Artykuły w czasopismach: „Water Shock Tube”

1

Hou, Zi-wei, Ning Li, Xiao-long Huang, Can Li, Yang Kang i Chun-sheng Weng. "Three-dimensional numerical simulation on near-field pressure evolution of dual-tube underwater detonation". Physics of Fluids 34, nr 3 (marzec 2022): 033304. http://dx.doi.org/10.1063/5.0086527.

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The detonation-powered underwater engine, with the advantages of high specific impulse, high speed, and simple structure, has very broad application prospects in the field of underwater propulsion, and dual-tube combination is an effective means to improve its propulsion performance. In this work, near-field pressure evolution of shock waves and high-pressure zones between two detonation tubes is numerically studied. The two-fluid model and three-dimensional conservation element and solution element method are adopted to reveal the formation, intersection, and interaction of shock waves. Detonation waves generated by two detonation tubes decouple into shock waves after penetrating into water and form a high-pressure zone near each tube exit. The two leading shock waves intersect with each other in the propagation, creating the second high-pressure zone between two tubes. Then, a propagating forward merged new shock wave covers the two original wave-fronts and maintains higher pressure. Pressure evolution under different tube intervals, ignition delays, and filling conditions is also presented to discuss their influence on the performance of dual-tube detonation. The intensity and directivity of shock waves are found to be sensitive to these factors, complexly affecting the thrust components, which provides a depth understanding of dual-tube combination in the application.

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Ji, H., M. Mustafa, H. Khawaja, B. Ewan i M. Moatamedi. "Design of water shock tube for testing shell materials". World Journal of Engineering 11, nr 1 (1.03.2014): 55–60. http://dx.doi.org/10.1260/1708-5284.11.1.55.

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This paper presents design considerations for a shock tube experimental rig used to investigate the dynamic failure mechanisms of shell geometries subjected to water shock impact loading. In such setup, it is desirable that the drive pressure used within the tube can provide a wide range of impulsive loads on the test structures and some flexibility can be achieved on the applied pulse durations. With this aim a review of various existing shock tube experimental setup is presented and choices are made based on scientific merits. Finally design parameters are drawn for right set of conditions required for the experiments.

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Vukovic, Gordana, i Michael L. Corradini. "Liquid-Metal/Water Interactions in a Shock Tube". Nuclear Technology 115, nr 1 (lipiec 1996): 46–60. http://dx.doi.org/10.13182/nt96-a35274.

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Chambers, G., H. Sandusky, F. Zerilli, K. Rye, R. Tussing i Jerry Forbes. "Pressure Measurements on a Deforming Surface in Response to an Underwater Explosion in a Water-Filled Aluminum Tube". Shock and Vibration 8, nr 1 (2001): 1–7. http://dx.doi.org/10.1155/2001/146373.

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Experiments have been conducted to benchmark DYSMAS computer code calculations for the dynamic interaction of water with cylindrical structures. Small explosive charges were suspended using hypodermic needle tubing inside Al tubes filled with distilled water. Pressures were measured during shock loading by tourmaline crystal, carbon resistor and ytterbium foil gages bonded to the tube using a variety of adhesives. Comparable calculated and measured pressures were obtained for the explosive charges used, with some gages surviving long enough to record results after cavitation with the tube wall.

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ANDO, KEITA, T. SANADA, K. INABA, J. S. DAMAZO, J. E. SHEPHERD, T. COLONIUS i C. E. BRENNEN. "Shock propagation through a bubbly liquid in a deformable tube". Journal of Fluid Mechanics 671 (15.02.2011): 339–63. http://dx.doi.org/10.1017/s0022112010005707.

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Shock propagation through a bubbly liquid contained in a deformable tube is considered. Quasi-one-dimensional mixture-averaged flow equations that include fluid–structure interaction are formulated. The steady shock relations are derived and the nonlinear effect due to the gas-phase compressibility is examined. Experiments are conducted in which a free-falling steel projectile impacts the top of an air/water mixture in a polycarbonate tube, and stress waves in the tube material and pressure on the tube wall are measured. The experimental data indicate that the linear theory is incapable of properly predicting the propagation speeds of finite-amplitude waves in a mixture-filled tube; the shock theory is found to more accurately estimate the measured wave speeds.

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Buren, A. L. Van, i L. D. Luker. "Nonlinear wave propagation in a water‐filled, conical shock tube". Journal of the Acoustical Society of America 95, nr 5 (maj 1994): 2864. http://dx.doi.org/10.1121/1.409504.

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Ke, Hanbing, Qi Xiao, Chengyi Long, Jialun Liu, Leitai Shi i Linghong Tang. "A Modified Calculation Method for a Centered Water Nozzle Steam–Water Injector". Energies 15, nr 23 (2.12.2022): 9159. http://dx.doi.org/10.3390/en15239159.

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A centered water nozzle steam–water injector is driven by cold water to pump steam at a low pressure and to produce a high outlet water pressure. It can be used as a safety pump in a light water reactor to inject cooling water into the reactor core with no power supply in case of an accident. In this study, a modified calculation method for a centered water nozzle steam–water injector is proposed and verified by experimental data in the literature. The calculation method consists of a water nozzle model, a steam nozzle model, a mixing section model, and a shock wave model. Comparisons between the calculated results and the experimental results under different inlet steam pressures, inlet water pressures, and back pressures are conducted, and the calculated results show good agreement with the experimental results. The calculated results with different back pressures show that no shock wave occurs in the mixing section when the back pressure is small, but with the back pressure increasing, the pressure undergoes a dramatic increase in the throat tube, and the shock wave position moves towards the inlet of the mixing section. Due to the complexity of shock wave characteristics, it is necessary to conduct a more in-depth study of shock wave characteristics in the mixing section to determine more detailed boundary conditions for shock wave generation.

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Sivakumar, A., i S. A. Martin Britto Dhas. "Shock-wave-induced nucleation leading to crystallization in water". Journal of Applied Crystallography 52, nr 5 (29.08.2019): 1016–21. http://dx.doi.org/10.1107/s1600576719009488.

