since the flows considered are hypersonic and the resulting temperatures are high, the plasma is partially ionized. Hence the plasma constituents are electrons, ions and neutral atoms. It is assumed that all the above species are in thermal equilibrium, namely, that they all have the same temperature. The ionization degree is calculated from Saha equation as a function of electron density and pressure by means of a nonlinear Newton type root finding algorithms. The code utilizes a wave model and numerical fluctuation distribution (FD) scheme that runs on structured or unstructured triangular meshes. This scheme is based on evaluating the mesh averaged fluctuations arising from a number of waves and distributing them to the nodes of these meshes in an upwind manner. The physical properties (directions, strengths, etc.) of these wave patterns are obtained by a new wave model: ION-A developed from the eigen-system of the flux Jacobian matrices. Since the equation of state (EOS) which is used to close up the conservation laws includes electronic effects, it is a nonlinear function and it must be inverted by iterations to determine the ionization degree as a function of density and temperature. For the time advancement, the scheme utilizes a multi-stage Runge-Kutta (RK) algorithm with time steps carefully evaluated from the maximum possible propagation speed in the solution domain. The code runs interactively with the user and allows to create different meshes to use different initial and boundary conditions and to see changes of desired physical quantities in the form of color and vector graphics. The details of the visual properties of the code has been published before (see [N. Aslan, A visual fluctuation splitting scheme for magneto-hydrodynamics with a new sonic fix and Euler limit, J. Comput. Phys. 197 (2004) 1

  20. IPShocks: Database of Interplanetary Shock Waves

    NASA Astrophysics Data System (ADS)

    Isavnin, Alexey; Lumme, Erkka; Kilpua, Emilia; Lotti, Mikko; Andreeova, Katerina; Koskinen, Hannu; Nikbakhsh, Shabnam

    2016-04-01

    Fast collisionless shocks are one of the key interplanetary structures, which have also paramount role for solar-terrestrial physics. In particular, coronal mass ejection driven shocks accelerate particles to high energies and turbulent post-shock flows may drive intense geomagnetic storms. We present comprehensive Heliospheric Shock Database (ipshocks.fi) developed and hosted at University of Helsinki. The database contains currently over 2000 fast forward and fast reverse shocks observed by Wind, ACE, STEREO, Helios, Ulysses and Cluster spacecraft. In addition, the database has search and sort tools based on the spacecraft, time range, and several key shock parameters (e.g., shock type, shock strength, shock angle), data plots for each shock and data download options. These features allow easy access to shocks and quick statistical analyses. All current shocks are identified visually and analysed using the same procedure.

  1. Formation of Chondrules by Shock Waves

    NASA Astrophysics Data System (ADS)

    Morris, M. A.; Boley, A. C.

    2017-02-01

    We describe and assess current shock models for chondrule formation, particularly those driven by gravitational disk instabilities and bow shocks. We discuss predictions made by shock models and further work needed.

  2. Radiant properties of strong shock waves in argon.

    PubMed

    Taylor, W H; Kane, J W

    1967-09-01

    Measurements of the visible radiation emitted by one dimensional, explosively generated, shock waves in argon initially at 1 atm are reported. A time-resolved spectrograph and calibrated photodetectors were used to measure the intensity of the source at 5450 A and 4050 A. The results show that explosive induced shock waves in argon having shock velocities in the range 8-9 mm/microusec radiate at these wavelengths like a blackbody having a temperature of approximately 23,000 degrees K.

  3. Biomechanical and Biochemical Cellular Response Due to Shock Waves

    DTIC Science & Technology

    2008-12-01

    using shock- wave-induced cavitation . Ultrasound in Medicine and Biology, 29, 1769-1776. Lew, H. L., J. H. Poole, S. Alvarez, and W. Moore, 2005...sheets of adipose derived stem cells to shock waves. A key guideline in the experimental design was to suppress cavitation . To this end we...shock-exposed cells and controls. We attribute this to the absence of cavitation . Time-resolved gene expression revealed that a large

  4. Shock compression measurements at 1 to 7 TPa

    NASA Astrophysics Data System (ADS)

    Ragan, Charles E., III

    1982-06-01

    A shock wave generated by an underground nuclear explosion was used to perform impedance-matching experiments for several different materials at pressures from 1 to 7 TPa. The nearly planar shock passed through a 180-mm-diam by 12-mm-thick molybdenum standard and into stacks of 10-mm-thick samples of the following adjacent pairs of materials: LiD-Be, Be-LiD, Al-Mo, Pb-quartz, W-Mo (low density, ρ0=8.29 g cm-3), U-Mo, and Fe. An array of 75 electrical contact pins was used to determine the shape of the shock front and the shock velocities in the standard and in the samples with uncertainties ranging from 1.5 to 2.5%. The measured shock velocity of 27.30 km/s (+/-1.5%) in the molybdenum standard corresponds to a pressure of 4.95 TPa (+/-3.5%) based on a theoretical equation of state (EOS) that includes electronic-shell-structure effects. An impedance-matching analysis was performed for each sample stack to obtain Hugoniot data for all samples except those in the U-Mo stack; neutron-induced fission heating in the uranium perturbed the initial state and produced inconclusive results. Predictions, based on the SESAME EOS library, of shock velocities in most samples agree with the experimental results within the uncertainties. For the quartz and low-density molybdenum, the SESAME-predicted shock velocities are too large by 5 to 10%. The following Hugoniot points in pressure (P)-particle-velocity (u) coordinates were determined for the indicated samples: LiD (p=0.946 TPa, u=29.39 km/s), Be (1.46, 22.69); Be (1.79, 25.42), LiD (1.038, 31.23); Al (2.23, 23.89), Mo (4.03, 16.05); Pb (4.80, 17.84), quartz (1.66, 23.64); W (6.51, 15.10), and Mo (ρ0=8.29 g cm-3) (3.68, 18.27). The results for iron have a larger uncertainty but are consistent with the SESAME predictions.

