Abstract: We report experimental studies on the initiation of detonations by hypervelocity projectiles in hydrogen-oxygen-nitrogen mixtures. The experimental facility T5 at Caltech was modified to launch 25-mm diameter projectiles at speeds around 3000 m/s. Flow visualization and pressure measurements are reported for several mixture conditions. A clear transition between shockinduced combustio...

The hydrodynamic stability of deflagration and detonation bubbles for a first order electroweak and QCD phase transition has been discussed recently with the suggestion that detonations are stable. We examine here the case of a detonation more carefully. We find that in front of the bubble wall perturbations do not grow with time, but behind the wall modes exist which grow exponentially. We bri...

The benefits of using insensitive high explosives (IHE) like PBX 9502 (9502) have been well documented [1]. These desirable features come at a price. The reaction zone is longer for IHEs, thus making them more nonideal. In real world applications, this translates into significant performance problems, such as problems with detonation wave spreading. The speed of detonation propagation is affect...

The linear stability of a planar detonation wave with a three-step chain-branching reaction is studied by a normal mode approsch. The reaction model consists of a chain-initiation step and a chain-branching step governed by Arrhenius kinetics, with a chain-termination step which is independent of temperature. It mimics the essential reaction dynamics of a real chain-branching chemical system. T...

The propagation speed of a shock or detonation wave in a shock or detonation tube is usually determined by a time-of-flight method by dividing the distance between two transducers with the propagation time of the disturbance signal. Some arbitrariness is inherent in determining the propagation time by this method. A new method based on Haar and Morlet wavelet transforms is reported. The method ...

This computational study examines transient, reactive compressible flow phenomena associated with the pulse detonation wave engine. The PDWE is an intermittent combustion engine that relies on unsteady detonation wave propagation for combustion and compression elements of the propulsive cycle. The present computations focus on high order numerical simulations of the generic PDWE configuration w...

It has long been a standard practice to neglect diffusive effects in stability analyses of detonation waves. Here, with the principal aim of quantifying the impact of these oft-neglected effects on the stability characteristics of such waves, we use numerical Evans-function techniques to study the (spectral) stability of viscous strong detonation waves—particular traveling-wave solutions of the...

We sampled residues from high-order and low-order blow-in-place detonations of mortars and projectiles filled with Composition B (Comp B), a TNT and RDX mixture. Our goals were to (1) characterize the types of explosive particles, (2) estimate the explosive 'footprint' for different munitions, and (3) estimate the mass of Comp B remaining after each detonation. The aerial deposition of Comp B p...

A nonlinear integral-differential equation describing the cellular front of an overdriven detonation is obtained by an analysis carried out in the neighborhood of the instability threshold. The analysis reveals both an unusual mean streaming motion, resulting from the rotational part of the oscillatory flow, and pressure bursts generated by the crossover of cusps representative of Mach stems pr...

T o address the hazards to civilians, recent landmine systems have incorporated command detonation by remote operator and self-destruct capabilities (see the “Landmines through the Ages” sidebar). However, these additions didn’t let the mines adaptively counter breach attempts and might have actually increased the need to monitor mine location to allow command detonation. Nor did they allow ope...