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It is well known that super-cooled materials can be crystallized under the application of shock waves. This is the first report describing crystallization from unsaturated liquids. Shock-wave-induced crystallization of salts from environmental ground and sea water samples is explored. A table-top pressure-driven shock tube is utilized so as to produce the required shock waves of Mach numbers 1.1, 1.2, 1.4, 2.2 and 4.7. The demonstration comprises a train of acoustic shock pulses applied to the water samples. As a consequence of the impact of the shock waves, the colourless water becomes turbid, following which tiny crystallites are precipitated at the bottom of the vessel after a few minutes. The obtained precipitate is subjected to powder X-ray diffraction and energy-dispersive X-ray spectroscopy analysis to confirm the nature of the settled particles and the elements present in them, respectively. From the observed results, it is concluded that shock-wave-induced crystallization in water provides an alternative method for removing dissolved salts from both ground and sea water samples.

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Neaves, Michael Dean, i Jack R. Edwards. "All-Speed Time-Accurate Underwater Projectile Calculations Using a Preconditioning Algorithm". Journal of Fluids Engineering 128, nr 2 (30.08.2005): 284–96. http://dx.doi.org/10.1115/1.2169816.

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An algorithm based on the combination of time-derivative preconditioning strategies with low-diffusion upwinding methods is developed and applied to multiphase, compressible flows characteristic of underwater projectile motion. Multiphase compressible flows are assumed to be in kinematic and thermodynamic equilibrium and are modeled using a homogeneous mixture formulation. Compressibility effects in liquid-phase water are modeled using a temperature-adjusted Tait equation, and gaseous phases (water vapor and air) are treated as an ideal gas. The algorithm is applied to subsonic and supersonic projectiles in water, general multiphase shock tubes, and a high-speed water entry problem. Low-speed solutions are presented and compared to experimental results for validation. Solutions for high-subsonic and transonic projectile flows are compared to experimental imaging results and theoretical results. Results are also presented for several multiphase shock tube calculations. Finally, calculations are presented for a high-speed axisymmetric supercavitating projectile during the important water entry phase of flight.

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Igra, D., i K. Takayama. "Experimental Investigation of Two Cylindrical Water Columns Subjected to Planar Shock Wave Loading". Journal of Fluids Engineering 125, nr 2 (1.03.2003): 325–31. http://dx.doi.org/10.1115/1.1538628.

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Two water columns with identical initial diameters of 4.8 mm were placed 30 mm apart inside a shock tube test section and were loaded by a shock wave of Mach number 1.47 in atmospheric air. The Weber and Reynolds numbers corresponding to these flow conditions are 6900 and 112,000, respectively. Double-exposure holographic interferometry was used to visualize the shock/water columns interaction. The process of the water columns deformation, displacement, and acceleration was well visualized and hence the drag coefficient of shock loaded water columns was evaluated. The front water column behaved virtually the same as a single water column under the same flow conditions. However, the displacement and acceleration of the rear water column was less significant than that of the front one. Hence, its drag coefficient is less. These results show that the front water column has affected the flow field around the rear water column.

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Deshpande, V. S., A. Heaver i N. A. Fleck. "An underwater shock simulator". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 462, nr 2067 (17.01.2006): 1021–41. http://dx.doi.org/10.1098/rspa.2005.1604.

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An underwater shock simulator has been developed for the underwater shock loading of materials and test structures within the laboratory. The tube is struck at one end by a steel projectile, with the test structure placed at the opposite end of the tube. Realistic exponentially decaying pressure pulses are generated in the water with peak pressures in the range 15–70 MPa and decay times ranging from 0.1 to 1.5 ms. The peak pressure and the pulse duration are independently adjusted by varying the projectile velocity and mass, respectively. The underwater shock simulator is used to investigate the one-dimensional fluid–structure interaction of sandwich plates with steel face sheets and an aluminium foam core. The degree of core compression is measured as a function of both the underwater shock impulse and the Taylor fluid–structure interaction parameter. Fully coupled finite element simulations agree well with the measurements while decoupling the fluid–structure interaction phase from the core compression phase within the finite element analysis leads to an under-prediction of the degree of core compression.

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Chen, Chen-Yuan, Ruo-Ling Dong, Hong-Hui Shi i Yi Liu. "Instability and Atomization of Liquid Cylinders after Shock Wave’s Impacting". Applied Sciences 12, nr 24 (8.12.2022): 12597. http://dx.doi.org/10.3390/app122412597.

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This paper describes an experimental study on the instability and atomization of liquid cylinders after the impact of shock waves. Single row water column, in-line double rows water columns and alongside triple rows water columns were evaluated in a horizontal shock tube. The diameter of water column and the Mach number in the experiments were 2.0–4.14 mm and 1.10–1.25, respectively. The global instability along the axial direction of water cylinders was focused. Using a high-speed camera, the developments of spike height, bubble depth and turbulent mixing zone, width were measured. Some comparison was also made between the present experimental results and the existing theoretical model.

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SHI, Hong-Hui, Xiao-Liang WANG, Motoyuki ITOH i Masami KISHIMOTO. "Acceleration of Water Column and Generation of Large Flow Rate Water Spray by Shock Tube." JSME International Journal Series B 44, nr 4 (2001): 543–51. http://dx.doi.org/10.1299/jsmeb.44.543.

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Peters, F. "Condensation of supersaturated water vapor at low temperatures in a shock tube". Journal of Physical Chemistry 91, nr 10 (maj 1987): 2487–89. http://dx.doi.org/10.1021/j100294a009.

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Maerefat, M., T. Akamatsu i S. Fujikawa. "Non-equilibrium condensation of water and carbontetrachloride vapour in a shock-tube". Experiments in Fluids 9, nr 6 (wrzesień 1990): 345–51. http://dx.doi.org/10.1007/bf00188765.

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Megli, ThomasW, Herman Krier i RodneyL Burton. "Shock tube ignition of AL/MG alloys in water vapor and argon". Experimental Thermal and Fluid Science 7, nr 2 (sierpień 1993): 154. http://dx.doi.org/10.1016/0894-1777(93)90219-9.

