An experimental study of the mechanical structure of a cloud of particles dispersed from a dust layer by a shock passage.

Abstract

Shock tube experiments were performed to investigate the initial stage of dust dispersion by a shock which propagates over a dust layer deposited on a solid floor. Amberlite was used as a model dust because it promised good reproducibility of experiments. The profiles of the densities and the velocity components of the dispersed dust particles above the dust layer were determined through the trajectories on the visualized photographs, which were taken using double-flashed light sources. It was found that the density near the dust layer is much larger than usually expected, that its profiles for different shock Mach numbers are reduced to a single curve when non-dimensionalized distance is taken, m and that the heights of the dust cloud and the dimensionless velocity profiles for different Mach numbers can be reduced to each single curve where reasonable abscissas are chosen, respectively. The comparison of velocity components for various floor conditions revealed that surface roughness is one of the important factors for the mechanism of dust dispersion by a shock wave.