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Mass flow rate effect on a rotating detonation combustor with an axial air injection Shock Waves (IF 1.248) Pub Date : 2021-02-17 T. Sato, F. Chacon, M. Gamba, V. Raman
Changing the flow rate of reactants being injected into a rotating detonation combustor (RDC) results in interesting behavior of the system. Prior studies have found that an increase in mass flow rate gradually increases the detonation wave speed before splitting the wave into multiple fronts. The focus of this study is in understanding the physics of such behavior through a combination of experiments
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An experimental study on the control of plug nozzle jets Shock Waves (IF 1.248) Pub Date : 2021-02-12 A. Khan, A. S. Bhesania, R. Kumar
Experimental studies are performed for the near- and far-field characteristics of a plug nozzle jet with the objective to see the effect of truncation of the plug on mean flow characteristics of the jet and its control using vortex generators (VGs). To this end, the plug is truncated at 50%, 40%, and 30% of the axial length from the throat, and mean flow characteristics are studied by the schlieren
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The TNT and ANFO equivalences of the Beirut explosion Shock Waves (IF 1.248) Pub Date : 2021-02-09 J. M. Dewey
On 4 August 2020, an estimated 2.75 kt of ammonium nitrate exploded in the Port of Beirut, Lebanon. Rigby et al. (Shock Waves 30:671–675, 2020) used observations from numerous video recordings of the explosion to estimate the time-of-arrival of the primary shock at 38 positions, the distances of which from the centre of the explosion were determined from Google maps. These data were analysed to make
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Role of O 3 addition in the deflagration-to-detonation transition of an ethylene–oxygen mixture in a macroscale tube Shock Waves (IF 1.248) Pub Date : 2021-01-13 C. Wang, G. T. Gu, W. H. Han, Y. Cai
Deflagration-to-detonation transition (DDT) in a macroscale tube is investigated experimentally for stoichiometric ethylene–oxygen with O3 (ozone) addition. The effect of O3 addition on the DDT process is studied, including its dependence on initial pressure. This kinetic effect of ozone addition was investigated by examining the influence of ozone self-decomposition and ethylene ozonolysis on ignition
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In situ nozzle reservoir thermometry by laser-induced grating spectroscopy in the HELM free-piston reflected shock tunnel Shock Waves (IF 1.248) Pub Date : 2021-01-09 C. Selcan, T. Sander, Ch. Mundt
Experimental determination of test gas caloric quantities in high-enthalpy ground testing is impeded by excessive pressure and temperature levels as well as minimum test timescales of short-duration facilities. Yet, accurate knowledge of test gas conditions and stagnation enthalpy prior to nozzle expansion is crucial for a valid comparison of experimental data with numerical results. To contribute
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Rotating detonation waves in annular gap with variable stagnation pressure Shock Waves (IF 1.248) Pub Date : 2021-01-07 V. A. Levin, I. S. Manuylovich, V. V. Markov
We consider a three-dimensional unsteady flow with one, two, or four rotating detonation waves arising in an annular gap of an axially symmetric device between two parallel planes perpendicular to its symmetry axis. The corresponding problem is formulated and studied. It is assumed that there is a reservoir with quiescent homogeneous propane–air combustible mixture with given stagnation parameters;
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Specific heat effects in two-dimensional shock refractions Shock Waves (IF 1.248) Pub Date : 2021-01-04 D. Martínez-Ruiz, C. Huete, P. J. Martínez-Ferrer, D. Mira
Compressible mixtures in supersonic flows are subject to significant temperature changes via shock waves and expansions, which affect several properties of the flow. Besides the widely studied variable transport effects such as temperature-dependent viscosity and conductivity, vibrational and rotational molecular energy storage is also modified through the variation of the heat capacity \(c_p\) and
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Proton radiography of explosively dispersed metal particles with varying volume fraction and varying carrier phase Shock Waves (IF 1.248) Pub Date : 2021-01-04 K. T. Hughes, J. J. Charonko, K. P. Prestridge, N. H. Kim, R. T. Haftka, S. Balachandar