  5. Dispersive shock waves in nematic liquid crystals

    NASA Astrophysics Data System (ADS)

    Smyth, Noel F.

    2016-10-01

    The propagation of coherent light with an initial step intensity profile in a nematic liquid crystal is studied using modulation theory. The propagation of light in a nematic liquid crystal is governed by a coupled system consisting of a nonlinear Schrödinger equation for the light beam and an elliptic equation for the medium response. In general, the intensity step breaks up into a dispersive shock wave, or undular bore, and an expansion fan. In the experimental parameter regime for which the nematic response is highly nonlocal, this nematic bore is found to differ substantially from the standard defocusing nonlinear Schrödinger equation structure due to the effect of the nonlocality of the nematic medium. It is found that the undular bore is of Korteweg-de Vries equation-type, consisting of bright waves, rather than of nonlinear Schrödinger equation-type, consisting of dark waves. In addition, ahead of this Korteweg-de Vries bore there can be a uniform wavetrain with a short front which brings the solution down to the initial level ahead. It is found that this uniform wavetrain does not exist if the initial jump is below a critical value. Analytical solutions for the various parts of the nematic bore are found, with emphasis on the role of the nonlocality of the nematic medium in shaping this structure. Excellent agreement between full numerical solutions of the governing nematicon equations and these analytical solutions is found.

  6. Photoacoustic shock wave emission and cavitation from structured optical fiber tips

    NASA Astrophysics Data System (ADS)

    Mohammadzadeh, Milad; Gonzalez Avila, Silvestre Roberto; Wan, Yin Chi; Wang, Xincai; Zheng, Hongyu; Ohl, Claus-Dieter

    2015-11-01

    Fiber optics are used in medicine to deliver laser pulses for microsurgery. Upon absorption of a high-power laser pulse, a thermoelastic wave is emitted from the fiber tip. If a flat cleaved fiber is used, the photoacoustic field comprises a planar compressive shock wave and a tensile diffraction wave from the tip edge. Here we demonstrate that by modifying the geometry of a fiber tip, multiple shock waves can be generated from a single laser pulse. Flat cleaved fibers generate tension only along the fiber axis and with one compression-tension cycle from a laser pulse; however, structured fiber tips cause significant tension both along and off-axis, and generate multiple pressure cycles from a single laser pulse. Fast flash photography reveals that diffraction waves from the edges of the tip structures overlap and generate enough tension to form cavitation clouds. We numerically solve the linear wave equation to model the acoustic transients of structured fiber tips and achieve good agreement with pressure measurements from a fiber optic hydrophone. Multiple shock wave emission from a single laser pulse introduces structured fiber tips as a candidate to deliver histotripsy effects via a surgical catheter for micro-scale ablation of soft tissue.

  7. Shock Compression of Metal Crystals: A Comparison of Eulerian and Lagrangian Elastic-Plastic Theories

    DTIC Science & Technology

    2014-11-01

    Shock Compression of Metal Crystals: A Comparison of Eulerian and Lagrangian Elastic- Plastic Theories by JD Clayton ARL-RP-0513...of Metal Crystals: A Comparison of Eulerian and Lagrangian Elastic- Plastic Theories JD Clayton Weapons and Materials Research Directorate, ARL...SUBTITLE Shock Compression of Metal Crystals: A Comparison of Eulerian and Lagrangian Elastic- Plastic Theories 5a. CONTRACT NUMBER 5b. GRANT

  8. Schlieren imaging of loud sounds and weak shock waves in air near the limit of visibility

    NASA Astrophysics Data System (ADS)

    Hargather, Michael John; Settles, Gary S.; Madalis, Matthew J.

    2010-02-01

    A large schlieren system with exceptional sensitivity and a high-speed digital camera are used to visualize loud sounds and a variety of common phenomena that produce weak shock waves in the atmosphere. Frame rates varied from 10,000 to 30,000 frames/s with microsecond frame exposures. Sound waves become visible to this instrumentation at frequencies above 10 kHz and sound pressure levels in the 110 dB (6.3 Pa) range and above. The density gradient produced by a weak shock wave is examined and found to depend upon the profile and thickness of the shock as well as the density difference across it. Schlieren visualizations of weak shock waves from common phenomena include loud trumpet notes, various impact phenomena that compress a bubble of air, bursting a toy balloon, popping a champagne cork, snapping a wooden stick, and snapping a wet towel. The balloon burst, snapping a ruler on a table, and snapping the towel and a leather belt all produced readily visible shock-wave phenomena. In contrast, clapping the hands, snapping the stick, and the champagne cork all produced wave trains that were near the weak limit of visibility. Overall, with sensitive optics and a modern high-speed camera, many nonlinear acoustic phenomena in the air can be observed and studied.

  9. Optical observation of shock waves and cavitation bubbles in high intensity laser-induced shock processes

    SciTech Connect

    Marti-Lopez, L.; Ocana, R.; Porro, J. A.; Morales, M.; Ocana, J. L.

    2009-07-01

    We report an experimental study of the temporal and spatial dynamics of shock waves, cavitation bubbles, and sound waves generated in water during laser shock processing by single Nd:YAG laser pulses of nanosecond duration. A fast ICCD camera (2 ns gate time) was employed to record false schlieren photographs, schlieren photographs, and Mach-Zehnder interferograms of the zone surrounding the laser spot site on the target, an aluminum alloy sample. We recorded hemispherical shock fronts, cylindrical shock fronts, plane shock fronts, cavitation bubbles, and phase disturbance tracks.

