Impact Of Shock Wave Research Articles

Shear Thickening Fluids, Nano-Polymer Materials and their Application Methods for Textile Substrates

Shear Thickening Fluid (STF) is a highly preferred phase change material that helps in absorbing high impact shock waves and provides excellent protective properties when used along with Kevlar fabric. nanomaterials also offer superior functionality helping in creating many useful, smart and innovative textile fabrics. This research work aims to analyze the synthesis steps, properties and application methods of nanomaterials made from different chemical synthesis methods. The effect of many technical factors and process control parameters is also laid out and found to be important contributors for creating unique fabric property. This analysis provides a guideline to effectively and efficiently use the nanomaterials in the right way and apply the functional nanomaterials using suitable technology for coating which can enrich the functional property of the substrate.

Laser-Shock-Driven In Situ Evolution of Atomic Defect and Piezoelectricity in Graphitic Carbon Nitride for the Ionization in Mass Spectrometry.

Nanostructures─coupled with mass spectrometry─have been intensively investigated to improve the detection sensitivity and reproducibility of small biomolecules in laser desorption/ionization mass spectrometry (LDI-MS). However, the impact of laser-induced shock wave on the ionization of the nanostructures has rarely been reported. Herein, we systematically elucidate the laser shock wave effect on the ionization in terms of the in situ development of atomic defects and piezoelectricity in two-dimensional graphitic carbon nitride nanosheets (g-C3N4 NS) by short laser pulses. The mass analysis results of immunosuppressive drugs verify the enhanced LDI-MS performance, structurally originating from anisotropic lattice distortions in g-C3N4 NS, i.e., in-plane extension (contraction) and out-of-plane contraction (extension) that modulate the charge carrier motion. Along with the experimental investigations, density functional theory calculations on Mulliken charges and dipole moments demonstrate the contribution of defect and piezoelectricity to the ionization. The results of this study provide a mechanistic understanding of the underlying ionization processes, which is crucial for revealing the full potential of laser shock waves in LDI-MS.

Numerical Investigation on Supersonic Film Cooling Performance with Discrete Film Holes

The effect of the discrete film cooling hole type on flow characteristics and the cooling performance of supersonic film cooling are numerically studied on a flat plate. Three film hole types (cylindrical hole, merged hole, and sister hole) are evaluated. Numerical simulation is conducted under a constant mainstream Mach number and six coolant Mach numbers ranging from . The three-dimensional effects of shock impingement on the flow characteristics and cooling performance are analyzed. The flow features (especially the interaction between the jet flow and the mainstream) are illustrated. The results show that the supersonic film cooling performance is heavily affected by many factors: the shear layer developed from the detached boundary layer, the boundary-layer separation downstream of the film hole, the jet liftoff phenomenon, the kidney vortex, and the oblique shock wave impingement. Those factors, except for the shock wave impingement, are heavily affected by the discrete film hole types and coolant Mach numbers. The shock impingement is not conducive to the lateral expansion of the cooling film. There is an optimal coolant Mach number for the best film cooling effectiveness under three film hole types, and the sister hole yields the best cooling performance.

"MODEL ACHIEVEMENT FOR IGNITION AND DEVELOPMENT OF STOCHASTIC DISCHARGE CHANNELS IN CONCRETE AND REINFORCED CONCRETE TAKING INTO ACCOUNT THE PROPERTIES OF THE MEDIUM AND THE GEOMETRY OF THE REINFORCING FRAME"

