Impact Of Shock Wave Research Articles

The interaction of the projectile with moving plates and rods

The study of the problem of protecting the elements of constructions from impact loadings is very important due to the need of constant perfection of the means of shock-wave impact on the objects of modern technology. The problem of creating a reliable protective system dictates necessity of studying different ways to counteract to high-velocity elongated projectiles. The interaction of projectiles with plates and rods which are thrown towards by HE is investigated. The strain and fracture of the projectile sharply reduce its penetrating ability.

EOR (Oil Recovery Enhancement) Technology Using Shock Wave in the Fluid

In this research the alternative method is presented increases of oil recovery of an oil collector. Shock wave impact on layer. The technology is developed, advantage of this method is shown in comparison with layer hydraulic fracturing. For increase oil recovery and restoration of wells the traditional is widely applied technology of hydraulic fracturing of layer (flyuding), allowing on the short period to recover a well. Sense of a flyuding that hydrostatic pressure is created is considerable exceeding mountain and bringing to a rupture of a collector on one or several cracks. In this work the alternative technique of increase in oil recovery is offered by creation of a shock wave small intensity in the bottom fluid. With a high frequency of repeatability set of blows increases quantity of micro cracks in collector rock, increasing coefficient of permeability of layer without breaking its connectivity.

Influence of the nonequilibrium phase transition on the collapse of inertia nonspherical bubbles in a compressible liquid

In this work, we investigate the shock wave–inertial vapor bubble interactions by taking the nonequilibrium phase transition at the interface, fluid compressibility, and axisymmetric bubble deformations including jet penetration into account. We use the level set method (Sussman et al., 1994) and the ghost fluid method (Fedkiw et al., 1999), which were improved so as to consider the nonequilibrium phase transition (Jinbo & Takahira, 2012). The numerical treatments for heat and mass fluxes through interfaces due to the phase transition are implemented, satisfying the conservation laws of mass, momentum, and energy at the interface and preventing the interface from becoming diffused. The influence of surface tension is also considered in the method. The improved method is applied to the shock–bubble interaction under the experimental conditions by Sankin et al. (2005). The pressure waveform of the incident shock wave is comprised of a leading compressive wave with a peak pressure of 39MPa and a pulse duration of around 1μs, followed by a trailing tensile wave of −8MPa in peak pressure with a pulse duration of around 2μs which is determined from the experiment. The liquid-jet formation and the generation of shock waves from the collapsing nonspherical bubble are simulated successfully by taking the nonequilibrium phase transition and surface tension into account. The validity of the simulation is shown by comparing the numerical results (e.g. the intensity of the shock wave generated by the bubble collapse and displacement of the bubble centroid) with those obtained from the experiments (Sankin et al., 2005; Klaseboer et al., 2007). We investigate the effects of the phase of bubble oscillations when the incident shock wave impinges on the spherically-shrinking bubble, on the shock wave radiated from the bubble collapse. It is also shown that when the nonequilibrium phase transition at the interface of nonspherically collapsing bubbles is considered, the minimum bubble radius and the maximum space-averaged pressure value inside the bubble reached during its collapse decreases and increases, respectively, compared with those in the case without the phase transition.

Structure Dynamic Response Analysis of Pipe String under the Action of Perforating Detonation Wave

Impact load of perforation will result in strong vibration of downhole string, string operated such as bending fracture accidents. Considering the clearance between string and casing, using space beam and spring element to solve the nonlinear contact problems between oil jacket, established the numerical model of string structure dynamic response analysis in horizontal well. Extracting downhole perforation pressure wave monitoring data, using the finite element software ANSYS, analyzed the dynamic response of the tubing under perforation of detonation shock wave impact, got the displacement of the tubing、acceleration time history. The results show that, without packer, the maximum Mises equivalent stress in the end of the string, the deformation and stress changes in deflecting section of the tubing string are bigger than in vertical Wells.

Generation of negative pressures and spallation phenomena in diamond exposed to a picosecond laser pulse

The spallation phenomena in poly- and single-crystal synthetic diamonds have been experimentally investigated. A shock-wave impact on a target was implemented using a laser pulse in the Kamerton-T facility. The ablation pressure of on the front target surface was formed by pulsed radiation of a neodymium phosphate glass laser (second harmonic , pulse energy ) with an intensity as high as . The maximum diamond spall strength is found to be 24 % of the theoretical ultimate strength. Raman scattering data indicate that a small amount of crystalline diamond in the spallation region on the rear side of the target is graphitised.

