摘要
在垂直振动的激励下,铜和玻璃珠组成的二元颗粒混合样品存在依次出现分界清晰的三明治,巴西果,反巴西果三种分聚结构的周期循环变化现象,其中出现三明治结构的时段最长(大于90%).循环周期随振动台频率的增加而增大,随加速度的增加而减小.对三种分聚结构的样品能量耗散功率的测量显示,在相同的振动条件下反巴西果结构的能耗功率最大,巴西果结构的最小.利用Hong的凝聚和渗透两机理相互竞争的观点,并结合能耗功率的测量结果,可定性解释这个周期性分聚现象.
For a vertically vibrating column filled with binary mixtures consisting of big copper beads and small glass beads, the phenomenon of periodic segregation （PS） is observed experimentally, in which distinct segregation patterns of Brazil nut effect （BNE）, reversed Brazil nut （RBN） and sandwich （SW） are emerged successively under a certain vibration condition. The periodic time increases with increasing vibration frequency or decreasing acceleration, and the SW pattern holds 90% duration of a cycle. Since the three segregation patterns emerging sequentially in a cycle are all well defined, the energy dissipation power for each segregation pattern is measured under the same vibration condition. It is found that the dissipation power is the largest in RBN pattern and the smallest in BNE pattern during a cycle. Moreover, in the periodic segregation region the same patterns （BNE, RBN or SW） emerging at different vibration accelerations have almost the same dissipation power within the experimental error. Based on the viewpoint of competition between condensation and percolation from Hong, the periodic segregation phenomenon can be explained qualitatively by combining with our measurements of energy dissipation power.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第13期219-227,共9页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11274390)资助的课题~~
关键词
颗粒物质
能量耗散
分聚
granular matter
energy dissipation
segregation
