scholarly journals Numerical simulation of detonation propagation in PETN at arbitrary intitial density by simple model

2012 ◽  
Author(s):  
Shiro Kubota ◽  
Tei Saburi ◽  
Yuji Ogata ◽  
Kunihito Nagayama
Keyword(s):  
Numerical Simulation ◽  
Simple Model ◽  
Detonation Propagation

Gaseous detonation propagation in a bifurcated tube

2008 ◽  
Vol 599 ◽  
pp. 81-110 ◽  
Author(s):  
C. J. WANG ◽  
S. L. XU ◽  
C. M. GUO
Keyword(s):  
Numerical Simulation ◽  
Detonation Wave ◽  
Mach Reflection ◽  
Initial Pressure ◽  
Gaseous Detonation ◽  
Recirculation Region ◽  
Horizontal Branch ◽  
Regular Reflection ◽  
Detonation Propagation ◽  
Wall Geometry

Gaseous detonation propagation in a bifurcated tube was experimentally and numerically studied for stoichiometric hydrogen and oxygen mixtures diluted with argon. Pressure detection, smoked foil recording and schlieren visualization were used in the experiments. Numerical simulation was carried out at low initial pressure (8.00kPa), based on the reactive Navier–Stokes equations in conjunction with a detailed chemical reaction model. The results show that the detonation wave is strongly disturbed by the wall geometry of the bifurcated tube and undergoes a successive process of attenuation, failure, re-initiation and the transition from regular reflection to Mach reflection. Detonation failure is attributed to the rarefaction waves from the left-hand corner by decoupling leading shock and reaction zones. Re-initiation is induced by the inert leading shock reflection on the right-hand wall in the vertical branch. The branched wall geometry has only a local effect on the detonation propagation. In the horizontal branch, the disturbed detonation wave recovers to a self-sustaining one earlier than that in the vertical branch. A critical case was found in the experiments where the disturbed detonation wave can be recovered to be self-sustaining downstream of the horizontal branch, but fails in the vertical branch, as the initial pressure drops to 2.00kPa. Numerical simulation also shows that complex vortex structures can be observed during detonation diffraction. The reflected shock breaks the vortices into pieces and its interaction with the unreacted recirculation region induces an embedded jet. In the vertical branch, owing to the strength difference at any point and the effect of chemical reactions, the Mach stem cannot be approximated as an arc. This is different from the case in non-reactive steady flow. Generally, numerical simulation qualitatively reproduces detonation attenuation, failure, re-initiation and the transition from regular reflection to Mach reflection observed in experiments.

scholarly journals A Simple Model for the Quantum Hydrodynamic Simulation of Electron Transport in Quantum Confined Structures in the Presence of Vortices

VLSI Design ◽  
2001 ◽  
Vol 13 (1-4) ◽  
pp. 237-244 ◽  
Author(s):  
J. R. Barker
Keyword(s):  
Numerical Simulation ◽  
Simple Model ◽  
Quantum Transport ◽  
Hydrodynamic Simulation ◽  
Spatially Correlated ◽  
Non Local ◽  
Quantum Hydrodynamic ◽  
String Representation ◽  
Ray Trajectories ◽  
Classical Particles

It is demonstrated that the ballistic quantum transport properties of an open quantum dot may be described by an ensemble of spatially correlated virtual classical particles moving within self-avoiding strings. The string paths correspond to ray trajectories. The strings exhibit the necessary properties of self-avoidance, interference and the non-local condition ∮mv · dr=nh. The formalism suggests that numerical simulation of quantum flows may be constructed ab initio by using the string representation.

scholarly journals A simple model for growth of a planar hydrogenated carbon cluster under interstellar or circumstellar conditions

1997 ◽  
Vol 180 ◽  
pp. 268-268
Author(s):  
G. Pascoli
Keyword(s):  
Numerical Simulation ◽  
Simple Model ◽  
Amorphous Carbon ◽  
Carbon Cluster ◽  
Carbon Clusters ◽  
Hydrogen Atoms ◽  
Simulation Code ◽  
Carbon Chains ◽  
Physico Chemical ◽  
Open Question

The physico-chemical origin of the hydrogenated carbon clusters (cumulenes, PAHs, graphite or amorphous carbon) in space is still an open question. We have worked out a numerical simulation code in order to build up planar (graphite-like) carbon clusters. We assume that hydrogen atoms can fix on the carbon skeleton following a random process allowing for H2 formation. The structures we have found are very complex. In a given cluster, several molecular entities can simultaneously be present: (sp2) carbon chains, rings or compact formations (aromatic structures or small PAHs). We argue that these very contorted hydrogenated structures could be ubiquitous in the interstellar medium, in carbon-rich circumstellar regions and in PNe.

Numerical Simulation of the Influence of Weld Model on the Response of Stiffened Plates under Blast Loading

2012 ◽  
Vol 204-208 ◽  
pp. 943-948
Author(s):  
Xin Ming Zhu ◽  
Hao Zhan ◽  
Zhi Gang Jiang
Keyword(s):  
Numerical Simulation ◽  
Simple Model ◽  
Failure Modes ◽  
Blast Loading ◽  
Stiffened Plates ◽  
Engineering Structures ◽  
Critical Charge ◽  
Stiffened Structures ◽  
Good Agreement

Stiffened plates are used in a wide variety of engineering structures. Based on the published experiments, two kinds of weld models were established in simulation and the influence of weld model on the response of stiffened plates under blast loading was analyzed. The results show that the deflections and failure modes of stiffened plates from simulation are in good agreement with those from experiments, and that the weld model has little influence on the deformation and the critical charge of the plates. A simple model can be used for analyzing the large stiffened structures under blast loading.

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