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Zhang, Yu Peng, Shu Zhong Wang, Ze Feng Jing, Ming Ming Lv i Xiang Rong Luo. "Design and Simulation of Supersonic Swirling Separator". Advanced Materials Research 1008-1009 (sierpień 2014): 1148–53. http://dx.doi.org/10.4028/www.scientific.net/amr.1008-1009.1148.

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Supersonic swirling separator has been developed for natural gas dehydration in recent years. Compared to Twister-I supersonic swirling separator, Twister-II type overcomes the disadvantage of uncontrolled shock and the steady swirling flow field contributes to high efficiency of gas-liquid separation. The design method is discussed. For the Laval nozzle, the contraction section is designed by double cubic curve method, while the method for expansion section is tapered tube method the same as the divergent tube, throat is smooth circular arc; the length of straight swirling pipe section for separation is 3-8 times of the diameter. The paper simulates the applicability of the supersonic swirling separator by Fluent. Studies have shown that the lower environmental temperature, the lower the outlet temperature, the easier water to cool, and the higher the separation efficiency. If the volume flow rate rises, the inlet velocity and the mass flow rate can be effectively improved. We can control the shock location by adjusting the pressure at the outlet of divergent pipe. The shock appears at the inlet in the working condition designed. When the outlet pressure is lower, the shock occurs in divergent tube; on the opposite, it moves forward. Beyond a certain degree, shock occurs at the Laval nozzle, the device fails to work.

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Wan, Q., H. Jeon, R. Deiterding i V. Eliasson. "Numerical and experimental investigation of oblique shock wave reflection off a water wedge". Journal of Fluid Mechanics 826 (10.08.2017): 732–58. http://dx.doi.org/10.1017/jfm.2017.452.

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Shock wave interaction with solid wedges has been an area of much research in past decades, but so far very few results have been obtained for shock wave reflection off liquid wedges. In this study, numerical simulations are performed using the inviscid Euler equations and the stiffened gas equation of state to study the transition angles, reflection patterns and triple point trajectory angles of shock reflection off solid and water wedges. Experiments using an inclined shock tube are also performed and schlieren photography results are compared to simulations. Results show that the transition angles for the water wedge cases are within 5.3 % and 9.2 %, for simulations and experiments respectively, compared to results obtained with the theoretical detachment criterion for solid surfaces. Triple point trajectory angles are measured and compared with analytic solutions, agreement within $1.3^{\circ }$ is shown for the water wedge cases. The transmitted wave in the water observed in the simulation is quantitatively studied, and two different scenarios are found. For low incident shock Mach numbers, $M_{s}=1.2$ and 2, no shock wave is formed in the water but a precursor wave is induced ahead of the incident shock wave and passes the information from the water back into the air. For high incident shock Mach numbers, $M_{s}=3$ and 4, precursor waves no longer appear but instead a shock wave is formed in the water and attached to the Mach stem at every instant. The temperature field in the water is measured in the simulation. For strong incident shock waves, e.g. $M_{s}=4$, the temperature increment in the water is up to 7.3 K.

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Schiffer, Andreas, i Vito L. Tagarielli. "The response of rigid plates to blast in deep water: fluid–structure interaction experiments". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 468, nr 2145 (9.05.2012): 2807–28. http://dx.doi.org/10.1098/rspa.2012.0076.

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Laboratory-scale dynamic experiments are performed in order to explore the one-dimensional response of unsupported rigid plates to loading by exponentially decaying planar shock waves in deep water. Experiments are conducted in a transparent shock tube allowing measurements of plate motion and imparted impulse, as well as observation of cavitation in water, including motion of breaking fronts and closing fronts. Loading of both air-backed and water-backed rigid plates is examined, and the sensitivity of plate motion and imparted impulse to the structural mass and to the initial hydrostatic pressure in the water is measured. Experiments also serve to validate recently developed theoretical models, whose predictions are found to be in agreement with measurements.

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Rossano, Viola, i Giuliano De Stefano. "Computational Evaluation of Shock Wave Interaction with a Cylindrical Water Column". Applied Sciences 11, nr 11 (27.05.2021): 4934. http://dx.doi.org/10.3390/app11114934.

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Computational fluid dynamics was employed to predict the early stages of the aerodynamic breakup of a cylindrical water column, due to the impact of a traveling plane shock wave. The unsteady Reynolds-averaged Navier–Stokes approach was used to simulate the mean turbulent flow in a virtual shock tube device. The compressible flow governing equations were solved by means of a finite volume-based numerical method, where the volume of fluid technique was employed to track the air–water interface on the fixed numerical mesh. The present computational modeling approach for industrial gas dynamics applications was verified by making a comparison with reference experimental and numerical results for the same flow configuration. The engineering analysis of the shock–column interaction was performed in the shear-stripping regime, where an acceptably accurate prediction of the interface deformation was achieved. Both column flattening and sheet shearing at the column equator were correctly reproduced, along with the water body drift.

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Driels, M. R. "Estimation of the dynamic cavitation tension of water by a shock tube method". Journal of Sound and Vibration 98, nr 3 (luty 1985): 365–77. http://dx.doi.org/10.1016/0022-460x(85)90282-2.

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Hu, Hai Ying, Yu Cheng Zhang, Zhong Min Huang i Chang Xue Peng. "Experimental Study on Bubble Curtain Technology Applied in Underwater Blasting Damping". Applied Mechanics and Materials 580-583 (lipiec 2014): 73–77. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.73.

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With the further development of urban construction, engineering blasting has had a wide range of applications. However, its application environment has become more and more complex relatively. Underwater blasting, one of the applications of engineering blasting, has been increasingly used in construction of subsea tunnel and immersed tube in recent years though it has a complex influence on surroundings in operation. For the study of shock wave absorption technology of underwater blasting, this paper analyses the effectiveness of bubble curtain shielding technology used in the underwater explosion by field experiment. The test result shows that intensity of underwater shock wave approximately reduced by 80% after passing through the bubble curtain, which indicates that the bubble curtain can effectively reduce the shock wave pressure in water; vibration caused by shock wave in water approximately reduced by 20% after passing through the bubble curtain, which reflects propagation law of shock wave has changed due to the effect of the curtain.

