Experiments on the interaction of a pair of cylindrical weak blast waves in air

Abstract

Abstract. This paper reports the results of experiments and computations on the interaction of a pair of cylindrical blast waves in air. The waves were generated by exploding wires, and both symmetrical and unsymmetrical interactions were observed. The experimental data includes schlieren photographs of the wave interactions, their radii, shock Mach number and pressure versus time, as well as various cross plots and data on the shock regular/irregular interaction transition condition. The flow fields were computed with the help of the "Total Variation Diminishing'' (TVD) method, and appear to represent the experimental results reasonably well. Some attention is also given to the blast scaling laws of the type discussed by Sakurai (1965) and Oshima (1960).

GSD models for blast propagation]{Two-dimensional geometrical shock dynamics for blast wave propagation and post-shock flow effects

“…To evaluate the PGSD model for the application of two interacting blast waves, a symmetric setup of two cylindrical weak blast waves were simulated using a Lagrangian framework. The current work is compared to the results obtained previously through numerical simulations [10] and experiments [36].…”

“…Therefore, by comparing the post-shock flow effects from the two models and analyzing how their resulting blast behaviors differ, a conclusion can be made here that the level of the completeness of the post-shock flow term θ w Fig. 4 Schematic illustration of the experiments of Higashino et al [36] in which the exploding wire centers, represented by red stars, are located 60 mm apart from each other. The wedge angle is represented by θw.…”

“…The work by Higashino et al [36] consisted of experiments in which two cylindrical blast waves were generated simultaneously by rapidly discharging a high voltage through two thin metal wires. The wires explode as a result of the applied voltage and two cylindrical shock waves are formed.…”

“…The initial two-blast front was discretized with five particles per degree, i.e., ∆s ≈ 0.2 mm for the copper and ∆s ≈ 0.18 mm for the nichrome wire case. A second set of initial conditions, I.C.2., were introduced, this time based on the experimental results from Higashino et al's work [36] in which von Neumann's detachment theory [38] was used to determine the initial conditions. The second set of initial conditions, I.C.2., were determined to be [M 0 = 1.25, r 0 = 42.83 mm] and [M 0 = 1.50, r 0 = 45.96 mm] for the copper and nichrome wires, respectively.…”

Viscous jetting and Mach stem bifurcation in shock reflections: experiments and simulations

“…Boundary layers on the reflecting surface change the effective wedge angle (Hornung 1985;Ben-Dor 2007) and cause the forward jet to oscillate (Vasilev et al 2004;Shi et al 2017). While most simulations use free-slip boundaries, the few experiments (Smith 1959;Henderson & Lozzi 1975;Higashino, Henderson & Shimizu 1991;Barbosa & Skews 2002) performed with free-slip surfaces were focused on the transition from regular to irregular reflection. Shock reflections in detonations happen on a symmetry boundary, where boundary layers are absent, and there is a need for experiments to explore jetting under these conditions.…”