Terminal velocity of liquids and granular materials dispersed by a high explosive

Explosively driven hierarchical particle jetting

“…Extensive studies, the bulk of which are field tests using cylindrical or spherical geometries, agree on some fundamental features of the particle jetting phenomenon (Milne et al, 2010;Ripley et al, 2011;Milne et al, 2014;Frost et al, 2017a;Loiseau et al, 2018). Specifically, the particle jetting becomes recognizable during the shock interaction timescale and occurs in the absence of inner and outer casings (Milne et al, 2010;Ripley et al, 2011;Milne et al, 2014;Frost et al, 2017a;Loiseau et al, 2018). Nevertheless there still lacks definite and quantitative characterization of the spatiotemporal evolution of jetting structure largely owning to the difficulties and uncertainties of reconstructing threedimensional jetting structures from two-dimensional images.…”

“…Particle jetting during the explosive or shock dispersal of particles has been widely observed in nature and many military applications, such as volcanic eruption (Kieffer, 1981), explosion of landmines (Rigby et al, 2018), thermobaric explosion (Ritzel et al, 2009;Bai et al, 2018), high-speed intruder striking granular media, and particle jets impacting targets (Shi et al, 2017;Huang et al, 2010), etc. A typical configuration involves particle rings or shells dispersed by the explosion of central charges (Milne et al, 2010;Ripley et al, 2011;David et al, 2012;Xue et al, 2013;Milne et al, 2014;Ripley and Zhang, 2014;Frost et al, 2017aFrost et al, , 2017bBai et al, 2018;Loiseau et al, 2018;Pontalier et al, 2018;Marr et al, 2018). The resultant expanding cloud of disseminated materials comprises of large particle agglomerates which rapidly protrude to finger-or spike-like particle jets as shown in Fig.…”

“…Mainly due to the limits aforementioned, there are no widely accepted mechanisms governing the jetting formation and dictating the resulted jetting structure (Milne et al, 2010;Grégoire et al, 2011;Ripley et al, 2011;Xu et al, 2013Xu et al, , 2014Ripley and Zhang, 2014;Loiseau et al, 2018;Osnes et al, 2018). The Rayleigh-Taylor instability (and other hydrodynamic instabilities such as Richtmyer-Meshkov or Kelvin-Helmholz) has been excluded as a possible candidate owing to the inconsistence between the theoretically predicted characteristic timescale and that derived experimentally (Milne et al, 2010;Milne et al, 2014;Ripley and Zhang, 2014).…”

Heterogeneous/particle-laden blast waves

“…Experimentally, Loiseau et al [18] focus on the terminal velocity attained by the accelerated material, extracted from high-speed images, and compare the results with predictions from the conventional Gurney model as well as a modified version. They quantify the differences in the predictions for solid particles and liquids, as compared with the experimental results.…”

“…Particle jets are formed as the fragments move radially outwards, and shed particulate in their wakes (d). Figure adapted from Loiseau et al [18] Recent experiments by Wagner et al [16] within a multiphase shock tube have provided a well-characterized dataset for the validation of the physical processes that occur during the shock interaction with a dense array of particles in air. Ling et al [17] have demonstrated that the processes associated with the shock interaction with a dense particle curtain differ significantly from those in a dilute gas-particle mixture.…”