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Dubois, François. "Simulation of strong nonlinear waves with vectorial lattice Boltzmann schemes". International Journal of Modern Physics C 25, nr 12 (grudzień 2014): 1441014. http://dx.doi.org/10.1142/s0129183114410149.

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We show that a hyperbolic system with a mathematical entropy can be discretized with vectorial lattice Boltzmann schemes using the methodology of kinetic representation of the dual entropy. We test this approach for the shallow water equations in one and two spatial dimensions. We obtain interesting results for a shock tube, reflection of a shock wave and nonstationary two-dimensional propagation. This contribution shows the ability of vectorial lattice Boltzmann schemes to simulate strong nonlinear waves in nonstationary situations.

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Melikhov, V. I., O. I. Melikhov i B. Saleh. "Model of a stationary thermal detonation wave in the “liquid lead – water” system for safety analysis of NPP with the reactor BREST-OD-300 during heat exchanger tube break accident". IOP Conference Series: Earth and Environmental Science 1154, nr 1 (1.03.2023): 012006. http://dx.doi.org/10.1088/1755-1315/1154/1/012006.

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Abstract This paper presents a mathematical model of a stationary wave of thermal detonation in the “liquid lead - water” system, which can occur after the rupture of a steam generator tube of the reactor BREST-OD-300. The model is based on the mechanics of multiphase fluid flows. The system under study includes a continuous phase of liquid lead, in which drops of water surrounded by a steam film are dispersed. Heat exchange between high-temperature molten lead and water drops is carried out in the film boiling mode. A shock wave propagating in this multiphase system causes all phases in motion. Due to the significant difference in density between liquid lead and water, a difference in velocities arises between dispersed water drops and liquid lead, which cause the fragmentation of water droplets. The shock wave velocity and amplitude are determined by constructing the shock adiabat and the Hugoniot adiabat for the parameters of the studied multiphase mixture. To describe the fragmentation of water droplets, heat transfer between phases, and interfacial friction, the empirical correlations of the thermal detonation theory are used. The obtained numerical solutions describe the distributions of parameters in the zone of melt – water interaction.

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Capanna, R., i P. M. Bardet. "High Speed PIV and Shadowgraphy Measurements in Water Hammer". Proceedings of the International Symposium on the Application of Laser and Imaging Techniques to Fluid Mechanics 20 (11.07.2022): 1–10. http://dx.doi.org/10.55037/lxlaser.20th.170.

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An experimental study addressing the challenge to measure relaxation coefficient of very fast phenomena such as water hammers is presented. A titanium projectile containing a sapphire tube containing water is accelerated and impacts a metal wall creating a water hammer. A compressed air custom built cannon is used to accelerate the projectile and create the impact leading to the water hammer. The sapphire tube, being transparent to green and UV light allows the deployment of non intrusive laser based diagnostic techniques such as Particle Image Velocimetry, Shadowgraphy, and Fiber Optic Hydrophone pressure measurements. These laser based techniques will be deployed at a very high repetition rate (>100 kHZ) to measure the relaxation coefficients between gas and water phase. First experimental results for Shadowgraphy and PIV measurements are presented. The propagation speed of shock wave in the projectile has been estimated from shadowgraphy measurements and matched the theoretical calculation. Discussion on the future development for the presented facility concludes this paper.

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Nikonov, Valeriy. "A Semi-Lagrangian Godunov-Type Method without Numerical Viscosity for Shocks". Fluids 7, nr 1 (30.12.2021): 16. http://dx.doi.org/10.3390/fluids7010016.

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One of the most important and complex effects in compressible fluid flow simulation is a shock-capturing mechanism. Numerous high-resolution Euler-type methods have been proposed to resolve smooth flow scales accurately and to capture the discontinuities simultaneously. One of the disadvantages of these methods is a numerical viscosity for shocks. In the shock, the flow parameters change abruptly at a distance equal to the mean free path of a gas molecule, which is much smaller than the cell size of the computational grid. Due to the numerical viscosity, the aforementioned Euler-type methods stretch the parameter change in the shock over few grid cells. We introduce a semi-Lagrangian Godunov-type method without numerical viscosity for shocks. Another well-known approach is a method of characteristics that has no numerical viscosity and uses the Riemann invariants or solvers for water hammer phenomenon modeling, but in its formulation the convective terms are typically neglected. We use a similar approach to solve the one-dimensional adiabatic gas dynamics equations, but we split the equations into parts describing convection and acoustic processes separately, with corresponding different time steps. When we are looking for the solution to the one-dimensional problem of the scalar hyperbolic conservation law by the proposed method, we additionally use the iterative Godunov exact solver, because the Riemann invariants are non-conserved for moderate and strong shocks in an ideal gas. The proposed method belongs to a group of particle-in-cell (PIC) methods; to the best of the author’s knowledge, there are no similar PIC numerical schemes using the Riemann invariants or the iterative Godunov exact solver. This article describes the application of the aforementioned method for the inviscid Burgers’ equation, adiabatic gas dynamics equations, and the one-dimensional scalar hyperbolic conservation law. The numerical analysis results for several test cases (e.g., the standard shock-tube problem of Sod, the Riemann problem of Lax, the double expansion wave problem, the Shu–Osher shock-tube problem) are compared with the exact solution and Harten’s data. In the shock for the proposed method, the flow properties change instantaneously (with an accuracy dependent on the grid cell size). The iterative Godunov exact solver determines the accuracy of the proposed method for flow discontinuities. In calculations, we use the iteration termination condition less than 10−5 to find the pressure difference between the current and previous iterations.

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Culbertson, Brad, i Kenneth Brezinsky. "High-Pressure Shock Tube Studies on Carbon Oxidation Reactions with Carbon Dioxide and Water". Energy & Fuels 23, nr 12 (17.12.2009): 5806–12. http://dx.doi.org/10.1021/ef900641r.

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Culbertson, Brad, i Kenneth Brezinsky. "High-pressure shock tube studies on graphite oxidation reactions with carbon dioxide and water". Proceedings of the Combustion Institute 33, nr 2 (styczeń 2011): 1837–42. http://dx.doi.org/10.1016/j.proci.2010.05.035.

