Simulation-driven design of experiments examining the large-scale, explosive dispersal of particles

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A series of six, large-scale tests were performed at the Eglin Air Force Base blastpad facility to serve as a validation benchmark for the explosive dispersal of particles. The series contained two baseline tests, one tungsten liner test, and three steel liner tests. Careful emphasis was placed on design of the experiments to allow ease of simulation, uncertainty quantification of experimental inputs, and extraction of prediction metrics. Design decisions, such as using a casing that is negligible to the flow, serve to greatly reduce the computational effort to perform validation. Attention is also paid to quantifying uncertainty in experimental inputs such as explosive density, particle size distribution, particle density, volume fraction, and ambient conditions. For each test, data were collected from four high-speed cameras, 54 inground pressure transducers, and eight unconfined momentum traps. From these diagnostics, prediction metrics are extracted measuring the shock time of arrival, peak pressure, impulse per unit area, and the contact/particle front position. The high-speed video shows significant differences between the steel and tungsten liners. The tungsten particles were incandescent as they dispersed and concentrated in a bright, dense band followed by alternating bright and dark striations. There was little to no incandescence in the dispersed steel particles. The steel liner tests exhibited instabilities with fine fingers racing ahead of the front. The instabilities, however, were so numerous that they are not easily distinguishable from each other, preventing their characterization.