ABSTRACT
Vibrofluidization of vertically vibrated granular layers characterized by intensive kinetic energy dissipation had been shown to be impossible. Yet we found that when subject to low-frequency, high amplitude vertical oscillations, both 2-D and 3-D layers show vigorous fluidization even for particles with very low restitution coefficients. These regimes are examined by high-speed video-recording and the concomitant data collected are processed to elucidate the granular average velocity and temperature, resulting from the compression waves’ propagation. In parallel, vibrofluidization is numerically modeled by one-dimensional arrangements of inelastically colliding spheres moving in a vertically oscillating vessel to reveal a physical mechanism responsible for vibrofluidization. We found that in these columns vibrofluidization results from the transitions from the fluidized regime to the packed regime (formation of clusters) and back, both prevailing interchangeably for highly dissipative granules. These transitions are governed by the particle detachment mechanism, which underlies disintegration of granular clusters. This mechanism explains vibrofluidization of 2D and 3D vibrated granular layers observed in the experiments.