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van Herwaarden, A. F., R. A. Richards, G. D. Farquhar i J. F. Angus. "'Haying-off', the negative grain yield response of dryland wheat to nitrogen fertiliser III. The influence of water deficit and heat shock". Australian Journal of Agricultural Research 49, nr 7 (1998): 1095. http://dx.doi.org/10.1071/a97041.

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Post-anthesis drought and heat shock have been implicated in previous studies as factors contributing to ‘haying-off’ in wheat, but their relative importance has not been investigated. To separate the effects, wheat plants were grown at 2 levels of nitrogen (N) and then exposed to different levels of post-anthesis water deficit in factorial combination with the presence or absence of heat shock. The growth, yield, leaf carbon exchange, water use, and the contents of protein and soluble carbohydrate were measured and compared with the field results reported in Papers I and II of this series. The experiment consisted of wheat plants (cv. Janz) grown in 1·2-m-long tubes outdoors through winter and spring in Canberra, with either nil or 240 kg N/ha applied. The tubes were supported in a refrigerated box to maintain temperatures representative of those of soil in the field, and arranged to form mini-canopies with a density of 29 plants/m2. After anthesis, half of the plants at both levels of N were watered according to their transpiration demand and the other half at 75% of demand to reduce gradually the store of soil water so that water deficit could be initiated at the same time as heat shock. Fifteen days after anthesis, different temperatures were imposed by moving half of the plants into an adjacent glasshouse where heat shock was imposed by raising the air temperature to maxima of ~35ºC for 3 days, to simulate the pattern of temperatures experienced in the field during a heat wave. During this time, the control plants experienced daily maxima of ~25ºC. Following the heat shock, all plants were placed outside and rewatered to enable the assessment of treatment effects on potential leaf function. Both water deficit and high temperature reduced assimilation. After these measurements were taken, well-watered control plants were irrigated according to transpiration demand and the plants with imposed water deficit were watered at 50% of this amount. Yields increased in response to N at both levels of water status and both levels of temperature. That is, there was no evidence of the haying-off reported in Papers I and II of this series. Two factors are proposed to account for the difference between the field crops and the plants grown in the mini-canopy here. Firstly, the pattern of soil-water use differed from the field studies reported in Paper I, with the high-N plants using more soil water than low-N plants during grain filling. Secondly, the level of water-soluble carbohydrates (WSC) in the tube-grown plants of high-N status was greater than that for plants of low-N status, which was opposite to the pattern for field-grown plants reported in Paper II. In addition, the concentrations of WSC in the tube-grown plants were higher than those in the field-grown plants, apparently because lower spike density allowed better penetration of light into the mini-canopies and led to greater assimilate storage than by the denser field crops. The results confirm the conclusion of Paper I that high temperature is not necessary for haying-off, although it is likely that it would worsen the haying-off caused by post-anthesis drought and low WSC reserves in the field. The absence of the haying-off response in this experiment was mostly because the supply of WSC from the sparse canopy was adequate to ofiset the reduction of assimilation due to water deficit and heat shock. A contributing factor to haying-off in the field may therefore be dense canopies resulting in low levels of WSC

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Cooper, Sean P., Claire M. Grégoire, Darryl J. Mohr, Olivier Mathieu, Sulaiman A. Alturaifi i Eric L. Petersen. "An Experimental Kinetics Study of Isopropanol Pyrolysis and Oxidation behind Reflected Shock Waves". Energies 14, nr 20 (18.10.2021): 6808. http://dx.doi.org/10.3390/en14206808.

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Isopropanol has potential as a future bio-derived fuel and is a promising substitute for ethanol in gasoline blends. Even so, little has been done in terms of high-temperature chemical kinetic speciation studies of this molecule. To this end, experiments were conducted in a shock tube using simultaneous CO and H2O laser absorption measurements. Water and CO formation during isopropanol pyrolysis was also examined at temperatures between 1127 and 2162 K at an average pressure of 1.42 atm. Species profiles were collected at temperatures between 1332 and 1728 K and at an average pressure of 1.26 atm for equivalence ratios of 0.5, 1.0, and 2.0 in highly diluted mixtures of 20% helium and 79.5% argon. Species profiles were also compared to four modern C3 alcohol mechanisms, including the impact of recent rate constant measurements. The Li et al. (2019) and Saggese et al. (2021) models both best predict CO and water production under pyrolysis conditions, while the AramcoMech 3.0 and Capriolo and Konnov models better predict the oxidation experimental profiles. Additionally, previous studies have collected ignition delay time (τign) data for isopropanol but are limited to low pressures in highly dilute mixtures. Therefore, real fuel–air experiments were conducted in a heated shock tube with isopropanol for stoichiometric and lean conditions at 10 and 25 atm between 942 and 1428 K. Comparisons to previous experimental results highlight the need for real fuel–air experiments and proper interpretation of shock-tube data. The AramcoMech 3.0 model over predicts τign values, while the Li et al. model severely under predicts τign. The models by Capriolo and Konnov and Saggese et al. show good agreement with experimental τign values. A sensitivity analysis using these two models highlights the underlying chemistry for isopropanol combustion at 25 atm. Additionally, modifying the Li et al. model with a recently measured reaction rate shows improvement in the model’s ability to predict CO and water profiles during dilute oxidation. Finally, a regression analysis was performed to quantify τign results from this study.

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31

Rossano, Viola, Amedeo Cittadini i Giuliano De Stefano. "Computational Evaluation of Shock Wave Interaction with a Liquid Droplet". Applied Sciences 12, nr 3 (27.01.2022): 1349. http://dx.doi.org/10.3390/app12031349.

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This article represents the natural continuation of the work by Rossano and De Stefano (2021), dealing with the computational fluid dynamics analysis of a shock wave interaction with a liquid droplet. Differently from our previous work, where a two-dimensional approach was followed, fully three-dimensional computations are performed to predict the aerodynamic breakup of a spherical water body due to the impact of a traveling shock wave. The present engineering analysis focuses on capturing the early stages of the breakup process under the shear-induced entrainment regime. The unsteady Reynolds-averaged Navier–Stokes approach is used to simulate the mean turbulent flow field in a virtual shock tube device with circular cross section. The compressible-flow-governing equations are numerically solved by means of a finite volume method, where the volume of fluid technique is employed to track the air–water interface. The proposed computational modeling approach for industrial gas dynamics applications is verified by making a comparison with reference numerical data and experimental findings, achieving acceptably accurate predictions of deformation and drift of the water body without being computationally cumbersome.