A series of experiments were performed to provide validation data for explosively driven multiphase flows at moderate-to-high volume fractions. A \(13 \times 6\) mm cylindrical packet of 115-\(\upmu \)m steel particles was dispersed explosively. In contrast to shock tube studies, the particles were subjected to a high-Mach-number shock, in the presence of an ambient fluid, and a contact interface between
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Numerical simulations on propane/oxygen detonation in a narrow channel using a detailed chemical mechanism: formation and detailed structure of irregular cells Shock Waves (IF 1.248) Pub Date : 2020-12-19 N. Takeshima, K. Ozawa, N. Tsuboi, A. K. Hayashi, Y. Morii
Numerical simulations of two-dimensional inviscid detonations for a stoichiometric propane/oxygen gas mixture are performed using a detailed chemical reaction model. The UC San Diego model which includes 57 chemical species and 268 elementary reactions is mainly used in the present study. It is shown that a grid size of 3 µm can capture important features such as the unburned gas pocket behind the
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Effect of hydroxyl radical precursor addition on LTC-affected detonation in DME– $$\hbox {O}_{{2}}$$ O 2 – $$\hbox {CO}_{{2}}$$ CO 2 mixtures Shock Waves (IF 1.248) Pub Date : 2020-11-25 Y. Z. He, R. Mével
The effects of hydrogen peroxide (\(\hbox {H}_{2}\hbox {O}_{2}\)) and tert-butyl hydroperoxide (TBHP), both hydroxyl radical precursors, on the characteristic length-scales of low-temperature-chemistry-affected (LTC-affected) detonation propagating in dimethyl-ether–oxygen–carbon-dioxide (DME–\(\hbox {O} _{2}\)–\(\hbox {CO}_{2}\)) mixtures were investigated using the Zeldovich–von Neumann–Döring model
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Effect of concentration inhomogeneity on the pulsating instability of hydrogen–oxygen detonations Shock Waves (IF 1.248) Pub Date : 2020-11-19 W. J. Ma, C. Wang, W. H. Han
One-dimensional, unsteady gaseous detonation propagation in a non-homogeneous medium is investigated numerically using the reactive, compressible Navier–Stokes equations with detailed chemistry. The effect of concentration inhomogeneity on the pulsating mode is modeled by a sinusoidal distribution of H2 mole fraction in a H2–O2 mixture. The mixture inhomogeneity, varied by changing the disturbance
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Shock wave structure in non-ideal dilute gases under variable Prandtl number Shock Waves (IF 1.248) Pub Date : 2020-11-04 D. Khapra, A. Patel
This paper investigates the structure of normal shock waves for a planar steady flow of non-ideal dilute gases under variable viscosity and thermal conductivity using the Navier–Stokes–Fourier approach to the continuum model. The gas is assumed to follow the simplified van der Waals equation of state along with the power-law temperature-dependent coefficients of shear viscosity, bulk viscosity, and
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Dynamic mode decomposition analysis of rotating detonation waves Shock Waves (IF 1.248) Pub Date : 2020-11-03 M. D. Bohon, A. Orchini, R. Bluemner, C. O. Paschereit, E. J. Gutmark
A rotating detonation combustor (RDC) is a novel approach to achieving pressure gain combustion. Due to the steady propagation of the detonation wave around the perimeter of the annular combustion chamber, the RDC dynamic behavior is well suited to analysis with reduced-order techniques. For flow fields with such coherent aspects, the dynamic mode decomposition (DMD) has been shown to capture well
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Impulse force-measurement system Shock Waves (IF 1.248) Pub Date : 2020-10-14 Y. Wang, Z. Jiang
Shock tunnels are important ground test facilities that can generate high-enthalpy flow. Flight velocity at a high Mach number can be simulated for aerodynamic testing of chemically reacting flows. However, the application of these tunnels is limited due to the only milliseconds-long test duration, especially for aerodynamic force measurement using traditional strain gauge balances. This study presents
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A 3-D pseudo-arc-length moving-mesh method for numerical simulation of detonation wave propagation Shock Waves (IF 1.248) Pub Date : 2020-10-13 T. Ma, J. Zhao, J. Ning
In this paper, we propose a robust pseudo-arc-length moving-mesh method (PALM) which adopts the strategy of overall movement and block calculation for numerical simulation of detonation wave propagation in three dimensions. The pseudo-arc-length moving-mesh method involves governing equations’ evolution, mesh redistribution, and positivity-preserving analysis. Second-order finite-volume schemes and
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Numerical investigation of detonation initiation by a focusing shock wave Shock Waves (IF 1.248) Pub Date : 2020-10-06 S. Bengoechea, J. Reiss, M. Lemke, J. Sesterhenn
