Dynamics of a Rotating Sphere on Free Surface of Vibrated Granular Materials

• 来源期刊: 中国物理快报（英文版）
• 年，卷（期）: 2018,（8）
• 页码范围: 44-48
• 页数: 5页
• 语种: 英文
• DOI: 10.1088/0256-307X/35/8/084501

摘要

We investigate the rotational dynamics of a low-density sphere on the free surface of a vertically vibrated granular material (VGM).The dynamical behavior of the sphere is influenced by the external energy input from an electromagnetic shaker which is proportional to ε,where ε is equal to the ratio between the square of the dimensionless acceleration F and the square of the vibration frequency f of the container.Empirical results reveal that as the VGM transits from local-to-global convection,an increase in ε generally corresponds to an increase in the magnitudes of the rotational ωRS and translational vCM velocities of the sphere,an increase in the observed tilting angle θbed of the VGM bed,and a decrease in the time twan it takes the sphere to roll down the tilted VGM bed and hit the container wall.During unstable convection,an increase in ε results in a sharp decrease in the sphere's peak and mean ωRS,and a slight increase in twall.For the range of ε values covered in this study,the sphere may execute persistent rotation,wobbling or jamming,depending on the vibration parameters and the resulting convective flow in the system.