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Günther, Mattias, Ulf Arborelius, Mårten Risling, Jenny Gustavsson i Anders Sondén. "An Experimental Model for the Study of Underwater Pressure Waves on the Central Nervous System in Rodents: A Feasibility Study". Annals of Biomedical Engineering 50, nr 1 (14.12.2021): 78–85. http://dx.doi.org/10.1007/s10439-021-02898-6.

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AbstractUnderwater blast differs from blast in air. The increased density and viscosity of water relative to air cause injuries to occur almost exclusively as primary blast, and may cause disorientation in a diver, which may lead to inability to protect the airway and cause drowning. However, cognitive impairments from under water blast wave exposure have not been properly investigated, and no experimental model has been described. We established an experimental model (water shock tube) for simulating the effects of underwater blast pressure waves in rodents, and to investigate neurology in relation to organ injury. The model produced standardized pressure waves (duration of the primary peak 3.5 ms, duration of the entire complex waveform including all subsequent reflections 325 ms, mean impulse 141–281 kPa-ms, mean peak pressure 91–194 kPa). 31 rats were randomized to control (n = 6), exposure 90 kPa (n = 8), 152 kPa (n = 8), and 194 kPa (n = 9). There was a linear trend between the drop height of the water shock tube and electroencephalography (EEG) changes (p = 0.014), while no differences in oxygen saturation, heart rate, S100b or macroscopic bleedings were detected. Microscopic bleedings were detected in lung, intestines, and meninges. Underwater pressure waves caused changes in EEG, at pressures when mild hemorrhage occurred in organs, suggesting an impact on brain functions. The consistent injury profile enabled for the addition of future experimental interventions.

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Govindaraj, Santhiya, i Stalin Viswanathan. "Pneumomediastinum and bilateral pneumothorax following near drowning in shallow water". Clinics and Practice 1, nr 3 (3.10.2011): 70. http://dx.doi.org/10.4081/cp.2011.e70.

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We report pneumomediastinum, bilateral pneumothorax and acute respiratory distress syndrome in a victim of near drowning who was intoxicated and did not have thoracic or neck trauma. Chest radiograph revealed the above findings, later confirmed by computed tomography. He was in shock and also had gastrointestinal (GI) bleeding and renal dysfunction. With adequate resuscitative measures including fluids, blood transfusions, intercostal tube drainage and mechanical ventilation he made a complete recovery. Good prognostic indicators in near drowning patients include higher Glasgow Coma Scale, short submersion time and quick resuscitative measures even in the presence of serious cardiorespiratory or hemodynamic compromise.

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MAHMOUD, N. H. "THEORETICAL AND EXPERIMENTAL STUDY OF A SHOCK TUBE PERFORMANCE WITH HOMOGENEOUS NUCLEATION OF WATER VAPOUR". ERJ. Engineering Research Journal 24, nr 3 (1.07.2001): 127–45. http://dx.doi.org/10.21608/erjm.2001.71055.

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Mathieu, Olivier, Clayton Mulvihill i Eric L. Petersen. "Shock-tube water time-histories and ignition delay time measurements for H2S near atmospheric pressure". Proceedings of the Combustion Institute 36, nr 3 (2017): 4019–27. http://dx.doi.org/10.1016/j.proci.2016.06.027.

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Peters, F., i B. Paikert. "Nucleation and growth rates of homogeneously condensing water vapor in argon from shock tube experiments". Experiments in Fluids 7, nr 8 (wrzesień 1989): 521–30. http://dx.doi.org/10.1007/bf00187403.

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Wei, Ya Nan, Fei Fei Zhang, Bo Wei, Hui Xu i Kai He. "Experimental and Numerical Analyses of Tubular Electrohydraulic Forming Process". Key Engineering Materials 871 (styczeń 2021): 80–86. http://dx.doi.org/10.4028/www.scientific.net/kem.871.80.

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Electrohydraulic forming (EHF) is a kind of high speed forming process, which deforms the metal by shock wave through instantaneous discharge of high voltage in water. Compared with the traditional forming methods, this high speed forming process can greatly improve the formability of the materials. There are many processing factors that affect the forming efficiency and performance of the electrohydraulic forming process, one of which is the discharge voltage between the electrodes. In this paper, three electrohydraulic forming experiments with various die shapes were carried out under various discharge voltage conditions. And the bulge height and axial length of the aluminum alloy A6061 tubes under different conditions were compared. Besides, finite element numerical simulation was also performed to quantitatively investigate the deformation history of the tube.

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38

Young, Laurence R. "Making Army Helmets Tougher and Safer with Realistic Simulation". AM&P Technical Articles 170, nr 8 (1.08.2012): 31–33. http://dx.doi.org/10.31399/asm.amp.2012-08.p031.

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Abstract Researchers at MIT have evaluated a wide range of helmet liner designs and materials for potential use in the U.S. Army's advanced combat helmet (ACH). To measure the effectiveness of candidate materials, the investigators rely on finite-element simulations that are validated by shock tube testing at Purdue University. Of the various filler materials examined, glass beads, glycerin, and water show the most promise for blast attenuation.

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39

Yang, Xingtuan, Yanfei Sun, Huaiming Ju i Shengyao Jiang. "Procedure of Active Residual Heat Removal after Emergency Shutdown of High-Temperature-Gas-Cooled Reactor". Science and Technology of Nuclear Installations 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/583597.

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After emergency shutdown of high-temperature-gas-cooled reactor, the residual heat of the reactor core should be removed. As the natural circulation process spends too long period of time to be utilized, an active residual heat removal procedure is needed, which makes use of steam generator and start-up loop. During this procedure, the structure of steam generator may suffer cold/heat shock because of the sudden load of coolant or hot helium at the first few minutes. Transient analysis was carried out based on a one-dimensional mathematical model for steam generator and steam pipe of start-up loop to achieve safety and reliability. The results show that steam generator should be discharged and precooled; otherwise, boiling will arise and introduce a cold shock to the boiling tubes and tube sheet when coolant began to circulate prior to the helium. Additionally, in avoiding heat shock caused by the sudden load of helium, the helium circulation should be restricted to start with an extreme low flow rate; meanwhile, the coolant of steam generator (water) should have flow rate as large as possible. Finally, a four-step procedure with precooling process of steam generator was recommended; sensitive study for the main parameters was conducted.