"The article develops a generalized model of electrodischarge action on concrete, which allows consistently describing phases of electro-explosion in condensed media: initiation and development of discharge channels, expansion, generation of shock waves, interaction of waves with the material being processed, deformation and destruction of solid materials. The model is based on a stochastic deterministic approach to the development of instability. processes associated with the distribution of the electric field, when mechanical stresses break. The flow of the process is considered deterministically on the basis of nonlinear integro-differential equations, local processes leading to the growth of the channel and cracks - stochastically. Equations describing the nature of the discharge development, the change of the channel resistance and its expansion are concordantly solved with the transition equations in the scheme of the real pulse generator. Expansion of the channel in the liquid is based on the law of conservation of energy, mass, pulse, equations of wave dynamics and allows to calculate the temporal and amplitude impact of shock waves from the channel on the barriers. The process of electrical breakdown of condensed dielectrics occurs with the development of a stochastically discharge structure, mainly determined by the emergence of highly conductive plasma channels. The development of the channel structure begins in the area of maximum field tension. In this case, the processes of phase transitions of a material directly determine the quantitative and qualitative processes of image of channels. As part of the study of the model, an analysis of the influence of the movement of electro-discharges on the redistribution of the electrostatic field, conditions leading to the direct formation of discharge channels, fracture formation and complete deformation was conducted. Keywords: model, electro-discharge device, stochastic-deterministic approach, electric field, mechanical voltage, shock wave, channel resistance, dielectric, pulse generator, differential equations."

Low-velocity impact behavior of two-way RC slab strengthening with carbon TRM strips

Sudden dynamic impact loading on reinforced concrete (RC) slabs due to reasons such as the impact of debris due to landslide or rock fall, the impact of drifting objects due to effects such as flood or tsunami, the impact of vehicles on highway or seaway bridges, the impact of air shock waves due to explosions inside or outside of structures may lead damage and collapses. This study is aimed to examine the behavior of RC slabs reinforced with Textile Reinforced Mortar (TRM) strips, which have been used in reinforcement applications for the last ten years, under the effect of sudden dynamic impact loading. The variables examined in the experimental study are the TRM strip width, the placement of the strips, and whether the anchors are present on the strips or not. The acceleration-time, displacement–time, strain–time over the strips, and applied impact loading-time distributions are measured and interpreted under the effect of impact loading with a constant energy level applied by the drop-weight system. In addition, numerical analysis of the slabs is done with Ls-Dyna software, compared with the experimental results, and examines how successful the analysis results are. The reinforcement technique applied with TRM strips developed within this study's scope significantly increased RC slabs' performance under impact loading. The TRM strips used for strengthening in both directions were the variable that had the most positive effect on impact behavior. Increasing the strip width and anchoring followed the use of double directional strips in improving performance under the impact loading.

Battery-Aware Cooperative Merging Strategy of Connected Electric Vehicles Based on Reinforcement Learning With Hindsight Experience Replay

Cooperative control of connected and automated electric vehicles (CAEVs) offers a great potential for a safe, high-efficient, sustainable transportation system. Among them, coordinated on-ramp merging based on an on-ramp merging vehicle and a mainline facilitating is a hot spot to lighten the impact of shockwave on highway junctions. Reinforcement learning (RL) is a promising solution to address this problem for its strong adaptiveness and self-learning ability. The existing methods are dedicatedly designed to circumvent the sparse reward problem of long-term merging safety but restrict the optimization space and neglect individual costs, especially irreversible loss, such as battery aging. In this article, a hindsight experience replay RL coordinated freeway on-ramp merging frame is proposed to face the sparse reward problem in ramp merging problem and, meanwhile, co-optimize traffic efficiency, energy-saving, and battery health performance. Compared with the existing optimization-based strategy, it fundamentally avoids abundant expert knowledge and elaborate design for reward shaping and model construction while ensuring the nature of merging tasks without excessive simplification. Numerical experiments are conducted to verify the optimality, adaptability, and self-learning ability of the proposed strategy. With comparison experiment, the proposed strategy surpasses state-of-the-art RL methods more than 13% in overall index throughput with 12% energy consumption while easing individual battery aging during the merging process.

