A Systematic Exposition of the Conservation Equations for Blast Waves

1971 ◽  
Vol 38 (4) ◽  
pp. 783-794 ◽  
Author(s):  
A. K. Oppenheim ◽  
E. A. Lundstrom ◽  
A. L. Kuhl ◽  
M. M. Kamel
Keyword(s):  
Flow Field ◽  
Blast Wave ◽  
Blast Waves ◽  
Lagrangian System ◽  
Conservation Equations ◽  
Time Profiles ◽  
Wave Coordinates ◽  
Wave Phenomena ◽  
Eulerian System ◽  
Proper Account

In order to provide a rational background for the analysis of experimental observations of blast wave phenomena, the conservation equations governing their nonsteady flow field are formulated in a general manner, without the usual restrictions imposed by an equation of state, and with proper account taken, by means of source terms, of other effects which, besides the inertial terms that conventionally dominate these equations, can affect the flow. Taking advantage of the fact that a blast wave can be generally considered as a spatially one-dimensional flow field whose nonsteady behavior can be regarded, consequently, as a function of just two independent variables, two generalized blast wave coordinates are introduced, one associated with the front of the blast wave and the other with its flow field. The conservation equations are accordingly transformed into this coordinate system, acquiring thereby a comprehensive character, in that they refer then to any frame of reference, being applicable, in particular, to problems involving either space or time profiles of the gas-dynamic parameters in the Eulerian system, or time profiles in the Lagrangian system.

Blast waves in dusty gases

1987 ◽  
Vol 414 (1846) ◽  
pp. 197-219 ◽  
Keyword(s):  
Flow Field ◽  
Wave Front ◽  
Blast Wave ◽  
Spherical Layer ◽  
Blast Waves ◽  
Solid Particles ◽  
Dust Particles ◽  
Spatial Density ◽  
Maximum Pressure ◽  
Sharp Maximum

The conservation equations for the flow field developed behind a spherical blast wave propagating into a dusty medium (gas seeded with small uniformly distributed solid particles) are formulated and solved numerically by using the random choice method. The solution was carried out for the following three cases: (1) the dust is uniformly distributed outside the exploding spherical diaphragm; (2) the dust is uniformly distributed inside the exploding spherical diaphragm; (3) the dust is uniformly distributed inside a spherical layer located outside the exploding spherical diaphragm. The solutions obtained were compared with a similar pure-gas case. It was found that the dust presence weakens the blast wave, i. e. the gas velocity, temperature and pressure immediately behind the blast-wave front were lower than those obtained in a similar pure-gas case. The presence of dust changed the flow field behind the blast wave. The typical blast-wave pressure signature (i. e. a monotonic reduction in the pressure after the jump across the blast-wave front) changed to a different shape. Now the pressure increases after the blast-wave front until it reaches a maximum value followed by a monotonic pressure reduction. The maximum pressure is attained between the blast-wave front and the contact surface. Higher values of total pressure are obtained in the dusty gas case. The initial uniform spatial distribution of the dust particles changed into a bell-shaped pattern with a pronounced peak. The development of the sharp maximum in the dust spatial-density distribution might be of interest in assessing the effects of atmospheric nuclear explosions.

The flow field induced by spherical blast waves propagating into perfect and imperfect dusty gases

1989 ◽  
Vol 41 (2) ◽  
pp. 355-380 ◽  
Author(s):  
Z. Rakib ◽  
M. Mond ◽  
G. Ben-Dor ◽  
O. Igra
Keyword(s):  
Flow Field ◽  
Blast Wave ◽  
Gaseous Phase ◽  
Initial Energy ◽  
Blast Waves ◽  
Real Gas ◽  
Present Solution ◽  
Real Gas Effects ◽  
Loading Ratio ◽  
Dust Loading

The flow fields induced by spherical blast waves propagating into dusty gases are investigated numerically. In the case of a moderate blast wave the gaseous phase is assumed to be perfect, while for strong blast waves real-gas effects are accounted for. The effects of the dust loading ratio and the initial energy used to generate the blast on the suspension properties are investigated and discussed in detail. Owing to the fact that the physics involved inside the exploding charge is very complicated, the present solution is appropriate for simulating the flow induced by the blast wave outside the exploding sphere only.

scholarly journals In silico investigation of biomechanical response of a human subjected to primary blast

2021 ◽  
Author(s):  
Sunil Sutar ◽  
Shailesh Ganpule
Keyword(s):  
White Matter ◽  
Blast Wave ◽  
Rotational Motion ◽  
Blast Waves ◽  
Primary Blast ◽  
Body Model ◽  
The Past ◽  
Biomechanical Response ◽  
The Brain ◽  
Full Body