  10. Plasma Shock Wave Modification Experiments in a Temperature Compensated Shock Tube

    NASA Technical Reports Server (NTRS)

    Vine, Frances J.; Mankowski, John J.; Saeks, Richard E.; Chow, Alan S.

    2003-01-01

    A number of researchers have observed that the intensity of a shock wave is reduced when it passes through a weakly ionized plasma. While there is little doubt that the intensity of a shock is reduced when it propagates through a weakly ionized plasma, the major question associated with the research is whether the reduction in shock wave intensity is due to the plasma or the concomitant heating of the flow by the plasma generator. The goal of this paper is to describe a temperature compensated experiment in a "large" diameter shock tube with an external heating source, used to control the temperature in the shock tube independently of the plasma density.

  11. Shock-wave-induced flow past a circular cylinder in a dusty-gas shock tube

    NASA Astrophysics Data System (ADS)

    Sugiyama, Hiromu; Shirota, Takahiro; Doi, Hiromichi; Takayama, Kazuyoshi

    1990-05-01

    An experimental investigation of a shock-wave-induced flow past a circular cylinder in a dusty-gas shock tube was made. The shock tubes used for the present research had test sections of identical geometry. For a frozen-shock Mach number of 1.3, flow visualization studies were conducted by the schlieren method, using a high-speed camera and a pulsed-laser holographic interferometer. The behavior of shock waves past a circular cylinder in a dusty-gas, the development of dust-free regions, and the formation of vortices behind a circular cylinder were observed in detail.

  12. Optical observation of shock waves and cavitation bubbles in high intensity laser-induced shock processes.

    PubMed

    Martí-López, L; Ocaña, R; Porro, J A; Morales, M; Ocaña, J L

    2009-07-01

    We report an experimental study of the temporal and spatial dynamics of shock waves, cavitation bubbles, and sound waves generated in water during laser shock processing by single Nd:YAG laser pulses of nanosecond duration. A fast ICCD camera (2 ns gate time) was employed to record false schlieren photographs, schlieren photographs, and Mach-Zehnder interferograms of the zone surrounding the laser spot site on the target, an aluminum alloy sample. We recorded hemispherical shock fronts, cylindrical shock fronts, plane shock fronts, cavitation bubbles, and phase disturbance tracks.

  13. Plasma Shock Wave Modification Experiments in a Temperature Compensated Shock Tube

    NASA Technical Reports Server (NTRS)

    Vine, Frances J.; Mankowski, John J.; Saeks, Richard E.; Chow, Alan S.

    2003-01-01

    A number of researchers have observed that the intensity of a shock wave is reduced when it passes through a weakly ionized plasma. While there is little doubt that the intensity of a shock is reduced when it propagates through a weakly ionized plasma, the major question associated with the research is whether the reduction in shock wave intensity is due to the plasma or the concomitant heating of the flow by the plasma generator. The goal of this paper is to describe a temperature compensated experiment in a "large" diameter shock tube with an external heating source, used to control the temperature in the shock tube independently of the plasma density.

  14. Shock wave convergence in water with parabolic wall boundaries

    SciTech Connect

    Yanuka, D.; Shafer, D.; Krasik, Ya.

    2015-04-28

    The convergence of shock waves in water, where the cross section of the boundaries between which the shock wave propagates is either straight or parabolic, was studied. The shock wave was generated by underwater electrical explosions of planar Cu wire arrays using a high-current generator with a peak output current of ∼45 kA and rise time of ∼80 ns. The boundaries of the walls between which the shock wave propagates were symmetric along the z axis, which is defined by the direction of the exploding wires. It was shown that with walls having a parabolic cross section, the shock waves converge faster and the pressure in the vicinity of the line of convergence, calculated by two-dimensional hydrodynamic simulations coupled with the equations of state of water and copper, is also larger.

  15. SHOCK-WAVE THERAPY APPLICATION IN CLINICAL PRACTICE (REVIEW).

    PubMed

    Sheveleva, N; Minbayeva, L; Belyayeva, Y

    2016-03-01

    The article presents literature review on the use of extracorporeal shock-wave therapy in physiotherapeutic practice. The basic mechanisms of shock waves influence on the organism are spotlighted. Studies proving high efficacy of the method in treatment of wide variety of inflammatory diseases and traumatic genesis are presented. The data on comparative assessment of shock-wave therapy efficacy, and results of researches on possibility of extracorporeal shock-wave therapy effect potentiating in combination with other therapeutic methods are reflected. Recent years, the range of indications for shock-wave therapy application had been significantly widened. However, further study of the method is still relevant because mechanisms of action of the factor are studied insufficiently; methods of therapy parameters selection (energy flux density, number of pulses per treatment, duration of a course) are either advisory or empirical.

  16. Shock waves in noble gases and their mixtures

    NASA Astrophysics Data System (ADS)

    Bratos, M.; Herczynski, R.

    The shock wave structures in pure monatomic gases and in binary gas mixtures are investigated in this paper using a variational approach. The idea of Mott-Smith's distribution function (generalized in the case of a gas mixture) was combined with Tamm's method of solving the Boltzmann equation. The intermolecular potential used is of the Lennard-Jones type. The relation between the dimensionless shock wave thickness and Mach number in front of the shock wave is analyzed. Special attention was paid to the determination of shock wave structures in mixtures of gases with disparate molecular masses. The calculation performed for the shock wave in the binary gas mixture, xenon-helium, confirm the existence of a 'hump' of the density profile of the lighter component. The heavy gas component temperature overshoots its downstream equilibrium value in the case of a mixture of gases with disparate molecular masses and for a small mole fraction of the heavy gas component.

