When describing the deflagration-to-detonation transition in solid granular explosives mixed with gaseous products of combustion, a well-developed two-phase mixture model is compressible Baer-Nunziato (BN) flows containing and gas phases. As this numerically simulated by conservative Godunov-type scheme, spurious oscillations are likely to generate from porosity interfaces, may result average p...

This study describes a methodology and gives analyses to determine the steady propagation speed of a projectile fired into a gaseous mixture of fuel and oxidizer. For tractability, the steady supersonic flow of an inviscid calorically perfect ideal reacting gas with high activation energy over a symmetric double wedge, unconfined by a cowl, is considered. Propagation speeds are found which give...

An algorithm was developed that uses measured isotopic ratios from fission product residue following the detonation of a high-enriched uranium nuclear weapon to compute the original attributes of the nuclear material used in the device. The specific attributes assessed are the uranium isotopics (considering U, U, U, and U) and the type of enrichment process used to create the material (e.g., ga...

The aim of the work performed in the current contract is to assess the accuracy of potential modelling techniques applied to the formation of Deflagration to Detonation (DDT) kernels in mixtures of hydrocarbons with air. The application area is of direct relevance to the transition to detonation in pulsed detonation engines featuring premixed gases. The latter technology is currently pursued at...

Context. A promising model for normal Type Ia supernova (SN Ia) explosions are delayed detonations of Chandrasekhar-mass white dwarfs, in which the burning starts out as a subsonic deflagration and turns at a later phase of the explosion into a supersonic detonation. The mechanism of the underlying deflagration-to-detonation transition (DDT) is unknown in detail, but necessary conditions have b...

It is possible to objectively determine whether a detona tion can propagate in a given geometry (volume shape and size, obstacle configuration, degree of confinement) for a given mixture composition (concentrations of hydrogen, air and steam); this is done by conservatively equating the detonation propaga tion criteria with the criteria for transition from deflagration to detonation. This paper...

Numerical simulations can be the key to the thorough understanding of the multi-dimensional nature of transient detonation waves. But the accurate approximation of realistic detonations is extremely demanding, because a wide range of different scales need to be resolved. This paper describes an efficient simulation strategy based on a generic implementation of a blockstructured dynamically adap...

We speculate that the universe is filled with stars composed of electromagnetic and dilaton fields. We calculate soliton-like solutions of these fields and show that their energy can be converted into a relativistic plasma in an explosive way whioch produces strong gamma-ray bursts observed in the universe. The conversion proceeds as in classical detonation theory by a relativistic self-similar...

Experimental images of propagating detonation waves provide lead shock velocity measurements through the cell cycle. We examine the issue of local decoupling of the shock and reaction front using these data. In highly unstable mixtures with high reduced activation energy, experimental images and analysis suggest that local decoupling occurs at the end of the cell cycle. Regions of high fluoresc...