Shock tunnel experiments on control of shock induced large separation bubble using boundary layer bleed

Shock–Boundary Layer Interaction (SBLI) often occurs in supersonic/hypersonic flow fields. Especially when accompanied by separation (termed strong interaction), the SBLI phenomena largely affect the performance of the systems where they occur, such as scramjet intakes, thus often demanding the control of the interaction. Experiments on the strong interaction between impinging shock wave and boundary layer on a flat plate at Mach 5.96 are carried out in IISc hypersonic shock tunnel HST-2. The experiments are performed at moderate flow total enthalpy of 1.3 MJ/kg and freestream Reynolds number of 4 million/m. The strong shock generated by a wedge (or shock generator) of large angle 30.96° to the freestream is made to impinge on the flat plate at 95 mm (inviscid estimate) from the leading edge, due to which a large separation bubble of length (75 mm) comparable to the distance of shock impingement from the leading edge is generated. The experimental simulation of such large separation bubble with separation occurring close to the leading edge, and its control using boundary layer bleed (suction and tangential blowing) at the location of separation, are demonstrated within the short test time of the shock tunnel (∼600 μs) from time resolved schlieren flow visualizations and surface pressure measurements. By means of suction – with mass flow rate one order less than the mass flow defect in boundary layer – a reduction in separation length by 13.33% was observed. By the injection of an array of (nearly) tangential jets in the direction of mainstream (from the bottom of the plate) at the location of separation – with momentum flow rate one order less than the boundary layer momentum flow defect – 20% reduction in separation length was observed, although the flow field was apparently unsteady.

Numerical investigation of gas dynamics in nozzles of small-dimensioned gas generators and flowing out jets

The paper presents the statement of the problem of numerical simulation of gas dynamics of nozzles and jets of small-dimensioned gas generators of supersonic flows based on boundary layer and Navier-Stokes equations and the results of solving it. The results of the numerical studies of gas dynamics of nozzles and jets for standard small-dimensioned gas generators with a thrust 6 N and 12 N are given. Significant potential of increasing specific impulse by optimizing the contour of supersonic nozzles of small-dimensioned gas generators are exhibited. The process of shock wave formation in the supersonic part of the nozzle of a standard smalldimensioned gas generator is numerically investigated. Significant impact of shock waves on the gas dynamics of vacuum jets is illustrated.

Collision of an interplanetary shock wave with the Earth’s bow shock. Hydrodynamic parameters and magnetic field

Hydrodynamic parameters and magnetic field generated in each of the waves in neighborhood of the Earth’s bow shock when an interplanetary shock wave impinges on it and propagates along its surface are found in the three-dimensional non-plane-polarized formulation within the framework of the ideal magnetohydrodynamic model. The interaction pattern is constructed in the quasi-steady-state formulation as a mosaic of exact solutions, obtained by means of a computer, to the Riemann problem of breakdown of a discontinuity between the states downstream of the impinging wave and the bow shock on the traveling line of intersection of their fronts. The calculations are carried out for typical parameters of the quiescent solar wind and the interplanetary magnetic field in the Earth’s orbit when the plane front of a shock wave moves along the Sun-Earth radius with various given velocities. The solutions obtained can be used to interpret measurements carried out by spacecraft in the solar wind and in neighborhood of the Earth’s magnetosphere.

Seismic Characterization of the Chelyabinsk Meteor's Terminal Explosion

Online Material: Figures of waveform fit, apparent source time functions, and video of impact of shock wave at factory. Impacts with our planet cause seismic shaking by a variety of mechanisms. Catastrophic ground motion, even at antipodal distances, can be generated by the extremely infrequent, hypersonic collisions with large asteroids or comets (Meschede et al. , 2011). Fortunately, the atmosphere effectively shields the smaller (and far more common) meteoroids, greatly reducing their initial kinetic energy at high altitude, causing them to slow down, break up, and even vaporize, producing a meteor (Ceplecha and Revelle, 2005). In most instances, the ground shaking is triggered by the atmospheric shock wave of a meteor, not by the impact of the surviving meteorites (Edwards et al. , 2008). A particularly strong shock wave can be generated by explosive fragmentation of the meteoroid in one or several final airbursts (Ceplecha and Revelle, 2005; Edwards et al. , 2008). Such disruptions are triggered when the pressure (ram pressure) caused by atmospheric drag exceeds the internal strength of a meteoroid. They are accompanied by a sudden increase in the meteor luminosity (a flare), because they imply a sharp increase in the surface area being subject to ablation. On 15 February 2013 at 03:20 UTC, an exceptionally large meteor in the region of Chelyabinsk, Russia, produced a powerful shock wave, which caused unprecedented damage to people and property. According to official news reports, glass windows were shattered in over 7300 buildings (some of these even experienced slight structural damage), and falling debris hurt more than 1600 people. The meteorite fragments that survived the atmospheric entry hit the ground at subsonic terminal velocity (Schiermeier, 2013), and did not cause any seismic shaking detectable at regional distances. However, the meteor produced the strongest atmospheric infrasound signal ever recorded (Stone, 2013) and …

