顆粒追隨現象

Granular Follower

朱立民(Li-Min Ju)

指導教授 ： 葉超雄

共同指導教授 ： 陳國慶

國立臺灣大學/工學院/應用力學研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.00330

摘要

『顆粒鐘現象』（granular clock）於2005年進行模擬時發現，並於2006年以實驗方式證明。然而，研究至今，系統僅為二等分，侷限於二格顆粒鐘。

本文以實驗方式，探討不等顆粒數、不等粒徑比，於不等振幅配置下，產生之顆粒鐘現象。由實驗結果得知，產生良好顆粒鐘現象的條件相當嚴苛，且影響此現象的變因甚多。

將容器延伸為三等分，進行三格容器實驗時，吾人發現了『顆粒追隨現象』（granular follower），以及顆粒離開容器內外側聚集區的時間差異現象。『顆粒鐘現象』可視為『顆粒追隨現象』在二等分系統中的特例。我們提出簡易三格顆粒追隨現象模型，並進行了四等分容器的四格容器實驗，成功印證這兩項新發現的物理現象。

最後，本研究藉由改變大小顆粒直徑比、改變小顆粒粒數，進行兩個系列的實驗。探討改變此兩種變因，對於顆粒聚集時間的影響，以及飛越格數不等的機率問題。

關鍵字

顆粒追隨 ； 顆粒鐘 ； 顆粒聚集 ； 反巴西堅果效應 ； 顆粒材料

並列摘要

The phenomenon called “granular clock” was discovered by numerical simulations (2005) and proven by experiences (2006). So far, however, the design of system was only divided into two equal compartments.

In this thesis, some “granular clock” experiments to discuss the influences factors, such as the number of small particles, the diameter ratio of particles, and the amplitude of vibration have been established. The results show that there are critical confinements to make an obvious granular clock phenomenon.

The experiments started with the container divided into three equal compartments, and two new physical phenomena are discovered. One of them was named “granular follower”, and the other one represented the different time of particles leaving from two sides or central compartment of the container. We also proposed a model about “granular follower” for the system with three compartments. Moreover, the experiments with the container divided into four equal compartments were made to prove the aforementioned phenomena. Consequently, it is suggested that “granular clock” is a special case of “granular follower” only for the systems divided into two equal compartments.

In addition, two series of experiments were made to investigate the effects of influence factors, such as the relative ratio of particle diameters and the number of small particles, so as to discuss the influence of clustering time and the distribution probability of particles in different compartments in the system.

並列關鍵字

granular follower ； granular clock ； granular clustering ； reverse Brazil nut effect ； granular material

參考文獻

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