The Force on Intruder in Vibration Granular Bed

In this paper, a column is put in a vibrated bed as an intruder to study the force of bed by changing intruder’s mass and vibration strength. Our result indicates that the granular material is completely different with conventional fluid, which the force on intruder does not satisfy with Archimedes Law. The force is strongly influenced by its position in bed, as well as its size, shape and vibration strength. The deeper the intruder immerges, the bigger the force is. Because of the different forces, the interesting phenomena granular separation, that the intruder can not only rise to the top, but also sink to the bottom, and even keep in the middle of the bed, are present.