Image-based characterization of the bubbly shock wave generation and evolution in aviation fuel cavitation

An experimental investigation of cavitation in aviation fuel (JP-8 and JP-5) in a converging-diverging nozzle geometry is presented. A novel enhanced gradient shadowgraphy image processing technique is developed and employed in order to characterize the fundamental processes involved in unsteady bubbly shock wave generation and evolution, both with and without micro-air bubble injection at the inlet. We clarify the sequence of unsteady processes at play in aviation fuel cavitation and provide new perspectives regarding the damaging impact of shock waves that will lead to improved design of fuel system components.

Comparative Study of Structural and Mechanical Properties of as Deposited and Shock Wave Exposed NiW Nano Structured Thin Films

The current work describes the effect of shock wave exposure on electroplated NiW thin films. NiW thin films were deposited through electrodeposition process by varying the bath temperatures (35°C and 70°C) at constant current density of 1A/dm2. The deposited NiW thin films were exposed to shock waves with varying Mach numbers of 1.13 and 2.33 using an in-house shock wave tube facility. The as-deposited and shock wave-exposed NiW thin films were characterized by XRD, FESEM, EDS, and EIS to reveal its structural and mechanical properties. The XRD results disclose the stable cubic structural phase of as deposited and shock wave exposed NiW thin films with average crystallite size varying between 5 nm to 17nm. The elemental composition of as-deposited and shock-wave exposed films are similar as confirmed in the EDS analysis. This henceforth represents the stability of nanostructured NiW film in terms of compositional and structural aspect. Morphological analysis through FESEM shows that the exposed thin film is defect free due to the impact of shock waves. Furthermore, corrosion resistance is observed to enhance ten times in shock-wave exposed thin film than as-deposited thin film for higher mach number (Pressure ~63 bar). Similarly, corrosion resistance for low mach number (pressure ~13 bar) increases by three times of as deposited film according to the EIS analysis. Therefore, the structural, morphological and corrosion properties were enhanced upon surface treatment by shock wave exposure. NiW thin films with enhanced mechanical properties such as low corrosion rate, high corrosion resistance is used in various industrial applications like defense applications, aircraft, and marine applications.

Experimental Investigation Of Shock Induced Panel Flutter With Simultaneous Use Of DIC And PIV

In this experimental study, both classical and shock induced supersonic panel flutter are investigated at a freestream Mach number of 2, using a combination of planar particle image velocimetry (PIV) and stereographic digital image correlation (DIC) to obtain simultaneous full-field structural displacement and flow velocity measurements. Highspeed cameras are employed to obtain a time-resolved description of the panel motion and of the flow dynamics. In order to prevent interference between the PIV and DIC systems, an optical isolation is implemented using fluorescent paint, dedicated light sources, and camera lens filters. For the shock induced case, the effect of the panel motion on the SWBLI behavior is assessed, by comparing it with the SWBLI on a rigid wall. The results show that panel oscillations occur with an amplitude of ten times the panel thickness. The dominant frequencies observed in the panel oscillation (424 Hz and 1354 Hz) match the main spectral content of the reflected shockwave position. In absence of shock impingement, the oscillation amplitude is on the order of the panel thickness, while the dominant frequency contribution is at 730 Hz. The fluid-structure coupling is studied by identifying the flow regions of maximum correlation between the panel displacement and the flow velocity fluctuations. In presence of shock impingement the results obtained proved that the inviscid flow region upstream of the SWBLI is perfectly in phase with the panel oscillation, while the downstream region has a delay of one quarter of the flutter cycle. Instead, no delay is observed for the configuration in absence of shockwave impingement.