The response of the brain to the explosion induced primary blast waves is actively sought. Over the past decade, reasonable progress has been made in the fundamental understanding of bTBI using head surrogates and animal models. Yet, the current understanding of how blast waves interact with the human is in nascent stages, primarily due to lack of data in humans. The biomechanical response in human is critically required so that connection to the aforementioned bTBI models can be faithfully established. Here, using a detailed, full-body human model, we elucidate the biomechanical cascade of the brain under a primary blast. The input to the model is incident overpressure as achieved by specifying charge mass and standoff distance through ConWep. The full-body model allows to holistically probe short- (<5 ms) and long-term (200 ms) brain biomechanical responses. The full-body model has been extensively validated against impact loading in the past. In this work, we validate the head model against blast loading. We also incorporate structural anisotropy of the brain white matter. Blast wave human interaction is modeled using a conventional weapon modeling approach. We demonstrate that the blast wave transmission, linear and rotational motion of the head are dominant pathways for the biomechanical loading of the brain, and these loading paradigms generate distinct biomechanical fields within the brain. Blast transmission and linear motion of the head govern the volumetric response, whereas the rotational motion of the head governs the deviatoric response. We also observe that blast induced head rotation alone produces a diffuse injury pattern in white matter fiber tracts. Lastly, we find that the biomechanical response under blast is comparable to the impact event. These insights will augment laboratory and clinical investigations of bTBI and help devise better blast mitigation strategies.

Blast Wave Mitigation from the Straight Tube by Using Water Part II - Numerical Simulation

2018 ◽  
Vol 910 ◽  
pp. 78-83 ◽  
Author(s):  
Yuta Sugiyama ◽  
Tomotaka Homae ◽  
Kunihiko Wakabayashi ◽  
Tomoharu Matsumura ◽  
Yoshio Nakayama
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Energy Transfer ◽  
Numerical Simulations ◽  
Blast Wave ◽  
Blast Waves ◽  
Straight Tube ◽  
Water Interface ◽  
Effect Of Water ◽  
Air Water Interface

This paper investigates explosions in a straight square tube in order to understand the mitigation effect of water on blast waves that emerge outside. Numerical simulations are used to assess the effect of water that is put inside the tube. The water reduces the peak overpressure outside, which agrees well with the experimental data. The increases in the kinetic and internal energies of the water are estimated, and the internal energy transfer at the air/water interface is shown to be an important factor in mitigating the blast wave in the present numerical method.

scholarly journals Vectorial dispersive shock waves in optical fibers

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
J. Nuño ◽  
C. Finot ◽  
G. Xu ◽  
G. Millot ◽  
M. Erkintalo ◽  
...  
Keyword(s):  
Shock Waves ◽  
Fiber Optics ◽  
Optical Fibers ◽  
Continuous Wave ◽  
Blast Waves ◽  
Nonlinear Fiber Optics ◽  
Nonlinear Phase ◽  
Perfect Fluids ◽  
Bose Einstein ◽  
Wave Phenomena

Abstract Dispersive shock waves are a universal phenomenon encountered in many fields of science, ranging from fluid dynamics, Bose-Einstein condensates and geophysics. It has been established that light behaves as a perfect fluid when propagating in an optical medium exhibiting a weakly self-defocusing nonlinearity. Consequently, this analogy has become attractive for the exploration of dispersive shock wave phenomena. Here, we observe of a novel class of vectorial dispersive shock waves in nonlinear fiber optics. Analogous to blast-waves, identified in inviscid perfect fluids, vectorial dispersive shock waves are triggered by a non-uniform double piston imprinted on a continuous-wave probe via nonlinear cross-phase modulation, produced by an orthogonally-polarized pump pulse. The nonlinear phase potential imparted on the probe results in the formation of an expanding zone of zero intensity surrounded by two repulsive oscillating fronts, which move away from each other with opposite velocities.

scholarly journals GRB 030329: 3 years of radio afterglow monitoring

2007 ◽  
Vol 365 (1854) ◽  
pp. 1241-1246 ◽  
Author(s):  
A.J van der Horst ◽  
A Kamble ◽  
R.A.M.J Wijers ◽  
L Resmi ◽  
D Bhattacharya ◽  
...  
Keyword(s):  
Blast Wave ◽  
Gamma Ray ◽  
Ambient Medium ◽  
Low Frequency ◽  
Blast Waves ◽  
Physical Parameters ◽  
Late Time ◽  
Wave Band ◽  
Radio Telescopes ◽  
Relativistic Phase

Radio observations of gamma-ray burst (GRB) afterglows are essential for our understanding of the physics of relativistic blast waves, as they enable us to follow the evolution of GRB explosions much longer than the afterglows in any other wave band. We have performed a 3-year monitoring campaign of GRB 030329 with the Westerbork Synthesis Radio Telescopes and the Giant Metrewave Radio Telescope. Our observations, combined with observations at other wavelengths, have allowed us to determine the GRB blast wave physical parameters, such as the total burst energy and the ambient medium density, as well as to investigate the jet nature of the relativistic outflow. Further, by modelling the late-time radio light curve of GRB 030329, we predict that the Low-Frequency Array (30–240 MHz) will be able to observe afterglows of similar GRBs, and constrain the physics of the blast wave during its non-relativistic phase.

scholarly journals Vortex structures and turbulence emerging in a supernova 1987a configuration: Interactions of “complex” blast waves and cylindrical/spherical bubbles