  17. Viscous Shear Layers Formed by Non-Bifurcating Shock Waves in Shock-Tubes

    NASA Astrophysics Data System (ADS)

    Grogan, Kevin; Ihme, Matthias

    2015-11-01

    Shock-tubes are test apparatuses that are used extensively for chemical kinetic measurements. Under ideal conditions, shock-tubes provide a quiescent region behind a reflected shock wave where combustion may take place without complications arising from gas-dynamic effects. However, due to the reflected shock wave encountering a boundary layer, significant inhomogeneity may be introduced into the test region. The bifurcation of the reflected shock-wave is well-known to occur under certain conditions; however, a viscous shear layer may form behind a non-bifurcating reflected shock wave as well and may affect chemical kinetics and ignition of certain fuels. The focus of this talk is on the development of the viscous shear layer and the coupling to the ignition in the regime corresponding to the negative temperature conditions.

  18. CME-Sheath and Shock Heating by Surface Alfven Wave Dissipation in the Lower Corona

    NASA Astrophysics Data System (ADS)

    Evans, R.; Opher, M.; van der Holst, B.

    2011-12-01

    We use the new solar corona component of the Space Weather Modeling Framework (van der Holst et al. 2010), in which the Alfven wave energy evolution is coupled self-consistently to the magnetohydrodynamic equations, to study the evolution of a coronal mass ejection (CME) and the shock it drives in the lower corona (2-8Rs). In this solar wind model, the wave pressure gradient accelerates the wind, and wave dissipation heats the wind. Kolmogorov-like dissipation and surface Alfven wave damping are considered for the dissipation of the waves (Evans et al. 2011). We use a modified Titov-Demoulin flux rope to initiate an eruption, and include magnetogram data from CR2029 (May 2005) as a boundary condition for the coronal magnetic field. Synthetic white light images from the simulation are used to determine the lateral expansion. We show that the expansion of the flux rope leads to the concentration of wave energy at the shock and in the sheath region. The expansion also creates a piled-up compression (PUC) region of plasma density at the back of the sheath, strongest at the flanks of the CME. The wave energy concentrated at the shock and sheath is dissipated by surface Alfven wave damping due to the density gradients, which heats the sheath. We present analysis of the momentum exchange between the solar wind and the waves, and discuss the effect of wave dissipation on the CME evolution.

  19. Shock Wave-Induced Damage of a Protein by Void Collapse

    PubMed Central

    Lau, Edmond Y.; Berkowitz, Max L.; Schwegler, Eric

    2016-01-01

    In this study, we report on a series of molecular dynamics simulations that were used to examine the effects of shock waves on a membrane-bound ion channel. A planar shock wave was found to compress the ion channel upon impact, but the protein geometry resembles the crystal structure as soon as the solvent density begins to dissipate. When a void was placed in close proximity to the membrane, the shock wave proved to be more destructive to the protein due to formation of a nanojet that results from the asymmetric collapse of the void. The nanojet was able to cause significant structural changes to the protein even at low piston velocities that are not able to directly cause poration of the membrane. PMID:26745418

  20. Shock Wave-Induced Damage of a Protein by Void Collapse.

    PubMed

    Lau, Edmond Y; Berkowitz, Max L; Schwegler, Eric

    2016-01-05

    In this study, we report on a series of molecular dynamics simulations that were used to examine the effects of shock waves on a membrane-bound ion channel. A planar shock wave was found to compress the ion channel upon impact, but the protein geometry resembles the crystal structure as soon as the solvent density begins to dissipate. When a void was placed in close proximity to the membrane, the shock wave proved to be more destructive to the protein due to formation of a nanojet that results from the asymmetric collapse of the void. The nanojet was able to cause significant structural changes to the protein even at low piston velocities that are not able to directly cause poration of the membrane. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  1. Dispersive shock wave interactions and asymptotics.

    PubMed

    Ablowitz, Mark J; Baldwin, Douglas E

    2013-02-01

    Dispersive shock waves (DSWs) are physically important phenomena that occur in systems dominated by weak dispersion and weak nonlinearity. The Korteweg-de Vries (KdV) equation is the universal model for systems with weak dispersion and weak, quadratic nonlinearity. Here we show that the long-time-asymptotic solution of the KdV equation for general, steplike data is a single-phase DSW; this DSW is the "largest" possible DSW based on the boundary data. We find this asymptotic solution using the inverse scattering transform and matched-asymptotic expansions. So while multistep data evolve to have multiphase dynamics at intermediate times, these interacting DSWs eventually merge to form a single-phase DSW at large time.

  2. Augmented shock wave fracture/severance of materials

    NASA Technical Reports Server (NTRS)

    Schimmel, Morry L. (Inventor); Bement, Laurence J. (Inventor)

    1995-01-01

    The present invention related generally to severing materials, and more particularly to severing or weakening materials through explosively induced, augmented shock waves. Explosive cords are placed in grooves on the upper surface of the material to be severed or weakened. The explosive cords are initiated simultaneously to introduce explosive shock waves into the material. These shock waves progress toward the centerline between the explosive cords and the lower surface of the material. Intersecting and reflected waves produce a rarefaction zone on the centerline to fail the material in tension. A groove may also be cut in the lower surface of the material to aid in severing or weakening the material.

