Abstract
This paper describes behavior of fine particles in a laterally vibrated box under microgravity and shows the effects of vibrating conditions and particle concentration on the behavior. A drop capsule yielded microgravity for 10 seconds. Particles of 51μm in mass median diameter flew upward along with each side wall vibrating at 75-150Hz and were dispersed into the central part of the box. The propagation rate of momentum in the particles from the vibrating walls was determined by the frequency and the particle concentration in the dispersed phase. For a small loading mass, static clusters were formed due to restricted propagation of momentum. However, the propagation was enhanced to generate dynamic clusters which were transitional assemblies of the moving particles at a high particle concentration or at a high frequency. It was found that there exists a saturating concentration of dispersed particles in a fully developed vibrating state. High particle concentration leads to a supersaturation and therefore bed reformation from the dispersed particles.
