粉体層上を伝播する衝撃波によって形成される粉体雲の可視化

抄録

In order obtain better understanding of the mechanisms of particle entrainment due to a propagating shock wave, we visualized particle-cloud formation process in a shock tube facility by the shadowgraph technique coupled with a high-speed video camera. In the present experiments, limestone particles (nominal average diameter of 1.9 μm) with a layer thickness of 12.7 mm were subjected to incident shock waves with a propagating Mach number of 1.3. Temporal evolutions of the height of particle cloud were then obtained from the shadowgraph images. The present visualization experiments revealed that (1) the boundaries of particle clouds were smoothly distributed just behind incident shock waves, but ripples appeared near the boundaries about 0.2 ms after shock passage, and (2) the ripples grew into small clusters of particles.