  3. Reflection of a plane shock wave from a slit

    NASA Astrophysics Data System (ADS)

    Serov, A. O.; Shtemenko, L. S.; Shugaev, F. V.

    Laser shadow photography was used in a shock-tube visualization study of a plane shock wave reflected from a slit. The working gases were air and Freon 14, and the Mach number of the incident shock wave was in the 2-3 range. An intense interaction between the reflected wave and the walls of the slit was observed. This interaction could lead to the disappearance of the rectilinear part of this wave, thus reducing the load experienced by the body during this type of reflection.

  4. Optical Radiation from Shock-Compressed Materials. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Svendsen, Robert F., Jr.

    1987-01-01

    Recent observations of shock-induced radiation from oxides, silicates, and metals of geophysical interest constrain the shock-compressed temperature of these materials. The relationships between the temperature inferred from the observed radiation and the temperature of the shock-compressed film or foil and/or window were investigated. Changes of the temperature field in each target component away from that of their respective shock-compressed states occur because of: shock-impedance mismatch between target components; thermal mismatch between target components; surface roughness at target interfaces; and conduction within and between target components. In particular, conduction may affect the temperature of the film/foil window interface on the time scale of the experiments, and so control the intensity and history of the dominant thermal radiation sources in the target. This type of model was used to interpret the radiation emitted by a variety of shock-compressed materials and interfaces.

  5. The physical mechanisms of subcritical collisionless shock-wave formation

    NASA Technical Reports Server (NTRS)

    Mellott, M. M.

    1984-01-01

    The key process in shock wave formation is related to energy dissipation, and the nature of the operative dissipation mechanism determines the basic character of the resulting shock. In the case of collisionless plasmas, the primary problem consists in the identification of the processes which can provide the necessary dissipation in relatively short spatial scale lengths. The present investigation is concerned with the various collisionless dissipation mechanisms which can operate in weak shocks, taking into account the effects of different mechanisms on shock structure. Particular attention is given to a restricted class of quasi-perpendicular low beta low Mach number shocks. Such shocks are traditionally called 'laminar shocks'. Resistive shocks are considered along with subcritical shocks observed with the aid of the ISEE spacecraft.

  6. Small scales formation via Alfven wave propagation in compressible nonuniform media

    NASA Technical Reports Server (NTRS)

    Malara, F.; Primavera, L.; Veltri, P.

    1995-01-01

    In weakly dissipative media governed by the magnetohydrodynamics (MHD) equations, any efficient mechanism of energy dissipation requires the formation of small scales. The possibility to produce small scales has been studied by Malara et al. in the case of MHD disturbances propagating in an incompressible and inhomogeneous medium, for a strictly 2D geometry. We extend the work of Malara et al. to include both compressibility and the third component for vector quantities. Using numerical simulations we show that, when an Alfven wave propagates in a compressible nonuniform medium, the two dynamical effects responsible for the small scales formation in the incompressible case are still at work: energy pinching and phase-mixing. Moreover, the interaction between the initial Alfven wave and the inhomogeneity gives rise to the formation of compressible perturbations (fast and slow waves or a static entropy wave). Some of these compressive fluctuations are subject to the steepening of the wave front and become shock waves, which are extremely efficient in dissipating their energy, their dissipation being independent of the Reynolds number. A rough estimate of the typical times which the various dynamical processes take to produce small scales and then to dissipate the energy show that these times are consistent with those required to dissipate inside the solar corona the energy of Alfven waves of photospheric origin.

  7. Small scales formation via Alfven wave propagation in compressible nonuniform media

    NASA Technical Reports Server (NTRS)

    Malara, F.; Primavera, L.; Veltri, P.

    1995-01-01

    In weakly dissipative media governed by the magnetohydrodynamics (MHD) equations, any efficient mechanism of energy dissipation requires the formation of small scales. The possibility to produce small scales has been studied by Malara et al. in the case of MHD disturbances propagating in an incompressible and inhomogeneous medium, for a strictly 2D geometry. We extend the work of Malara et al. to include both compressibility and the third component for vector quantities. Using numerical simulations we show that, when an Alfven wave propagates in a compressible nonuniform medium, the two dynamical effects responsible for the small scales formation in the incompressible case are still at work: energy pinching and phase-mixing. Moreover, the interaction between the initial Alfven wave and the inhomogeneity gives rise to the formation of compressible perturbations (fast and slow waves or a static entropy wave). Some of these compressive fluctuations are subject to the steepening of the wave front and become shock waves, which are extremely efficient in dissipating their energy, their dissipation being independent of the Reynolds number. A rough estimate of the typical times which the various dynamical processes take to produce small scales and then to dissipate the energy show that these times are consistent with those required to dissipate inside the solar corona the energy of Alfven waves of photospheric origin.

  8. Observations of a Coronal Shock Wave and the Production of Solar Energetic Particles

    NASA Astrophysics Data System (ADS)

    Xu, Z. G.; Li, C.; Ding, M. D.

    2017-05-01

    We present a study that clarifies the acceleration source/mechanism of the solar energetic particle (SEP) event on 2011 August 9. Based on the assumption of scatter-free propagation of charged particles along the interplanetary magnetic field, the solar particle release times of the electrons and protons are derived and both found to be in the decay phase of the flare emission. Furthermore, we compare the peak-flux spectra of the in situ particles and the remote-sensing hard X-ray photons and find a weak correlation between them. In particular, we note that an extreme ultraviolet shock wave, presumed to be a signature of coronal mass ejection (CME) shock front on the solar surface, and an associated type II radio burst were observed alongside this event. Under the framework of diffusive shock acceleration, the derived shock compression ratio can accelerate particles with a theoretical spectral index γ ={2.14}-0.02+0.01, which is comparable to the observational index of ˜2.0. Our results appear to support the notion that the coronal shock wave was most likely responsible for the SEP event. Specifically, we find that the electrons were released in a low coronal site at ˜0.58 solar radii, and protons were released when the CME-driven shock propagated to ˜1.38 solar radii. The multi-spacecraft observations, in addition, reveal the connection between the acceleration of shock waves and the release of SEPs.