Chemotherapy efficiency increase via shock wave interaction with biological membranes: a molecular dynamics study

Application of ultrasound to biological tissues has been identified as a promising cancer treatment technique relying on temporal enhancement of biological membrane permeability via shock wave impact. In the present study, the effects of ultrasonic waves on a 1,2-dipalmitoyl-sn-phosphatidylcholine biological membrane are examined through molecular dynamics simulations. Molecular dynamics methods traditionally employ periodic boundary conditions which, however, restrict the total simulation time to the time required for the shock wave crossing the domain, thus limiting the evaluation of the effects of shock waves on the diffusion properties of the membrane. A novel method that allows capturing both the initial shock wave transit as well as the subsequent longer-timescale diffusion phenomena has been successfully developed, validated and verified via convergence studies. Numerical simulations have been carried out with ultrasonic impulses varying from 0.0 to 0.6 mPa s leading to the conclusion that for impulses ≥0.45 mPa s, no self-recovery of the bilayer is observed and, hence, ultrasound could be applied to the destruction of localized tumor cells. However, for impulses ≤0.3 mPa s, an increase in the transversal diffusivity of the lipids, indicating a consequent enhancement of drug absorption across the membrane, is initially observed followed by a progressive recovery of the initial values, thereby suggesting the advantageous effects of ultrasound on enhancing the chemotherapy efficiency.

Multiphysics Investigation of Composite Shell Structures Subjected to Water Shock Wave Impact in Petroleum Industry

This paper presents the study of dynamic failure mechanisms of composite shell structures subjected to water shock impact loading, used in petroleum industry, by conducting a series of experiments and non-linear numerical analyses. This work provides needed data on the response of composite shell structures and validate numerical methodologies essential for use in future work on fluid-structure interactions in oil and gas industry.

Control of oblique shock wave/boundary layer interactions using plasma actuators

Localized arc filament plasma actuators (LAFPAs) are used for shock wave/boundary layer interaction induced separation control in a Mach 2.3 flow. The boundary layer is fully turbulent with a Reynolds number based on the incompressible momentum thickness of 22,000 and shape factor of 1.37, and the impinging shock wave is generated by a 10° compression ramp. The LAFPAs are observed to have significant control authority over the interaction. The main effect is the displacement of the reflected shock and most of the interaction region upstream by approximately one boundary layer thickness (~5 mm). The initial goal of the control was to manipulate the low-frequency (St~0.03) unsteadiness associated with the interaction region. A detailed investigation of the effect of actuator placement, frequency, and duty cycle on the control authority indicates the actuators’ primary control mechanism is not the manipulation of low-frequency unsteadiness. Detailed measurements and analysis indicate that a modification to the boundary layer through heat addition by the actuators is the control mechanism, despite the extremely small power input of the actuators.

Investigations on high enthalpy shock wave exposed graphitic carbon nanoparticles

The impact of high enthalpy shock wave on graphitic carbon nanoparticle (GCNP) films has been investigated and discussed in view of space and chemical engineering applications. The GCNP films were developed by using spray method and exposed to high enthalpy shock wave under an inert atmosphere. Upon shock wave treatment, two typical amendments such as weight loss in the deposited material and growth of second order nanostructures (SONs) have been observed. While increasing test gas pressure, the loss of material and density of SONs are gradually increased. Most of the shock wave induced SONs are highly crystalline and belong to the cubic diamond structure. Upon shock treatment as well as with increase of test gas pressure, a considerable improvement in the quality of GCNP films has been observed. Further, ablation of GCNPs exclusively on the top surface of the coatings and formation of hierarchical NPs (diamond NPs on GCNPs) has been observed.