2003 ◽  
Vol 21 (3) ◽  
pp. 471-477 ◽  
Author(s):  
SHUANG ZHANG ◽  
NORMAN J. ZABUSKY ◽  
KATSUNOBU NISHIHARA
Keyword(s):  
Blast Wave ◽  
Flow Instability ◽  
Supernova Explosion ◽  
Blast Waves ◽  
High Density ◽  
Supernova 1987A ◽  
Planar Shock ◽  
Spherical Bubbles ◽  
Inhomogeneous Flow ◽  
Piecewise Parabolic

We examine the interaction of both cylindrical and spherical bubbles (2D) and acomplexblast wave, which consists of an approaching shock/contact discontinuity/shock (Kanget al., 2001a, 2001b). Such configurations may arise following a supernova explosion, for example, SN 1987A, where a complex blast wave is presently approaching a high density “circumstellar ring” (CR) (Borkowskiet al., 1997). Using simulations with the piecewise parabolic method algorithm (Colella & Woodward, 1984), we emphasize the appearance of vortex bilayers, vortex projectiles, and turbulent domains on the downstream and upstream sides of the bubble. We believe that the interfacial deformation of the CR is associated with astrong blast-wave driven accelerated inhomogeneous flow instabilityin ahigh densitymedium and thus will have a different character than the more common planar shock-driven Richtmyer–Meshkov instability.

Shock Tube Design for High Fidelity Blast Wave Simulation

2015 ◽  
Author(s):  
Christopher Ostoich ◽  
Mark Rapo ◽  
Brian Powell ◽  
Humberto Sainz ◽  
Philemon Chan
Keyword(s):  
Shock Tube ◽  
Blast Wave ◽  
Laboratory Data ◽  
Blast Waves ◽  
High Fidelity ◽  
Ongoing Research ◽  
Wave Simulation ◽  
Blast Overpressure ◽  
Blast Exposure ◽  
Significant Pathway

Traumatic brain injury (TBI) has been recognized as the signature wound of the current conflicts and it has been hypothesized that blast overpressure can contribute a significant pathway to TBI. As such, there are many ongoing research efforts to understand the mechanism to blast induced TBI, which all require blast testing using physical and biological surrogates either in the field or in the laboratory. The use of shock tubes to generate blast-like pressure waves in a laboratory can effectively produce the large amounts of data needed for research into blast induced TBI. A combined analytical, computational, and experimental approach was developed to design an advanced shock tube capable of generating high quality out-of-tube blast waves. The selected tube design was fabricated and laboratory tests at various blast wave levels were conducted. Comparisons of tube-generated laboratory data with explosive-generated field data indicated that the shock tube could accurately reproduce blast wave loading on test surrogates. High fidelity blast wave simulation in the laboratory presents an avenue to rapidly and inexpensively generate the large volumes of data necessary to validate and develop theories linking blast exposure to TBI.

An Application of Discontinuous Galerkin Method for Blast Wave Simulations

2010 ◽  
Author(s):  
Emre Alpman
Keyword(s):  
Galerkin Method ◽  
Discontinuous Galerkin ◽  
Blast Wave ◽  
Finite Volume ◽  
Discontinuous Galerkin Method ◽  
Numerical Solutions ◽  
Blast Waves ◽  
Strong Discontinuities ◽  
Runge Kutta ◽  
Volume Method

An implementation of Runge-Kutta Discontinuous Galerkin method to an in-house computational fluid dynamics code capable of simulating blast waves was performed. The resultant code was tested for two shock tube problems with moderately and extremely strong discontinuities. Numerical solutions were compared with predictions of a finite volume method and exact solutions. It was observed that when there are extreme discontinuities in the flowfield, as in the case of blast waves, the limiter adopted for solution clearly affects the overall quality of the predictions. An alternative limiting technique was proposed and tested to improve the results obtained. Blast wave predictions using Runge-Kutta Discontinuous Galerkin method with the alternative limiting technique yielded slightly stronger and faster moving shock waves compared to finite volume solutions.

Blast-wave propagation in a spray

1978 ◽  
Vol 88 (4) ◽  
pp. 641-657 ◽  
Author(s):  
T. H. Pierce
Keyword(s):  
Gas Phase ◽  
Blast Wave ◽  
Wave Structure ◽  
Blast Waves ◽  
Decay Rates ◽  
Liquid Droplets ◽  
Two Phase ◽  
Number Range ◽  
Reactive Liquid ◽  
Particle Velocities

A first-order analysis is presented for the propagation of a blast wave through a dilute spray of non-reactive liquid droplets that are suspended in a non-reactive gas-phase carrier. The analysis permits straightforward computation of decay rates and internal wave structure for wave strengths in the approximate Mach number range 4 ≤ Ms ≤ 15, and loading factors (mass of spray per unit mass of carrier) less than about 0·4. The droplets must be sufficiently small to completely change phase in a distance behind the shock that is at all times negligible compared with the wave radius. Representative calculations are presented and discussed. These show more rapid decay rates and higher pressures, densities, and particle velocities in two-phase blast waves when compared against equivalent gas-phase blast waves. A simplification of the analysis for the regime of higher wave Mach numbers (strong waves) is also given, which for that case allows direct algebraic calculation of early wave characteristics.

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