This work presents a numerical study of detonation initiation by means of a focusing shock wave. The investigated geometry is a part of a pulsed detonation combustion chamber, consisting of a circular pipe in which the flow is obstructed by a single convergent–divergent axisymmetric nozzle. This obstacle acts as a focusing device for an incoming shock wave, serving as a low-energy detonation initiator
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Blast wave modification by detonator placement Shock Waves (IF 1.248) Pub Date : 2020-09-29 C. Needham, J. Brisby, D. Ortley
The blast wave generated by a high explosive detonation is dependent not only on the shape of the charge but on the location of the detonator or detonators. Even for a spherical charge, the blast wave can be very asymmetric if the initiation is not at the center of the charge. The asymmetry is even greater for cylindrical charges. High-resolution, high-fidelity calculations of the blast wave generated
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Computation of the mean hydrodynamic structure of gaseous detonations with losses Shock Waves (IF 1.248) Pub Date : 2020-09-27 M. Reynaud, S. Taileb, A. Chinnayya
In this paper, computations of gaseous detonations in several configurations are performed and discussed. The objective is to investigate the detonation characteristics, specially the influence of losses, through a quantitative analysis of the mean hydrodynamic structure. The results are divided into two parts: The first one relates to the propagation of ideal detonations without losses and to their
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Detonability of fuel–air mixtures Shock Waves (IF 1.248) Pub Date : 2020-09-23 S. M. Frolov, V. I. Zvegintsev, V. S. Aksenov, I. V. Bilera, M. V. Kazachenko, I. O. Shamshin, P. A. Gusev, M. S. Belotserkovskaya
A new experimental method for evaluating the detonability of fuel–air mixtures (FAMs) based on measuring the deflagration-to-detonation (DDT) run-up distance and/or time in a standard pulse detonation tube (SDT) is used to rank gaseous premixed and non-premixed FAMs by their detonability under substantially identical thermodynamic and gasdynamic conditions. In the experiments, FAMs based on hydrogen
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Development of a new empirical formula for prediction of triple point path Shock Waves (IF 1.248) Pub Date : 2020-09-22 W. Xiao, M. Andrae, N. Gebbeken
This paper develops a new empirical formula for the prediction of the triple point path in irregular shock reflection cases. Numerical simulations using a two-dimensional axisymmetric multi-material arbitrary Lagrangian–Eulerian formulation are employed to obtain the data of fluid density. Using the data of fluid density and nodal coordinates, the gradients of fluid density are determined and then
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Preliminary yield estimation of the 2020 Beirut explosion using video footage from social media Shock Waves (IF 1.248) Pub Date : 2020-09-22 S. E. Rigby, T. J. Lodge, S. Alotaibi, A. D. Barr, S. D. Clarke, G. S. Langdon, A. Tyas
Rapid, accurate assessment of the yield of a large-scale urban explosion will assist in implementing emergency response plans, will facilitate better estimates of areas at risk of high damage and casualties, and will provide policy makers and the public with more accurate information about the event. On 4 August 2020, an explosion occurred in the Port of Beirut, Lebanon. Shortly afterwards, a number
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The structure of shock waves propagating through heavy noble gases: temperature dependence Shock Waves (IF 1.248) Pub Date : 2020-09-12 F. C. Dias, F. Sharipov
The structure of planar shock waves propagating through argon, xenon, and krypton is calculated using the direct simulation Monte Carlo method for Mach numbers 2, 5, and 10. The upstream temperature considered in the present paper varies from 30 to 8000 K, depending on the gas species and Mach number. Both quantum and classical approaches to the intermolecular collisions based on ab initio potential
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Mechanisms of detonation initiation in multi-focusing systems Shock Waves (IF 1.248) Pub Date : 2020-09-08 P. S. Utkin, A. I. Lopato, A. A. Vasil’ev
The work is dedicated to the experimental and numerical study of the mechanisms of gaseous detonation initiation in a stoichiometric hydrogen–oxygen mixture due to the reflection of a shock wave from a complex-shaped end wall. Several elliptic surfaces of different geometries, including distributed ones, were considered. We refer to such reflectors with multiple elliptical surfaces as multi-focusing