  9. Cytoplasmic molecular delivery with shock waves: importance of impulse.

    PubMed

    Kodama, T; Hamblin, M R; Doukas, A G

    2000-10-01

    Cell permeabilization using shock waves may be a way of introducing macromolecules and small polar molecules into the cytoplasm, and may have applications in gene therapy and anticancer drug delivery. The pressure profile of a shock wave indicates its energy content, and shock-wave propagation in tissue is associated with cellular displacement, leading to the development of cell deformation. In the present study, three different shock-wave sources were investigated; argon fluoride excimer laser, ruby laser, and shock tube. The duration of the pressure pulse of the shock tube was 100 times longer than the lasers. The uptake of two fluorophores, calcein (molecular weight: 622) and fluorescein isothiocyanate-dextran (molecular weight: 71,600), into HL-60 human promyelocytic leukemia cells was investigated. The intracellular fluorescence was measured by a spectrofluorometer, and the cells were examined by confocal fluorescence microscopy. A single shock wave generated by the shock tube delivered both fluorophores into approximately 50% of the cells (p < 0.01), whereas shock waves from the lasers did not. The cell survival fraction was >0.95. Confocal microscopy showed that, in the case of calcein, there was a uniform fluorescence throughout the cell, whereas, in the case of FITC-dextran, the fluorescence was sometimes in the nucleus and at other times not. We conclude that the impulse of the shock wave (i.e., the pressure integrated over time), rather than the peak pressure, was a dominant factor for causing fluorophore uptake into living cells, and that shock waves might have changed the permeability of the nuclear membrane and transferred molecules directly into the nucleus.

  10. Cytoplasmic molecular delivery with shock waves: importance of impulse.

    PubMed Central

    Kodama, T; Hamblin, M R; Doukas, A G

    2000-01-01

    Cell permeabilization using shock waves may be a way of introducing macromolecules and small polar molecules into the cytoplasm, and may have applications in gene therapy and anticancer drug delivery. The pressure profile of a shock wave indicates its energy content, and shock-wave propagation in tissue is associated with cellular displacement, leading to the development of cell deformation. In the present study, three different shock-wave sources were investigated; argon fluoride excimer laser, ruby laser, and shock tube. The duration of the pressure pulse of the shock tube was 100 times longer than the lasers. The uptake of two fluorophores, calcein (molecular weight: 622) and fluorescein isothiocyanate-dextran (molecular weight: 71,600), into HL-60 human promyelocytic leukemia cells was investigated. The intracellular fluorescence was measured by a spectrofluorometer, and the cells were examined by confocal fluorescence microscopy. A single shock wave generated by the shock tube delivered both fluorophores into approximately 50% of the cells (p < 0.01), whereas shock waves from the lasers did not. The cell survival fraction was >0.95. Confocal microscopy showed that, in the case of calcein, there was a uniform fluorescence throughout the cell, whereas, in the case of FITC-dextran, the fluorescence was sometimes in the nucleus and at other times not. We conclude that the impulse of the shock wave (i.e., the pressure integrated over time), rather than the peak pressure, was a dominant factor for causing fluorophore uptake into living cells, and that shock waves might have changed the permeability of the nuclear membrane and transferred molecules directly into the nucleus. PMID:11023888

  11. Investigations of Compression Shocks and Boundary Layers in Gases Moving at High Speed

    NASA Technical Reports Server (NTRS)

    Ackeret, J.; Feldmann, F.; Rott, N.

    1947-01-01

    The mutual influences of compression shocks and friction boundary layers were investigated by means of high speed wind tunnels.Schlieren optics provided a clear picture of the flow phenomena and were used for determining the location of the compression shocks, measurement of shock angles, and also for Mach angles. Pressure measurement and humidity measurements were also taken into consideration.Results along with a mathematical model are described.

  12. The influence of incident shock Mach number on radial incident shock wave focusing

    NASA Astrophysics Data System (ADS)

    Chen, Xin; Tan, Sheng; He, Liming; Rong, Kang; Zhang, Qiang; Zhu, Xiaobin

    2016-04-01

    Experiments and numerical simulations were carried out to investigate radial incident shock focusing on a test section where the planar incident shock wave was divided into two identical ones. A conventional shock tube was used to generate the planar shock. Incident shock Mach number of 1.51, 1.84 and 2.18 were tested. CCD camera was used to obtain the schlieren photos of the flow field. Third-order, three step strong-stability-preserving (SSP) Runge-Kutta method, third-order weighed essential non-oscillation (WENO) scheme and adaptive mesh refinement (AMR) algorithm were adopted to simulate the complicated flow fields characterized by shock wave interaction. Good agreement between experimental and numerical results was observed. Complex shock wave configurations and interactions (such as shock reflection, shock-vortex interaction and shock focusing) were observed in both the experiments and numerical results. Some new features were observed and discussed. The differences of structure of flow field and the variation trends of pressure were compared and analyzed under the condition of different Mach numbers while shock wave focusing.