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40

Yoshida, T., i K. Takayama. "Interaction of Liquid Droplets With Planar Shock Waves". Journal of Fluids Engineering 112, nr 4 (1.12.1990): 481–86. http://dx.doi.org/10.1115/1.2909431.

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Interactions and breakup processes of 1.50-mm-diameter ethyl alcohol droplets and 5.14-mm-diameter water bubbles with planar shock waves were observed using double-exposure holographic interferometry. Experiments were conducted in a 60 mm × 150 mm cross-sectional shock tube for shock Mach number 1.56 in air. The Weber numbers of droplets and liquid bubbles were 5.6 × 103 and 2.9 × 103, respectively, while the corresonding Reynolds numbers were 4.2 × 10 and 1.5 × 105. It is shown that the resulting holographic interferogram can eliminate the effect of the mists produced by the breakup of the droplets and clearly show the structure of a disintegrating droplet and its wake. This observation was impossible by conventional optical flow visualization. It is demonstrated that the time variation of the diameter of a breaking droplet measured by conventional optical techniques has been overestimated by up to 35 percent.

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41

Chudanov, Vladimir V., Anna E. Aksenova, Alexey A. Leonov i Artem A. Makarevich. "GPU and CPU Numerical Simulation of tTwo-Phase Mixtures with Phase Transition". WSEAS TRANSACTIONS ON HEAT AND MASS TRANSFER 16 (7.05.2021): 43–48. http://dx.doi.org/10.37394/232012.2021.16.7.

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The article presents the direct simulation results of two-phase mixtures with phase transition shock tube in dodecane, two-phase expansion tube in water and 2D heat and mass transfer in a vertical channel with sodium. For two versions of the code for CPU and GPU calculations possess efficient scaling in the wide range of grid sizes. Scaling for CPU version of the code is close to ideal and does not depend from the grid size and the number of nodes. Efficiency of scaling for GPU version of the code is limited by the size of calculation region per 1 node and could be varied for different models of processor. The value of scaling factor was demonstrated.

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42

Bruce Ralphin Rose, J., S. Dhanalakshmi i G. R. Jinu. "Experimental and numerical analysis of compressible two-phase flows in a shock tube". International Journal of Modeling, Simulation, and Scientific Computing 06, nr 03 (wrzesień 2015): 1550025. http://dx.doi.org/10.1142/s1793962315500257.

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The comparative study on seven equation models with two different six equations model for compressible two-phase flow analysis is proposed. The seven equations model is derived for compressible two-phase flow that is in the nonconservation form. In the present work, two different six equations model are derived for two pressures, two velocities and single temperature with the derivation of the equation of state. The closing equation for one of the six equations model is energy conservation equation while another one is closed by entropy balance equation. The partial differential form of governing equations is hyperbolic and written in the conservative form. At this point, the set of governing equations are derived based on the principle of extended thermodynamics. The method of solving single temperature from both six equation models are simple and direct solution can be obtained. Numerical simulation has been tried using one of the six equation models for air–water shock tube problems. Explicit fourth order Runge–Kutta scheme is used with Finite Volume Shock Capturing method for solving the governing equations numerically. The pressure, velocity and volume fraction variations are captured along the shock tube length through flow solver. Experimental work is carried out to magnify the initial stage of liquid injection into a gas. The outcome of six equations model for compressible two-phase flow has revealed the multi-phase flow characteristics that are similar to the actual conditions.

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43

Chandran R, Jishnu, i A. Salih. "A modified equation of state for water for a wide range of pressure and the concept of water shock tube". Fluid Phase Equilibria 483 (marzec 2019): 182–88. http://dx.doi.org/10.1016/j.fluid.2018.11.032.

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44

Bolotnova, R. Kh, i E. F. Gainullina. "Modeling of weak shock waves propagation in aqueous foam layer". Journal of Physics: Conference Series 2103, nr 1 (1.11.2021): 012217. http://dx.doi.org/10.1088/1742-6596/2103/1/012217.

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Abstract Dynamics of low-intensity air shock waves in the shock tube containing an aqueous foam layer is theoretically investigated. Modeling of studied process is carried out using two-phase model of aqueous foam developed by the authors in single-pressure, single-speed and two-temperature approximations. The model takes into account the Ranz-Marshall interphase contact heat transfer, effective Herschel-Bulkley viscosity, which describes foam behavior as a non-Newtonian fluid, and elastic properties of aqueous foam under a weak shock impaction without destruction of foam structure. Properties of air and water as the foam components are described by realistic equations of state. Computer implementation of the aqueous foam model is carried out in the solver, developed by the authors in OpenFOAM software. The influence of aqueous foam viscoelastic properties on the intensity and structure of a shock wave has been investigated. When analyzing the obtained solutions, reliability of the proposed model and method of numerical modeling is estimated by comparative analysis of the found solutions and literature experimental data.

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45

van der Grinten, Jos G. M., Marinus E. H. van Dongen i Hans van der Kogel. "A shock‐tube technique for studying pore‐pressure propagation in a dry and water‐saturated porous medium". Journal of Applied Physics 58, nr 8 (15.10.1985): 2937–42. http://dx.doi.org/10.1063/1.335841.

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46

Mataradze, Edgar, Nikoloz Chikhradze, Nika Bochorishvili, Irakli Akhvlediani i Dimitri Tatishvili. "Experimental Study of the Effect of Water Mist Location On Blast Overpressure Attenuation in A Shock Tube". IOP Conference Series: Earth and Environmental Science 95 (grudzień 2017): 042031. http://dx.doi.org/10.1088/1755-1315/95/4/042031.