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Blast mitigation by water mist: the effect of the detonation configuration Shock Waves (IF 1.248) Pub Date : 2020-09-07 T. Schunck, M. Bastide, D. Eckenfels, J.-F. Legendre
In this paper, blast mitigation using water mist was evaluated to assess the operational capability of the use of firefighting systems implemented in ships or infrastructures to reduce blast effects. In particular, we tried to determine the mitigation that could be obtained in specific situations. A tunnel equipped with a water mist system enabled us to assess the mitigation impact of water mist on
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Extension of geometrical shock dynamics for blast wave propagation Shock Waves (IF 1.248) Pub Date : 2020-09-01 J. Ridoux, N. Lardjane, L. Monasse, F. Coulouvrat
The direct numerical simulation of blast waves is a challenging task due to the wide range of spatial and temporal scales involved. Moreover, in a real environment (topography, urban area), the blast wave interacts with geometrical obstacles, resulting in reflection, diffraction, and wave recombination phenomena. The shape of the front becomes complex, which limits the efficiency of simple empirical
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Effect of incident laser sheet orientation on the OH-PLIF imaging of detonations Shock Waves (IF 1.248) Pub Date : 2020-08-31 K. P. Chatelain, R. Mével, J. Melguizo-Gavilanes, A. Chinnayya, S. Xu, D. A. Lacoste
This study aims to investigate the effect of laser sheet orientation on the OH-planar laser-induced fluorescence (OH-PLIF) imaging of a detonation wave and to identify the potential benefit of using a transverse laser orientation, compared to the conventional frontal orientation. In this study, we developed a new laser-induced fluorescence (LIF) model, based on a preexisting one, to include a more
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Effects of unequal blockage ratio and obstacle spacing on wave speed and overpressure during flame propagation in stoichiometric H 2 /O 2 Shock Waves (IF 1.248) Pub Date : 2020-08-03 C. Brunoro Ahumada, Q. Wang, E. L. Petersen
Experiments on flame propagation and detonation onset behind two solid obstructions were carried out in premixed stoichiometric hydrogen–oxygen mixtures at 20 kPa in a closed-ended tube. Obstacles with three different blockage ratios (25%, 40%, and 80%) were used, and the arrangement between the obstacles was changed in terms of blockage distribution (increasing, decreasing, and equivalent); obstacle
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Modelling of vibrational nonequilibrium effects on the H 2 –air mixture ignition under shock wave conditions in the state-to-state and mode approximations Shock Waves (IF 1.248) Pub Date : 2020-07-28 I. N. Kadochnikov; I. V. Arsentiev
Kinetics of physicochemical processes occurring during combustion of a hydrogen–air mixture initiated by a shock wave was studied using state-to-state and mode models that take into account nonequilibrium vibrational excitation of N2, O2, H2, and OH molecules. The effect of vibrational–translational relaxation on the induction time was considered: it was shown that the delay in establishing thermodynamic
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Understanding the effects of blast loads on open spaces and enclosed structures in simulations and experiments Shock Waves (IF 1.248) Pub Date : 2020-07-20 T. Roh, Y. Lee, W. Lee, J. J. Yoh
When a high explosive detonates, a large amount of energy is released within a short time, creating a high-temperature and high-pressure environment accompanied by a blast wave. When the blast wave interacts with field obstacles such as building structures and ground soil, it produces a reflected wave. The complexity of the pressure field created by blast waves depends on the spatial characteristics
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Propagation of near-limit gaseous detonations in rough-walled tubes Shock Waves (IF 1.248) Pub Date : 2020-07-20 T. Ren, Y. Yan, H. Zhao, J. H. S. Lee, H. D. Ng
In this study, experiments were carried out to investigate the detonation velocity behavior near limits in rough-walled tubes. The wall roughness was introduced by using different spiral inserts in 76.2-mm-diameter, 50.8-mm-diameter, 38.1-mm-diameter, and 25.4-mm-diameter tubes. Different pre-mixed mixtures, CH4 + 2O2, C2H2 + 2.5O2, C2H2 + 2.5O2 + 70%Ar, and 2H2 + O2 were tested in the experiments
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Effect of oxygen atom precursors addition on LTC-affected detonation in $${\hbox {DME}}{-}{\hbox {O}}_{2}{-}{\hbox {CO}}_{2}$$ DME - O 2 - CO 2 mixtures Shock Waves (IF 1.248) Pub Date : 2020-07-06 R. Mével, Y. Z. He
