The propagation of detonation waves in non-ideal condensed-phase explosives confined by high sound-speed materials

2013 ◽  
Vol 25 (8) ◽  
pp. 086102 ◽  
Author(s):  
Stefan Schoch ◽  
Nikolaos Nikiforakis ◽  
Bok Jik Lee
Keyword(s):  
Condensed Phase ◽  
Sound Speed ◽  
Detonation Waves ◽  
Condensed Phase Explosives ◽  
High Sound

Asymptotic calculation of the dynamics of self-sustained detonations in condensed phase explosives

2012 ◽  
Vol 710 ◽  
pp. 166-194 ◽  
Author(s):  
J. A. Saenz ◽  
B. D. Taylor ◽  
D. S. Stewart
Keyword(s):  
Equation Of State ◽  
Euler Equations ◽  
Condensed Phase ◽  
Asymptotic Relation ◽  
Single Step ◽  
Detonation Waves ◽  
Normal Velocity ◽  
Exothermic Chemical Reaction ◽  
Detonation Shock ◽  
Condensed Phase Explosives

AbstractWe use the weak-curvature, slow-time asymptotics of detonation shock dynamics (DSD) to calculate an intrinsic relation between the normal acceleration, the normal velocity and the curvature of a lead detonation shock for self-sustained detonation waves in condensed phase explosives. The formulation uses the compressible Euler equations for an explosive that is described by a general equation of state with multiple reaction progress variables. The results extend an earlier asymptotic theory for a polytropic equation of state and a single-step reaction rate model discussed by Kasimov (Theory of instability and nonlinear evolution of self-sustained detonation waves. PhD thesis, University of Illinois Urbana-Champaign, Urbana, Illinois) and by Kasimov & Stewart (Phys. Fluids, vol. 16, 2004, pp. 3566–3578). The asymptotic relation is used to study the dynamics of ignition events in solid explosive PBX-9501 and in porous PETN powders. In the case of porous or powdered explosives, two composition variables are used to represent the extent of exothermic chemical reaction and endothermic compaction. Predictions of the asymptotic formulation are compared against those of alternative DSD calculations and against shock-fitted direct numerical simulations of the reactive Euler equations.

Well‐Posed Equations of States for Condensed‐Phase Explosives

2019 ◽  
Vol 45 (3) ◽  
pp. 374-386 ◽  
Author(s):  
Kibaek Lee ◽  
Alberto M. Hernández ◽  
D. Scott Stewart
Keyword(s):  
Condensed Phase ◽  
Condensed Phase Explosives ◽  
Well Posed

scholarly journals Forbidden line diagnostics of photoevaporative disc winds

2020 ◽  
Vol 496 (3) ◽  
pp. 2932-2945 ◽  
Author(s):  
G Ballabio ◽  
R D Alexander ◽  
C J Clarke
Keyword(s):  
Sound Speed ◽  
Central Star ◽  
High Energy ◽  
Emission Lines ◽  
Limiting Factor ◽  
Line Profiles ◽  
Gas Temperature ◽  
Characteristic Emission ◽  
Extreme Uv ◽  
High Sound

ABSTRACT Photoevaporation driven by high-energy radiation from the central star plays an important role in the evolution of protoplanetary discs. Photoevaporative winds have been unambiguously detected through blue-shifted emission lines, but their detailed properties remain uncertain. Here we present a new empirical approach to make observational predictions of these thermal winds, seeking to fill the gap between theory and observations. We use a self-similar model of an isothermal wind to compute line profiles of several characteristic emission lines (in particular the [Ne ii] line at 12.81 μm, and optical forbidden lines such as [O i] 6300 Å and [S ii] 4068/4076 Å), studying how the lines are affected by parameters such as the gas temperature, disc inclinations, and density profile. Our model successfully reproduces blue-shifted lines with $v_{\rm peak} \lesssim 10$ km s−1, which decrease with increasing disc inclination. The line widths increase with increasing disc inclinations and range from $\Delta v\sim 15\text{ to }30$ km s−1. The predicted blue-shifts are mostly sensitive to the gas sound speed (and therefore the temperature). The observed [Ne ii] line profiles are consistent with a thermal wind and point towards a relatively high sound speed, as expected for extreme-UV photoevaporation. However, the observed [O i] line profiles require lower temperatures, as expected in X-ray photoevaporation, and show a wider scatter that is difficult to reconcile with a single wind model; it seems likely that these lines trace different components of a multiphase wind. We also note that the spectral resolution of current observations remains an important limiting factor in these studies, and that higher resolution spectra are required if emission lines are to further our understanding of protoplanetary disc winds.

Equation of state and reaction rate for condensed-phase explosives

2005 ◽  
Vol 98 (5) ◽  
pp. 053514 ◽  
Author(s):  
B. L. Wescott ◽  
D. Scott Stewart ◽  
W. C. Davis
Keyword(s):  
Equation Of State ◽  
Condensed Phase ◽  
Reaction Rate ◽  
Condensed Phase Explosives

An Eulerian algorithm for coupled simulations of elastoplastic-solids and condensed-phase explosives

2013 ◽  
Vol 252 ◽  
pp. 163-194 ◽  
Author(s):  
Stefan Schoch ◽  
Kevin Nordin-Bates ◽  
Nikolaos Nikiforakis
Keyword(s):  
Condensed Phase ◽  
Condensed Phase Explosives

Detection of condensed-phase explosives via laser-induced vaporization, photodissociation, and resonant excitation

2008 ◽  
Vol 47 (31) ◽  
pp. 5767 ◽  
Author(s):  
C. M. Wynn ◽  
S. Palmacci ◽  
R. R. Kunz ◽  
K. Clow ◽  
M. Rothschild
Keyword(s):  
Condensed Phase ◽  
Resonant Excitation ◽  
Condensed Phase Explosives
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