Compression response and shock-wave behavior of liquid nitrogen caused by energy injection in an enclosed pipeline

In a cryogenic liquid medium, shock waves will be formed by the expansion of compressed gas that has been vaporized due to the injection of a large amount of energy. This may severely threaten the reliability of high-Tc superconducting (HTS) apparatus. Several studies have documented the destructive forces of evaporating nitrogen produced by arc energy. However, the properties of and propagation mechanisms relating to pressure waves in liquid nitrogen have yet to be understood. The aim of this study was to clarify the evolution of pressure waves within an enclosed pipeline and reveal the effects of several factors such as the pipe size and the injected energy on the shock-wave impact using explosion dynamics simulations. The results provide evidence for the strengthening of shock waves due to multiple reflection and superposition. In addition, analysis of the pressure impulse and effective strain reveals that, in the case of moderate injected energy, the overall shape of the inside wall of the pipe will remain unchanged except at the points closest to the explosion center; in contrast, the ends of the pipeline may suffer from more severe deformation. Finally, the calculations suggest that the shock-wave impact increases almost linearly with the injected energy, and in logarithmic coordinates, the pressure is inversely proportional to the explosion distance. These findings provide a better understanding of the characteristics and propagation patterns of shock waves in liquid nitrogen, and they lay a foundation for evaluating the safety of HTS cables and energy pipelines.

Compressibility effect on interaction of shock wave and turbulent boundary layer

The compressibility effect when an oblique shock wave impinges on a turbulent boundary layer was analyzed with a direct numerical simulation using Helmholtz decomposition. The turbulent intensity near the impinging region is significantly enhanced by the interaction of the shock wave and boundary layer. In particular, the interaction behavior can enhance the dilatational components of the Reynolds stress and velocity fluctuations. This also enhances the negative correlation between the dilatational components of streamwise and normal velocity fluctuations. The dilatation fluctuation in the impinging region increases significantly. Moreover, in the impinging region, the dilatational components of the production term and transport term contribute to the production and transport terms of the kinetic energy equation mainly in the vicinity of the interface. This simulation shows that the interaction behavior of an oblique shock wave and turbulent boundary layer can enhance flow compressibility significantly. In the interaction region, the turbulent intensity of the flow field is stronger than those upstream and downstream. This study provides a theoretical basis for the improvement of other simulation methods and turbulence modeling for the interaction of an oblique shock wave and turbulent boundary layer.

Shock-wave impact on the knee joint affected with osteoarthritis and after arthroplasty

Degenerative diseases significantly reduce the quality of human life. Non-invasive treatments are used in the initial stages of osteoarthritis (OA). Total knee arthroplasty is used in the late stages of osteoarthritis of the knee joint. Non-invasive methods based on mechanical action are also used for the rehabilitation of a patient after arthroplasty. This paper presents numerical models of the knee joint with degenerative OA changes and arthroplasty. Using these models, a computational study was made of the influence of the intensity of shock-wave exposure on the conditioning for the regeneration of bone and cartilage tissues. Based on the modeling results, it was found that in the knee joint with degenerative OA changes, conditions for the regeneration of cartilage and meniscus tissues were fulfilled under medium and high-intensity loading. Under high-intensity loading (up to 0.9 mJ/mm2), the stress level was significantly below the ultimate value required for fracture. At knee arthroplasty, the conditions for bone tissue regeneration around the tibia component are fulfilled only under high-intensity loading.

Death of the Caspian seals on the Dagestan coast of the Caspian Sea in the autumn of 2020 and its possible reasons