The effects of ozone \(({\hbox {O}}_{3})\) or nitrogen dioxide \(({\hbox {NO}}_{2})\) as oxygen atom precursors on the characteristic length-scales of low-temperature chemistry (LTC)-affected detonation propagating in dimethyl \({\hbox {ether}}{-}{\hbox {O}}_{2}{-}{\hbox {CO}}_{2}\) mixtures were investigated using the Zeldovich–von Neumann–Döring model. The effect of these two additives on the energy
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Influence of cellophane diaphragm rupture processes on the shock wave formation in a shock tube Shock Waves (IF 1.248) Pub Date : 2020-06-26 G. Fukushima; T. Tamba; A. Iwakawa; A. Sasoh
Diaphragm opening processes with a finite time affect the generated shock waves and shock tube flows. This effect is dominant in short and low-pressure shock tubes. In this research, a high-speed visualization of the opening process of a cellophane diaphragm, which is a suitable material for operation in a low-pressure shock tube, is conducted. The self-shaping opening morphology of cellophane diaphragms
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Reinterpreting shock wave structure predictions using the Navier–Stokes equations Shock Waves (IF 1.248) Pub Date : 2020-06-24 M. H. L. Reddy; S. K. Dadzie
Classical Navier–Stokes equations fail to predict shock wave profiles accurately. In this paper, the Navier–Stokes system is fully transformed using a velocity variable transformation. The transformed equations termed the recast Navier–Stokes equations display physics not initially included in the classical form of the equations. We then analyze the stationary shock structure problem in a monatomic
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Studies of the TNT equivalence of propane, propane/oxygen, and ANFO Shock Waves (IF 1.248) Pub Date : 2020-06-18 J. M. Dewey
The TNT equivalences of equal masses of propane, a stoichiometric mixture of propane and oxygen, and ammonium-nitrate–fuel-oil (ANFO) were calculated based on the peak hydrostatic and dynamic pressures, the hydrostatic and dynamic pressure positive-phase impulses, and the positive-phase integrated work flux. It was assumed that the propane had been dispersed as a vapour/droplet cloud to form a stoichiometric
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Brightness temperature of water compressed by a double shock to pressures of 60–79 GPa Shock Waves (IF 1.248) Pub Date : 2020-06-16 S. A. Bordzilovskii; S. M. Karakhanov; K. V. Khishchenko
New data on the temperature of water shock-compressed to 79 GPa are presented. Thermal radiation from a water layer compressed by incident shock waves and shock waves reflected from a lithium fluoride or sapphire window was recorded in the range of incident-wave intensity of 28–36 GPa. The reflected-wave pressures were in the range of 49–79 GPa. The temperature measured at the pressure of 79 GPa was
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Structure–property linkage in shocked multi-material flows using a level-set-based Eulerian image-to-computation framework Shock Waves (IF 1.248) Pub Date : 2020-06-12 S. Roy; N. K. Rai; O. Sen; H. S. Udaykumar
Morphology and dynamics at the mesoscale play crucial roles in the overall macro- or system-scale flow of heterogeneous materials. In a multi-scale framework, closure models upscale unresolved sub-grid (mesoscale) physics and therefore encapsulate structure–property (S–P) linkages to predict performance at the macroscale. This work establishes a route to S–P linkage, proceeding all the way from imaged
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Using optically filtered high-speed imaging to characterise expansion tube operating conditions Shock Waves (IF 1.248) Pub Date : 2020-06-09 C. M. James; D. R. Smith; C. McLean; R. G. Morgan; S. W. Lewis; P. Toniato; H. Wei; T. J. McIntyre
Traditionally, Pitot rake test models have been used to take time- and spatially resolved impact pressure measurements in impulse facilities for flow characterisation. When expansion tubes are used for the study of hypervelocity planetary entry phenomena, generally the post-shock flow in the test section strongly radiates. This paper outlines a simple method which uses a high-speed camera in addition
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Influence of the explosion center on shock wave propagation in a confined room Shock Waves (IF 1.248) Pub Date : 2020-05-29 K. Gault; I. Sochet; L. Hakenholz; A. Collignon