Effect of an impinging shock wave on a partially opened door

The behavior of an aluminum door hanging at the exit of an open shock tube at different angles, from 5\(^\circ \) to 85\(^\circ \), and thereby providing partially open space for the exiting flow, was investigated experimentally. Experiments were conducted with an incident shock wave Mach number of \(M_\mathrm{is}=1.1\) impinging on the partially opened door. Both pressure measurements in the vicinity of the door, on its center and inside the shock tube, and schlieren visualization were undertaken for studying the door movement and its maximum opening angle relative to its initial position. It was found that for an initial opening angle smaller than 25\(^\circ \) the door opened completely while for larger angles its motion is marginal. In addition, for an initial door opening angle of about 10\(^\circ \) the lowest pressures were recorded inside the shock tube behind the evolving waves after exiting of the incident shock wave. The present experimental results may be useful to numerical studies of fluid–structure interactions, e.g., in designing safety valves in jet engines. Such a device is needed for preventing rupture in the case when a sudden overpressure pulse is generated inside the aircraft engine compartment.

Specific features of the behaviour of targets under negative pressures created by a picosecond laser pulse

New experimental data are obtained concerning the character of spallation and the mechanical strength of targets made of aluminium, aluminium–magnesium alloy (AMg6M), polymethylmethacrylate (PMMA, plexiglass), tantalum, copper, tungsten, palladium, silicon, and lead under the impact of laser radiation with the duration 70 ps. The specific features of the spallation phenomenon, in which the separation of a part of the target substance occurs at the back surface as a result of the effect of negative pressures (tensile stresses) in the substance, are experimentally studied. To determine the time moment of spallation, the electrocontact method of measuring the velocity of the spalled layer is developed and implemented. The obtained results show that the values of spall strength of the studied materials at moderate amplitudes of the shock-wave effect agree with the known literature data, while at higher pressures the growth of spall strength is observed, which is an evidence of the material hardening. The results of the studies demonstrate that the dynamic strength of a substance depends on both the duration and the amplitude of the shock-wave impact on the target.

Cavitation erosion resistance of low temperature plasma nitrided martensitic stainless steel

The cavitation erosion resistance of non-nitrided and low plasma nitrided AISI 410 martensitic stainless steel was evaluated according to ASTM G32 standard. Plasma nitriding was carried out in a hot wall DC-pulsed plasma reactor at 400°C in a mixture of 75% of nitrogen and 25% of hydrogen during 20h. The ASTM A 743 grade CA6NM stainless steel was used for comparison purposes. The microstructure of the steels was characterized by optical and scanning electron microscopy, as well as by X-ray diffraction. Expanded martensite and iron nitrides were formed at the surface of the martensitic AISI 410 stainless steel. Curves of mass loss, erosion rate and roughness parameters were plotted as a function of exposure time. The 25μm thick nitride layer showed two distinct regions: a first 5μm thick layer just beneath the surface containing precipitated ε Fe3N nitrides and expanded martensite and the rest of the layer constituted solely by expanded martensite. Iron nitride precipitation drastically reduced the incubation period, allowing detachment of entire grains due to the impact of shock-waves over the surface. Despite this, after removal of the first 5μm thick layer, the cavitation erosion resistance improved significantly. The relationship between microstructure and time-variation curves and wear mechanisms are discussed.

Impact of low-energy extracorporeal shock wave on collagen deposition and transforming growth factor-β1 expression in excisional wound of diabetic rats

Objective To investigate the effect of low-energy extracorporeal shock wave (ESW)treatment on collagen deposition and transforming growth factor-β1 (TGF-β1) expression in excisional wound of diabetic rats,and the possible mechanism of ESW promoting wound healing.Methods Chronic diabetic wound models were made in 64 6-8-week-old male SD rats weighing (220 ±20) g,and randomly divided into the ESW treatment group and the diabetic control group.Normal wound models were made in 32 SD rats and were used as the normal control group.In ESW treatment group,wound was treated by ESW with 0.11 mJ/mm2,1.5 Hz and 500 pulses one day post-wounding.In diabetic control group and normal control group,wound was only given coupling fluid and received no ESW treatment.Wound closing rate was calculated at 3rd,7th,14th and 21st day after treatment.Wound specimens were harvested to observe histological changes,hydroxyproline contents,density of collagen fibers and TGF-β1 expression.Resuits At different time points after treatment,collagen deposition,the relative density of collagen and hydroxyproline content were decreased in the diabetic control group as compared with those in the normal control group (P ＜ 0.05).At the same time,TGF-β1 expression was significantly decreased in the diabetic control group (P ＜ 0.05).After ESW treatment,fibroblasts and granulation tissue formation were increased,and collagen fibers density and hydroxyproline content in the wound were also increased simultaneously (P ＜ 0.05),and there was no significant difference in collagen fibers density and hydroxyproline content between the ESW group and normal control group (P ＞0.05).In addition,TGF-β1 expression at different time points was increased (P ＜ 0.05) and began to decline at 14th day in the ESW treatment group as compared with that in the diabetic control group.Conclusion The reduced collagen deposition is a major contributor of impaired diabetic wound healing and ESW treatment may increase the expression of TGF-β1,fibroblast migration or proliferation,collagen formation and hydroxyproline content within the wound tissue,and thus accelerate granulation tissue formation and wound healing process. Key words: Diabetes ; Wound; Collagen ; Transforming growth factor-β1

