Energy Equipartition In Granular Brownian Motion

• Main Authors: Chun Wang, 王鈞
• Other Authors: To,Kiwing
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/90942528565500341801

碩士 === 國立臺灣師範大學 === 物理學系 === 103 === We study the Brownian motion of a macroscopic (centimeter size) granular object surrounded by a granular gas composed of millimeter size spheres acting as the molecules. While the system is vibrated vertically by an electromagnetic shaker, we use a fast camera to capture the temporal variations of the horizontal position and the orientation from above. From the captured image sequences, we manage to measure the translational and the rotational velocities in the horizontal plan. Suprisingly, we find that the average kinetic energies carried by the translational degrees of freedom and the rotational degree of freedom of the disk are the same within experimental uncertainty. Hence energy equipartition is found to valid even for nonequilibrium granular systems. We find granular object obey Equipartition law. Then, we do the two dimentional molecular dynamic simulation and we find granular object won’t obey Equipartition law unless the granular object surface is extremely rough.