It is well established that the knowledge about shock wave propagation in the free field cannot be applied to confined environments, especially when it comes to predicting the reflected shock wave. With the increase in accidental or intentional detonations of explosives in confined or urban environments, it is important to study and thoroughly understand the propagation of shock waves to provide behavior
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Near-limit detonations of methane–oxygen mixtures in long narrow tubes Shock Waves (IF 1.248) Pub Date : 2020-02-28 W. Cao, H. D. Ng, J. H. S. Lee
The near-limit gaseous detonation behavior of three different methane–oxygen mixtures was investigated. Experiments were performed in transparent tubes of three different inner diameters (d). Due to the relatively large tube length l (\(\frac{l}{d} > 2500\) except \(\frac{l}{d} > 1000\) for the largest diameter), the tube was arranged in a spiral configuration for the convenience of testing. Photodiodes
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Addendum: An interface to provide the physical properties of blast waves generated by propane explosions Shock Waves (IF 1.248) Pub Date : 2020-04-10 J. M. Dewey
The paper by J.M. Dewey (Shock Waves 29(4):583–587, 2019) described the development of an Excel-based interface that provides the physical properties of blast waves generated by propane/oxygen explosions. The interface was developed using the data from a nominal 20 ton explosion of an assumed stoichiometric propane/oxygen mixture. Comparisons of data from the interface with measurements of small-scale
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Transient combustion phenomena in high-speed flows in ducts Shock Waves (IF 1.248) Pub Date : 2020-04-06 V. V. Vlasenko; V. A. Sabelnikov; S. S. Molev; O. V. Voloshchenko; M. A. Ivankin; S. M. Frolov
The problem of combustion stabilization in a duct with supersonic flow at the entrance is studied by means of numerical simulation, with the use of experimental data if available. The influence of the transient process of combustion development on the final flow structure is demonstrated. Four examples are considered and analyzed: oscillations of a pseudoshock with combustion in an asymmetric duct
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Experimental investigation of end-gas autoignition-to-detonation transition for an n-decane/O 2 /Ar mixture Shock Waves (IF 1.248) Pub Date : 2020-04-01 H. Quintens; C. Strozzi; R. Zitoun; M. Bellenoue
The transition between different combustion regimes is investigated experimentally for a stoichiometric argon-diluted n-decane/O2 mixture. The focus is put on the influence of initial temperature (T = 420–470 K) and pressure (P = 1.5–3 bar) on the regime transitions. Fast schlieren visualization (≥ 120 kHz) and high-speed pressure and temperature measurements are used to monitor the evolution of the
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Cellular detonation propagation and degeneration in bi-disperse gas suspensions of micron- and nano-sized aluminum particles Shock Waves (IF 1.248) Pub Date : 2020-03-27 S. A. Lavruk; A. V. Fedorov; T. A. Khmel
Cellular detonation flows in bi-disperse oxygen suspensions of micron-, submicron-, and nano-sized aluminum particles are studied numerically on the basis of the semiempirical model of detonation. The transition from diffusion-limited combustion of micron-sized particles to the kinetic combustion regime of nano-sized aluminum particles is taken into account. The influence of the particle size and the
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Effects of solid circular cylinders on the dynamics of the Richtmyer–Meshkov instability Shock Waves (IF 1.248) Pub Date : 2020-03-12 M. Al-Marouf; R. Samtaney
We discuss the effect on the transient dynamics of the Richtmyer–Meshkov instability due to small-scale perturbations introduced by a set of solid circular cylinders located along the material interface. The arrangement of the cylinders mimics (in a two-dimensional domain) the presence of the solid supporting grid wires used in the formation of the material interface in an experimental setup. The numerical
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Scaling of cylinder-generated shock-wave/turbulent boundary-layer interactions Shock Waves (IF 1.248) Pub Date : 2020-02-27 S. A. Lindörfer; C. S. Combs; P. A. Kreth; R. B. Bond; J. D. Schmisseur
Scaling parameters of shock-wave/turbulent boundary-layer interactions generated by a semi-infinite standing cylinder were explored in a combined numerical and experimental effort, consisting of Reynolds-averaged Navier–Stokes simulations and high-speed schlieren imaging. The primary interaction variable, the cylinder diameter (d), and a secondary interaction variable, the boundary-layer thickness
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Shock response of polymer-bonded copper powder Shock Waves (IF 1.248) Pub Date : 2020-02-25 A. C. Anastacio; C. Braithwaite; J. Kucera; E. Schmidova; J. Pachman