The aim of this research was to assess the scale and determine the possible reasons of the death of Caspian seals (Pusa caspica), that were washed up by a storm on the coast of the Republic of Dagestan in early December 2020. The corpses of seals were found on the Dagestan coast from the mouth of the Terek River to the southern outskirts of Derbent, in total about 205 km long. The main methods of collecting material were: accounting of dead seals in open (not overgrown with vegetation) coastal areas, measurements and pathoanatomic autopsies of corpses, sampling of internal organs and tissues of animals for histological, virological, helminthological and toxicological studies. Simultaneously with the onshore work, observations of seals and registration of hydro- meteorological parameters in the coastal waters of the Republic of Dagestan were carried out by two research vessels of the Caspian branch of the Federal Research Institute for Fishery and Oceanography («KaspNIRH»): «Caspian Explorer» and «Hydrobiologist». As a result, 12 coastal sites with a total length of 49.2 km were surveyed, where 313 corpses of dead seals were registered; the average density was 12.27 ± 2.16 specimens/km. The total number of dead seals in December 2020 was estimated at 2,515 ± 443 individuals. Adult females predominated among the dead animals, most of which were pregnant. The corpses showed no signs of infectious diseases or exhaustion. Judging by their condition, the death of animals occurred during the first two decades of November, at some distance from the shore. Conclusion: Basing on the data collected, infectious diseases, helminthiasis, intoxication, accident by catch in the fishing gears, and the impact of an underwater shock wave were excluded from the possible reasons of the death of seals. Acute asphyxia as a result of local release of natural gas, which could form above the sea surface a polluted lens of air unsuitable for breathing, was recognized as the most likely cause of the seals death.

New Results Regarding the Cavitation Destruction Behavior of Heat-Treated CuZn39Pb3 Brass with Different Parameters

Among other parts made of brass there are also the blades and the rotors of the hydraulic machines, respectively ship propellers, which during operation are degraded by cavitation erosion. As a result, most of the researches, including the most recent ones, are focused on the morphological analysis of structures eroded under the impact of micro-jets and shock waves, produced by cavitation hydrodynamics. The goal is to create new materials, but also to use new treatment technologies to increase cavitation resistance. As the literature is quite poor in studies related to the materials resistance to cavitation erosion, respectively treatments and technological procedures of it’s improvement, this paper presents the research results on the behavior of vibration cavitation erosion, carried out on three sets of CuZn39Pb3 brass samples, subjected to volumetric heat treatments of hardening for putting in solution at 800°C, followed by tempering at 250°C, 400°C and 600°C. The characterization of the behavior and the cavitation resistance of the structures resulting from the applied heat treatments is performed based on macroscopic images, taken at different representative periods, SEM images at the end of the test duration and values ​​of specific parameters recommended by ASTM G32-2016. The analysis highlights the differences caused by the change in structure by varying the temperature, but also the hardness of the surface exposed to the cavity. Thus, of the three treatments, it is found that the best resistance to cavitation is conferred by the structure resulting from hardening at 800°C, with tempering at 250°C.

Wall heat flux in a supersonic shock wave/turbulent boundary layer interaction

The characteristics of wall heat flux (WHF) beneath a supersonic turbulent boundary layer interacting with an impinging shock wave with a 33.2° angle at Mach 2.25 are analyzed using direct numerical simulation. It is found that the QP85 scaling, defined as the ratio of the mean WHF and wall pressure, changes across the interaction. The probability density function of the WHF fluctuations normalized by the local root-mean-squared value is similar to that of wall shear stress. Comparing the WHF and wall pressure spectra shows that the low-frequency shock unsteadiness exhibits little influence on the spectrum. The space–time correlation of the fluctuating WHF reveals that both the streamwise correlation length scale and the convection velocity experience a sharp decrease in the separation region and subsequent recovery in the downstream region. Moreover, the mean WHF in an incident shock interaction is decomposed for the first time. An analysis of the velocity and temperature fluctuations based on bidimensional empirical mode decomposition is performed to evaluate the contribution of turbulent structures with specific spanwise length scales to the mean WHF generation. The decomposed results indicate that the contribution associated with the large-scale structures in the outer region is greatly amplified by the shock interaction and has the leading role in the generation downstream of the interaction.

Film Cooling Method In Liquid Rocket Engine.

