Dissipation behaviors of suspended granular balls in a vibrated closed container

Abstract

To reveal the dissipation mechanism of suspended granular phases reported in the previous research, Leidenfrost effect, Buoyancy convection and Bidirectional Leidenfrost effect of granular balls in a quasi-two-dimensional vibrated container are studied by means of Discrete Element Method (DEM). Dynamical behaviors and dissipation characteristics of the three suspended granular phases obtained by three sets of different excitation parameters are explored respectively. Simulation results show that phase separation phenomenon occurs in all suspended granular phases, and the main difference between three suspended granular phases is the internal structure of levitated dense granular cluster. All suspended granular phases show two different loss regions, i.e., the linear loss region that locates in the dilute gaseous layers and the nonlinear loss region that locates in the levitated dense granular cluster. Moreover, the high damping effect of the three suspended granular phases is explained, i.e., the jamming transition of granular balls may be reversible and occur frequently in the levitated dense granular clusters. Finally, based on the revealed dissipation behaviors of suspended granular phases, an improved effective damping parameter is put forward to evaluate the damping effect of granular balls, which can characterize the dissipation properties of vibrated granular balls more comprehensively.