The shock response of a polymer-bonded copper powder was investigated by means of plate impact experiments in a gas gun (pressure range 1–8 GPa) and using in-contact explosive loading (pressures up to 37 GPa). Stress gauges were used to determine the material shock states in the planar impact, and the experimental data of shock and particle velocities (U, u) were fitted to a straight line giving a
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Flame front dynamics studies at deflagration-to-detonation transition in a cylindrical tube at low-energy initiation mode Shock Waves (IF 1.248) Pub Date : 2020-02-08 Y. A. Baranyshyn; P. N. Krivosheyev; O. G. Penyazkov; K. L. Sevrouk
The aim of this work was to study the dynamics of deflagration-to-detonation transition (DDT) following flame acceleration in a cylindrical tube. We combined high-speed video recordings of self-luminescence and traditional local flow measurements to study the DDT process in a stoichiometric acetylene–oxygen mixture with argon dilution and nitrogen dilution. Experiments were carried out in a cylindrical
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Experimental study of blast loading behind a building corner Shock Waves (IF 1.248) Pub Date : 2020-01-30 T. Gajewski; P. W. Sielicki
The paper presents unique blast experiments in reference to scientific literature and official standards. Experimental scenarios reflect a hypothetical realistic combat situation of a human being covered from a blast wave behind a rigid building corner. In the scenario assumed, the overpressure loads affect the lungs while the person is standing or the eardrums while the person is kneeling at the aiming
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StanShock : a gas-dynamic model for shock tube simulations with non-ideal effects and chemical kinetics Shock Waves (IF 1.248) Pub Date : 2020-01-01 K. Grogan; M. Ihme
A high-order, quasi-one-dimensional, reacting, compressible flow solver is developed to simulate non-ideal effects and chemical kinetics in shock tube systems. To this end, physical models for the thermoviscous boundary-layer development, area variation, gas interfaces, and reaction chemistry are considered. The model is first verified through simulations of steady isentropic nozzle flow, multi-species
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Heat-induced planar shock waves in supercritical fluids Shock Waves (IF 1.248) Pub Date : 2019-12-23 M. T. Migliorino; C. Scalo
We have investigated one-dimensional compression waves, produced by heat addition in quiescent and uniform initial conditions, in six different supercritical fluids, each taken in four states ranging from compressible pseudo-liquid fluid to ideal gas. Navier–Stokes simulations of a canonical semi-infinite domain flow problem, spanning five orders of magnitude of heating rate, are also carried out to
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Modeling mesoscale energy localization in shocked HMX, Part II: training machine-learned surrogate models for void shape and void–void interaction effects Shock Waves (IF 1.248) Pub Date : 2019-12-16 S. Roy; N. K. Rai; O. Sen; D. B. Hardin; A. S. Diggs; H. S. Udaykumar
Surrogate models for hotspot ignition and growth rates were presented in Part I (Nassar et al., Shock Waves 29(4):537–558, 2018), where the hotspots were formed by the collapse of single cylindrical voids. Such isolated cylindrical voids are idealizations of the void morphology in real meso-structures. This paper therefore investigates the effect of non-cylindrical void shapes and void–void interactions
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Expansion tube nozzle design using a parallel simplex algorithm Shock Waves (IF 1.248) Pub Date : 2019-12-14 P. Toniato; D. E. Gildfind; P. A. Jacobs; R. G. Morgan
A new hypersonic Mach 12 nozzle has been designed and manufactured for a large-scale expansion tube. The nozzle design goals were to produce a Mach 12 flow, with a core flow diameter of at least 300 mm and a maximum exit flow angle non-uniformity of less than \({2}^{\circ }\). The nozzle has been designed by coupling a RANS CFD solver with a parallel simplex algorithm to solve the computationally expensive
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Aerodynamic design of integrated propulsion–airframe configuration of a hybrid wing body aircraft Shock Waves (IF 1.248) Pub Date : 2019-12-05 M.-F. Liou; H. Kim; B. Lee; M.-S. Liou