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Grégoire, Claire M., Charles K. Westbrook, Sulaiman A. Alturaifi, Olivier Mathieu i Eric L. Petersen. "Shock‐tube spectroscopic water measurements and detailed kinetics modeling of 1‐pentene and 3‐methyl‐1‐butene". International Journal of Chemical Kinetics 53, nr 1 (12.09.2020): 67–83. http://dx.doi.org/10.1002/kin.21426.

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48

Zink, Brian J., Susan A. Stern, Brian D. McBeth, Xu Wang i Michelle Mertz. "Effects of ethanol on limited resuscitation in a model of traumatic brain injury and hemorrhagic shock". Journal of Neurosurgery 105, nr 6 (grudzień 2006): 884–93. http://dx.doi.org/10.3171/jns.2006.105.6.884.

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Object Limited resuscitation following uncontrolled hemorrhagic shock (HS) has been associated with improved outcomes in various animal models, although it has not been previously studied in the setting of traumatic brain injury (TBI) and ethanol intoxication. The aim of the present study was to determine the effects of ethanol intoxication in a model of experimental TBI and HS treated with limited resuscitation. Methods After induction of anesthesia and the placement of instruments, swine were subjected to a fluid-percussion injury of 3 atm. Simultaneously, hemorrhage was induced from an arterial catheter via a computerized roller pump to a mean arterial blood pressure (MABP) of 50 mm Hg, at which time uncontrolled hemorrhage was induced by the creation of an aortic tear. When the MABP decreased to 30 mm Hg, limited resuscitation to a MABP of 60 mm Hg was begun. After 60 minutes, animals were aggressively resuscitated to baseline MABP levels. Two groups of animals were studied: those receiving tap water by gastrostomy tube and those receiving ethanol (4 g/kg) by gastrostomy tube. Animals were monitored for 180 minutes after TBI. Hemorrhage volumes were significantly greater in ethanol-infused animals (mean ± standard deviation, 41 ± 34 mm Hg) compared with tap water–infused animals (17 ± 18 mm Hg; p = 0.048). Resuscitation requirements were significantly higher and metabolic parameters significantly worse in the ethanol group. Survival time was also significantly decreased in the animals infused with ethanol (81 ± 60 minutes) compared with those infused with tap water (130 ± 51 minutes; p = 0.035). Conclusions Ethanol intoxication led to increased hemorrhage volume and worsened hemodynamic and metabolic profiles in this model of limited resuscitation after TBI and HS. Ethanol-exposed animals had increased resuscitation requirements and decreased survival times.

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Ivashnyov, Oleg E., i Marina N. Ivashneva. "Vapour explosion under hot water depressurization". Journal of Fluid Mechanics 812 (22.12.2016): 65–128. http://dx.doi.org/10.1017/jfm.2016.783.

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This paper continues a series of works developing a model for a high-speed boiling flow capable of describing different fluxes with no change in the model coefficients. Refining the interfacial area transport equation in partial derivatives, we test the ability of the model to describe phenomena that cannot be simulated by models that average the interfacial interaction. In the previous version, the possibility for bubble fragmentation was considered, which permitted us to reproduce an explosive boiling in rarefaction shocks moving at a speed of ${\sim}10~\text{m}~\text{s}^{-1}$ fixed in experiments on hot water decompression. The shocks were shown to be caused by a chain bubble fragmentation leading to a sharp increase in the interphase area (Ivashnyov et al., J. Fluid Mech., vol. 413, 2000, pp. 149–180). With no change in the free parameters (the initial number of boiling centres in the flow bulk and the critical Weber number) chosen for a tube decompression, the model gave close predictions for critical flows in long nozzles, $L/D\sim 100$. The formation of a boiling shock in the nozzle was shown to be the reason for the onset of autovibrated regimes (Ivashnyov & Ivashneva, J. Fluid Mech., vol. 710, 2012, pp. 72–101). However, the previous model does not simulate the phenomenon of a vapour explosion at a primary stage of a hot water decompression, when the first rarefaction wave is followed by an extended, 1 m width, several MPa amplitude compression wave in which the pressure reaches a plateau below a saturation value. The model proposed assumes initial boiling centre origination at the channel walls. Due to overflowing, the wall bubbles break up, with their fragments passing into the flow. On growing up, the flow bubbles can break up in their turn. It is shown that an extended compression wave is caused by the fragmentation of wall bubbles, which leads to the increase in the interphase area, boiling intensification and the pressure rise. The pressure reaches a plateau before a saturation state is reached due to flow momentum loss accelerating the fragments of wall bubbles. The phenomenon of pressure ‘oscillation’ fixed in some experimental oscillograms when the pressure in the compression wave increases up to a saturation pressure and then drops to the plateau value has been explained as well. The ‘illposedness’ defect of the generally accepted model for two-phase two-velocity flow with a compressible carrying phase, which lies in its complex characteristics, has been rectified. The calculations of a stationary countercurrent liquid-particle flow in a diffuser with the improved hyperbolic model predicts a critical regime with a maximal liquid mass flux, while the old non-hyperbolic model simulates the supercritical regimes with ‘numerical instabilities’. Calculations of a transient upward flow of particles have shown the formation of a superslow ‘creeping’ shock wave of particles compacting.

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50

Tan, M. J., i J. M. Delhaye. "An Experimental Study of Liquid Entrainment by Expanding Gas". Journal of Fluids Engineering 109, nr 4 (1.12.1987): 436–41. http://dx.doi.org/10.1115/1.3242685.

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An experimental study of the hydrodynamic aspect of the expansion process in a hypothetical core disruptive accident (HCDA) by means of a shock-tube technique is described. The working fluid pair was water-air. Interface displacement data for shock strengths in the range 0.5–3.0 were obtained by means of high-speed photography. The displacement data are fitted into least-square polynomials in time, which are used to compute accelerations and entrainment velocities. The accelerations thus obtained, which are in the range 950 m/s2−15,000 m/s2, are uniform in time. The entrainment velocities for experiments performed with the circular driven section are consistently higher than those for the experiments performed with the square driven section at the same accelerations. The difference is attributed to the entrainment velocity for the latter case being time-dependent. Furthermore, an upper bound on the rate of entrainment in an HCDA is proposed.

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