Obtaining a rapid deflagration-to-detonation transition (DDT) within short smooth tube is challenging task. Here, an unconventional means of flame acceleration propagating upstream in subsonic and supersonic mixtures was introduced to acquire speedy DDT. The Navier–Stokes equations with adaptive mesh refinement technique detailed hydrogen–air chemistry reaction mechanism 11 species 27 steps were utilized resolve the entire DDT characteristics. effect initial Mach number on revealed...

Structured adaptive mesh refinement (SAMR) techniques can enable cutting-edge simulations of problems governed by conservation laws. Focusing on the strictly hyperbolic case, these notes explain all algorithmic and mathematical details a technically relevant implementation tailored for distributed memory computers. An overview background commonly used finite volume discretizations gas dynamics is included typical benchmarks to quantify accuracy performance dynamically code are discussed....

Numerical simulation can be key to the understanding of multidimensional nature transient detonation waves. However, accurate approximation realistic detonations is demanding as a wide range scales needs resolved. This paper describes successful solution strategy that utilizes logically rectangular dynamically adaptive meshes. The hydrodynamic transport scheme and treatment nonequilibrium reaction terms are sketched. A ghost fluid approach integrated into method allow for embedded...

In detonation engines and accidental explosions, a may propagate in an inhomogeneous mixture with non-uniform reactant concentration. this study, one- two-dimensional simulations are conducted for propagation hydrogen/oxygen/nitrogen mixtures periodic sinusoidal or square wave distribution of the The objective is to assess properties such mixtures. Specifically, quenching reinitiation, cellular structure, cell size speed deficit investigated. It found that there exists critical amplitude...

A virtual test facility (VTF) for studying the three-dimensional dynamic response of solid materials subject to strong shock and detonation waves has been constructed as part research program Center Simulating Dynamic Response Materials at California Institute Technology. The compressible fluid flow is simulated with a Cartesian finite volume method treating an embedded moving body, while Lagrangian element scheme employed describe structural hydrodynamic pressure loading. temporal splitting...

Abstract An experimental and computational investigation of the unsteady separation behaviour two spheres in Mach-4 flow is carried out. The spherical bodies, initially contiguous, are released with negligible relative velocity thereafter fly freely according to aerodynamic forces experienced. In experiments performed a supersonic Ludwieg tube, nylon suspended test section by weak threads which detached arrival flow. subsequent sphere motions structures recorded using high-speed (13 kHz)...

The extension to the split-step Fourier method (SSFM) for Schrödinger-type pulse propagation equations that we propose in this article is designed with accurate simulation of pulses femto-second regime single-mode communication fibers mind. We show via an appropriate operator splitting scheme, Kerr nonlinearity and self-steepening stimulated Raman scattering terms can be combined into a single sub-step consisting inhomogeneous quasilinear first-order hyperbolic system real-valued quantities...

A large-eddy simulation is conducted to investigate the transient structure of an unstable detonation wave in two dimensions and evolution intrinsic hydrodynamic instabilities. The dependency on grid resolution investigated, structures obtained by are compared with predictions from solving Euler Navier–Stokes equations directly. results indicate that predict irregular agreement experimental observations vorticity generation dissipation small scale should be taken into account. Thus, high...

The main objective of this work is to comprehensively provide a fundamental understanding the entire process flame-pressure wave interactions with end-gas autoignition and detonation development in confined chamber by two-dimensional numerical simulations stoichiometric hydrogen/air mixture. flame dynamics, pressure propagation, its structure evolution, together mechanism end gas, are analyzed detail. Six stages, including spherical flame, finger skirt touching sidewalls, interactions,...

Hypersonic flows involving two or more bodies travelling in close proximity to one another are encountered several important situations. The present work seeks explore aspect of the resulting flow problem by investigating forces experienced a secondary body when it is within domain influence primary at hypersonic speeds. An analytical methodology based on blast wave analogy developed and used predict force coefficients for simple geometries both three dimensions. When entirely inside shocked...