Shock Waves Impacting Composite Material Plates: The Mutual Interaction

High-performance, fiber-reinforced polymer composites have been extensively used in structural applications in the last 30 years because of their light weight combined with high specific stiffness and strength at a rather low cost. The automotive industry has adopted these materials in new designs of lightweight vehicles. The mechanical response and characterization of such materials under transient dynamic loading caused with shock impact induced by blast is not well understood. Air blast is associated with a fast traveling shock front with high pressure across followed by a decrease in pressure behind due to expansion waves. The time scales associated with the shock front are typically 103 faster than those involved in the expansion waves. Impingement of blast waves on structures can cause a reflection of the wave off the surface of the structure followed by a substantial transient aerodynamic load, which can cause significant deformation and damage of the structure. These can alter the overpressure, which is built behind the reflected shock. In addition, a complex aeroelastic interaction between the blast wave and the structure develops that can induce reverberation within an enclosure, which can cause substantial overpressure through multiple reflections of the wave. Numerical simulations of such interactions are quite challenging. They usually require coupled solvers for the flow and the structure. The present contribution provides a physics-based analysis of the phenomena involved, a critical review of existing computational techniques together with some recent results involving face-on impact of shock waves on thin composite plates.

Macro-mechanical modeling of blast-wave mitigation in foams. Part II: reliability of pressure measurements

A phenomenological study of the process occurring when a plane shock wave reflected off an aqueous foam column filling the test section of a vertical shock tube has been undertaken. The experiments were conducted with initial shock wave Mach numbers in the range \(1.25\le {M}_\mathrm{s} \le 1.7\) and foam column heights in the range 100–450 mm. Miniature piezotrone circuit electronic pressure transducers were used to record the pressure histories upstream and alongside the foam column. The aim of these experiments was to find a simple way to eliminate a spatial averaging as an artifact of the pressure history recorded by the side-on transducer. For this purpose, we discuss first the common behaviors of the pressure traces in extended time scales. These observations evidently quantify the low frequency variations of the pressure field within the different flow domains of the shock tube. Thereafter, we focus on the fronts of the pressure signals, which, in turn, characterize the high-frequency response of the foam column to the shock wave impact. Since the front shape and the amplitude of the pressure signal most likely play a significant role in the foam destruction, phase changes and/or other physical factors, such as high capacity, viscosity, etc., the common practice of the data processing is revised and discussed in detail. Generally, side-on pressure measurements must be used with great caution when performed in wet aqueous foams, because the low sound speed is especially prone to this effect. Since the spatial averaged recorded pressure signals do not reproduce well the real behaviors of the pressure rise, the recorded shape of the shock wave front in the foam appears much thicker. It is also found that when a thin liquid film wet the sensing membrane, the transducer sensitivity was changed. As a result, the pressure recorded in the foam could exceed the real amplitude of the post-shock wave flow. A simple procedure, which allows correcting this imperfection, is discussed in detail.

Deterioration of FRC Plate due to Explosion and Change of Temperature

Recently it was shown that the temperature plays very important role in coupling with the impact of shock wave caused by explosion in a free space. The deterioration of fiber reinforced concrete structures, FRC, at the face to which the main impact of the coupled load is directed is not easy to describe. In couple of previous papers of the author the problem was solved under condition that the structure behaves elastically. It appeared that a numerical tool known as free hexagon method, which is based on soft contact problem in combination with boundary elements, seems a powerful approach solving any disconnecting media. The soft contact is identified by nonlinear spring rules. Similar idea is used in the suggested paper for solving the coupled problem envisaged, but the mesh of free hexagons is split into the air and the structure. If the impact of explosion and the subsequent shock wave cause is viewed separately from the changes in material due to temperature a very fast changes in stresses and movements in material are observed in the first case while the changes due to temperature develop much slower. On the other hand in combination of both influences the temperature increase the activity inside of structures considerably. In the paper the theory is briefly described and selected examples illustrate the mobility of the application of the method to a problem of FRC plate.