Design Criteria, Experimental Studies of Supersonic Shock Wave Interaction with Film Cooling, and High-Pressure Subscale Combustion Chamber of Film Cooling Liquid-Propellant Rocket Engines are all covered in this review study. Using earth-storable, space-storable, and cryogenic propellant combinations, the study establishes the applicability of film cooling to rocket engines in the high thrust range. The study's findings are given in this publication. Additionally, data from studies mixing different types of propellant were used to evaluate the analytical model's accuracy. Tests employing supersonic film cooling were done in the wind tunnel to investigate the impact of external shock waves on supersonic film cooling. The coolant injection was carried out at a supersonic speed. Furthermore, we discuss the important factors that impact film cooling, such as the efficacy of the injected film and the reduction in wall temperature. A high-pressure subscale combustion chamber was used in conjunction with a combination of cryogenic propellants to conduct the experimental investigation. It is critical to consider the increase in the coefficient of heat transfer.

Assessment of sustainability on structure-optical properties of prismatic face ADP crystal at dynamic shocked conditions

In the present research article, we have performed an extensive experimental investigation on the structural and linear optical properties of the prismatic face ammonium dihydrogen phosphate (ADP) crystals under the impact of shock waves of various counts such that the crystals have been analyzed by X-ray diffraction, Raman spectroscopic, Ultra-violet Visible spectroscopic and optical microscopic techniques. XRD and Raman results clearly show that the shocked ADP crystals have undergone significant changes such as lattice deformations, lattice disorders giving rise to the structural disorders and significant reduction in optical transmittance with respect to the number of shock pulses. Optical microscopic images also authenticate the formation of defective surface morphology at shocked conditions. Furthermore, we have made the comparison of the optical transmission of the prismatic face with the previously published pyramidal face ADP crystal with respect to the number of shock pulses.

Sustainable structural, morphological and magnetic properties of MgFe2O4 nanoparticles under dynamic shock wave exposure

In this article, the authors have explored the changes caused in structural, morphological and magnetic properties of magnesium ferrite nanoparticles (MgFe2O4 NPs) under dynamic shock wave exposure situations. Interestingly, the observed XRD and VSM results reveal that the MgFe2O4 NPs have outstanding crystallographic and magnetic phase stability against the impact of shock waves and found that the title NPs are having higher shock resistance than other potential materials such as TiO2, Co3O4 and ZnFe2O4 NPs.

Experience of applying the shock wave impact method for the bottomhole zone

Improving the processes of exploration and development of fields, as well as increasing the productivity of oil reserves using physicochemical methods are one of the main tasks in stabilizing oil recovery and increasing the oil recovery factor. The most rational method used for hard-to-recover reserves is the shock-wave impact technology. This method can stimulate the release of energy from anomalously stressed zones and intensify the influx of hydrocarbons from deep layers of the Earth along the tectonic faults and sub-vertical inversion ring structures. The article presents the results of a study of the shock-wave impact on production wells of the Sabanchinskoye field and discusses factors that reduce the profitability of this technology.

RETRACTED: Impact of shock waves on the physical and chemical properties of aligned zinc oxide structures grown over metal-sheets

Zinc oxide (ZnO) nanorods were developed on stainless steel (SS) sheets as well as glass substrates in two steps by adopting well-established two different chemical methods namely, spray pyrolysis and chemical bath deposition techniques. Then, the structures were exposed to dynamically generated shock waves in a home-built shock tunnel. All the as-grown and shock waves exposed structures were characterized with advanced analytical techniques. Surface morphology and structural studies reveal that the as-grown nanostructured films over the both SS and glass substrates possess nanorods-like surface morphology; however, they exhibited (101) and (001) orientations as predominant orientations, respectively. From micro Raman analysis, it is noticed that the nanorod structures grown on both surfaces have good phase purity and crystalline quality. On the other hand, the cathodoluminescence studies show that these hydrothermally grown ZnO nanorods possess a large number of native defects. Finally, the ZnO nanorods exposed to shock waves generated with a temperature and pressure of ca. ∼20,000 K and ∼6 MPa for a short duration of 2–3 ms exhibited superb sustainability in terms of surface morphology as well as crystalline quality, which is mainly attributed to the slantly overlapped morphology as well as the high melting temperature of ZnO nanorods.