  13. Biological effects of tandem shock waves demonstrated on magnetic resonance.

    PubMed

    Benes, J; Zeman, J; Pouckova, P; Zadinova, M; Sunka, P; Lukes, P

    2012-01-01

    The shock wave is used for the treatment of kidney stones, eventually of gall stones, for more than 20 years. It is a pressure wave, which breaks through soft tissues easily and it is possible to focus it into a small volume. The excellent results of the treatment of concrements led to considerations about another usage of the shock wave. The research is now concentrated on the possibility of the damage to tumour tissues. In contrast to concrements tumour tissues are not different from healthy tissues as for their acoustic attributes. That is why a new source of shock waves was used in this work. The source allows generating two successive shock waves focused into a common focus, so-called tandem shock waves. The biological effects of the tandem shock waves generated by the new source on rats hepatic tissue and rabbit femoral muscle in vivo were studied in this work. The damage is demonstrated by magnetic resonance imaging. MR images showed tissue damage in focus. There was damage of the liver tissue, muscle and also stomach wall. We found that the tandem shock waves are able to damage the acoustically homogeneous soft tissue in the focus, i.e. in the depth. In tissues in front of the focus, there is, however, no damage (Fig. 10, Ref. 15).

  14. August Toepler — The first who visualized shock waves

    NASA Astrophysics Data System (ADS)

    Krehl, P.; Engemann, S.

    1995-06-01

    The scientific investigation of the nature of shock waves started 130 years ago with the advent of the schlieren method which was developed in the period 1859 1864 by August Toepler. At the very beginning applied to the visualization of heat and flow phenomena, he immediately turned to air shock waves generated by electric sparks, and subjectively studied the propagation, reflection and refraction of shock waves. His new delay circuit in the microsecond time regime for the first time made it possible to vary electrically the delay time between a spark generating a shock wave and a second spark acting as a flash light source in his chlieren setup. In 1870 Toepler, together with Boltzmann, applied Jamin's interferometric refractometer and extended the visualization to very weak sound waves at the threshold of hearing. Toepler's pioneering schlieren method stimulated Ernst Mach and his team to objectively investigate the nature of shock waves: they improved Toepler's time delay circuit; continued the study on the reflection of shock waves; introduced shadowgraphy as a modification of the schlieren method; photographed the propagation of shock waves generated by an electric spark and by supersonic projectiles, and improved interferometry. Based on a large number of original documents the paper illuminates the concomitant circumstances of the invention of the schlieren method and its first applications by others.

  15. Microstructure and Mechanical Properties After Shock Wave Loading of Cast CrMnNi TRIP Steel

    NASA Astrophysics Data System (ADS)

    Eckner, Ralf; Krüger, L.; Ullrich, C.; Rafaja, D.; Schlothauer, T.; Heide, G.

    2016-10-01

    The mechanical response of shock wave-prestrained high-alloy Cr16-Mn7-Ni6 TRIP steel was investigated under compressive and tensile loading at room temperature. Previous shock wave loading was carried out using a flyer-plate assembly with different amounts of explosives in order to achieve shock pressures of 0.3, 0.6, 0.9, and 1.2 Mbar. A significant increase in hardness and strength was observed as compared with the initial as-cast condition. In contrast, a slight decrease in strain hardening rates was measured together with a decrease in fracture elongation in the tensile test. Microstructural analyses of the shock-loaded samples were performed by light optical and scanning electron microscopy. The microstructure revealed a high density of deformation bands consisting of separated stacking faults, ɛ-martensite, or twins. Significant amounts of deformation-induced α'-martensite were only present at the highest shock pressure of 1.2 Mbar. The thickness of the deformation bands and the number of martensite nuclei at their intersections increased with increasing shock pressure. In all shock-loaded specimens, pronounced phase transformation occurred during subsequent mechanical testing. Consequently, the amount of the deformation-induced α'-martensite in the shock-loaded specimens was higher than in the unshocked as-cast samples.

  16. Molecular dynamics simulations of shock waves in hydroxyl-terminated polybutadiene melts: mechanical and structural responses.

    PubMed

    Fröhlich, Markus G; Sewell, Thomas D; Thompson, Donald L

    2014-01-14

    The mechanical and structural responses of hydroxyl-terminated cis-1,4-polybutadiene melts to shock waves were investigated by means of all-atom non-reactive molecular dynamics simulations. The simulations were performed using the OPLS-AA force field but with the standard 12-6 Lennard-Jones potential replaced by the Buckingham exponential-6 potential to better represent the interactions at high compression. Monodisperse systems containing 64, 128, and 256 backbone carbon atoms were studied. Supported shock waves were generated by impacting the samples onto stationary pistons at impact velocities of 1.0, 1.5, 2.0, and 2.5 km s(-1), yielding shock pressures between approximately 2.8 GPa and 12.5 GPa. Single-molecule structural properties (squared radii of gyration, asphericity parameters, and orientational order parameters) and mechanical properties (density, shock pressure, shock temperature, and shear stress) were analyzed using a geometric binning scheme to obtain spatio-temporal resolution in the reference frame centered on the shock front. Our results indicate that while shear stress behind the shock front is relieved on a ∼0.5 ps time scale, a shock-induced transition to a glass-like state occurs with a concomitant increase of structural relaxation times by several orders of magnitude.

  17. Molecular dynamics simulations of shock waves in hydroxyl-terminated polybutadiene melts: Mechanical and structural responses

    NASA Astrophysics Data System (ADS)

    Fröhlich, Markus G.; Sewell, Thomas D.; Thompson, Donald L.