A hybrid wing body (HWB) concept is being considered by NASA as a potential subsonic transport aircraft that meets aerodynamic, fuel, emission, and noise goals in the time frame beyond 2035. While the concept promises advantages over a conventional wing-and-tube aircraft, it poses unknowns and risks, thus requiring in-depth and broad assessments. Specifically, the configuration entails a tight integration
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Gaussian models for late-time evolution of two-dimensional shock–light cylindrical bubble interaction Shock Waves (IF 1.248) Pub Date : 2019-11-07 Y. Li; Z. Wang; B. Yu; B. Zhang; H. Liu
Two-dimensional shock–bubble interaction is an analogy of the steady three-dimensional jet flow in a scramjet. On the basis of Navier–Stokes simulations, a cylindrical bubble embedded with hydrogen surrounded by air was accelerated by a shock. The evolution can be divided into the lobe-emergence stage, the back-lobe suction stage, and the equilibrium stage. Based on the inhomogeneity between the hydrogen
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An apparatus for producing tunable, repeatable, hydrogen–oxygen-deflagrative blast waves Shock Waves (IF 1.248) Pub Date : 2019-10-28 T. Skinner; M. J. Hargather; J. Blackwood; M. Hays; M. Bangham
The Hydrogen Unconfined Combustion Test Apparatus (HUCTA) was designed and built to study the blast waves produced from unconfined hydrogen/oxygen deflagrations. The HUCTA uses evacuated balloons of up to 2 m in diameter which are filled with a combustible combination of gaseous hydrogen–oxygen mixtures. The well-mixed gases are ignited with an electric spark at the center of the sphere, resulting
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Simulation-driven design of experiments examining the large-scale, explosive dispersal of particles Shock Waves (IF 1.248) Pub Date : 2019-10-15 K. T. Hughes; S. Balachandar; A. Diggs; R. Haftka; N. H. Kim; D. Littrell
A series of six, large-scale tests were performed at the Eglin Air Force Base blastpad facility to serve as a validation benchmark for the explosive dispersal of particles. The series contained two baseline tests, one tungsten liner test, and three steel liner tests. Careful emphasis was placed on design of the experiments to allow ease of simulation, uncertainty quantification of experimental inputs
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Skew-symmetric splitting of high-order central schemes with nonlinear filters for computational aeroacoustics turbulence with shocks Shock Waves (IF 1.248) Pub Date : 2019-10-10 B. Sjögreen; H. C. Yee; A. A. Wray
A class of high-order nonlinear filter schemes by Yee et al. (J Comput Phys 150:199–238, 1999), Sjögreen and Yee (J Comput Phys 225:910–934, 2007), and Kotov et al. (Commun Comput Phys 19:273–300, 2016; J Comput Phys 307:189–202, 2016) is examined for long-time integrations of computational aeroacoustics (CAA) turbulence applications. This class of schemes was designed for an improved nonlinear stability
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Effect of duct aspect ratio on normal shock wave/boundary layer interaction Shock Waves (IF 1.248) Pub Date : 2019-10-10 S. Vaisakh; P. R. Namratha; T. M. Muruganandam
Experiments have been conducted in a supersonic rectangular duct (Mach 1.4), with a normal shock wave/boundary layer interaction. The duct is designed in a modular fashion so that its aspect ratio can be varied without a change in the flow geometry. The shock location, duct height, and Mach number are kept constant, while varying the aspect ratio. Conventional and inclined schlieren techniques have
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Gap-induced transition via oblique breakdown at Mach 6 Shock Waves (IF 1.248) Pub Date : 2019-10-05 Y. Xue; L. Wang; Z. J. Wang; S. Fu
It is well known that hypersonic boundary-layer transition is sensitive to a surface roughness since the roughness may either trigger an early transition or delay the transition. Hypersonic transition is still poorly understood as there are a very limited number of studies in the literature. In the present work, we conduct a computational study on the transition process of a hypersonic Mach 6 flow
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Measurement and numerical simulation of shock standoff distances over hypersonic spheres in CO 2 in a ballistic range Shock Waves (IF 1.248) Pub Date : 2019-10-01 D. Liao; S. Liu; J. Huang; H. Jian; A. Xie; Z. Wang
To gather test data of the nonequilibrium flow in CO2 and investigate the influence of the two-temperature nonequilibrium model on numerical simulations, measurements of shock standoff distances over hypersonic spheres in CO2 have been taken in the hypervelocity ballistic ranges of the Hypervelocity Aerodynamics Institute, China Aerodynamics Research and Development Center. Corresponding numerical
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