    2014-01-01

    The mechanical and structural responses of hydroxyl-terminated cis-1,4-polybutadiene melts to shock waves were investigated by means of all-atom non-reactive molecular dynamics simulations. The simulations were performed using the OPLS-AA force field but with the standard 12-6 Lennard-Jones potential replaced by the Buckingham exponential-6 potential to better represent the interactions at high compression. Monodisperse systems containing 64, 128, and 256 backbone carbon atoms were studied. Supported shock waves were generated by impacting the samples onto stationary pistons at impact velocities of 1.0, 1.5, 2.0, and 2.5 km s-1, yielding shock pressures between approximately 2.8 GPa and 12.5 GPa. Single-molecule structural properties (squared radii of gyration, asphericity parameters, and orientational order parameters) and mechanical properties (density, shock pressure, shock temperature, and shear stress) were analyzed using a geometric binning scheme to obtain spatio-temporal resolution in the reference frame centered on the shock front. Our results indicate that while shear stress behind the shock front is relieved on a ˜0.5 ps time scale, a shock-induced transition to a glass-like state occurs with a concomitant increase of structural relaxation times by several orders of magnitude.

  18. Molecular dynamics simulations of shock waves in hydroxyl-terminated polybutadiene melts: Mechanical and structural responses

    SciTech Connect

    Fröhlich, Markus G. E-mail: ThompsonDon@missouri.edu; Sewell, Thomas D. Thompson, Donald L. E-mail: ThompsonDon@missouri.edu

    2014-01-14

    The mechanical and structural responses of hydroxyl-terminated cis-1,4-polybutadiene melts to shock waves were investigated by means of all-atom non-reactive molecular dynamics simulations. The simulations were performed using the OPLS-AA force field but with the standard 12-6 Lennard-Jones potential replaced by the Buckingham exponential-6 potential to better represent the interactions at high compression. Monodisperse systems containing 64, 128, and 256 backbone carbon atoms were studied. Supported shock waves were generated by impacting the samples onto stationary pistons at impact velocities of 1.0, 1.5, 2.0, and 2.5 km s{sup −1}, yielding shock pressures between approximately 2.8 GPa and 12.5 GPa. Single-molecule structural properties (squared radii of gyration, asphericity parameters, and orientational order parameters) and mechanical properties (density, shock pressure, shock temperature, and shear stress) were analyzed using a geometric binning scheme to obtain spatio-temporal resolution in the reference frame centered on the shock front. Our results indicate that while shear stress behind the shock front is relieved on a ∼0.5 ps time scale, a shock-induced transition to a glass-like state occurs with a concomitant increase of structural relaxation times by several orders of magnitude.

  19. Simplified laser-driven flyer plates for shock compression science

    NASA Astrophysics Data System (ADS)

    Brown, Kathryn E.; Shaw, William L.; Zheng, Xianxu; Dlott, Dana D.

    2012-10-01

    We describe a simplified system of laser-driven flyer plates for shock compression science and shock spectroscopy. We used commercially available one-box Nd:YAG lasers and beam homogenization solutions to create two launch systems, one based on a smaller (400 mJ) YAG laser and an inexpensive diffusive optic, and one based on a larger (2500 mJ) laser and a diffractive beam homogenizer. The flyer launch, flight, and impact processes were characterized by an 8 GHz fiberoptic photon Doppler velocimeter. We investigated effects of different substrates, adhesives, absorbers, ablative layers, and punching out disks from continuous foils versus fabricating individual foil disks, and found that a simple metal foil epoxied to a glass window was satisfactory in almost all cases. Our simplified system launched flyer plates with velocities up to 4.5 km s-1 and kinetic energies up to 250 mJ that can drive sustained steady shocks for up to 25 ns. The factor that limits these velocities and energies is the laser fluence that can be transmitted through the glass substrate to the flyer surface without optical damage. Methods to increase this transmission are discussed. Reproducible flyer launches were demonstrated with velocity variations of 0.06% and impact time variations of 1 ns. The usefulness of this flyer plate system is demonstrated by Hugoniot equation of state measurements of a polymer film, emission spectroscopy of a dye embedded in the polymer, and impact initiation and emission spectroscopy of a reactive material consisting of nanoscopic fuel and oxidizer particles.

  20. Simplified laser-driven flyer plates for shock compression science.

    PubMed

    Brown, Kathryn E; Shaw, William L; Zheng, Xianxu; Dlott, Dana D

    2012-10-01

    We describe a simplified system of laser-driven flyer plates for shock compression science and shock spectroscopy. We used commercially available one-box Nd:YAG lasers and beam homogenization solutions to create two launch systems, one based on a smaller (400 mJ) YAG laser and an inexpensive diffusive optic, and one based on a larger (2500 mJ) laser and a diffractive beam homogenizer. The flyer launch, flight, and impact processes were characterized by an 8 GHz fiberoptic photon Doppler velocimeter. We investigated effects of different substrates, adhesives, absorbers, ablative layers, and punching out disks from continuous foils versus fabricating individual foil disks, and found that a simple metal foil epoxied to a glass window was satisfactory in almost all cases. Our simplified system launched flyer plates with velocities up to 4.5 km s(-1) and kinetic energies up to 250 mJ that can drive sustained steady shocks for up to 25 ns. The factor that limits these velocities and energies is the laser fluence that can be transmitted through the glass substrate to the flyer surface without optical damage. Methods to increase this transmission are discussed. Reproducible flyer launches were demonstrated with velocity variations of 0.06% and impact time variations of 1 ns. The usefulness of this flyer plate system is demonstrated by Hugoniot equation of state measurements of a polymer film, emission spectroscopy of a dye embedded in the polymer, and impact initiation and emission spectroscopy of a reactive material consisting of nanoscopic fuel and oxidizer particles.