摘要

本模擬使用了直徑相同密度不同的兩種顆粒，其中有一顆密度與其他顆粒不同，稱之為追蹤顆粒，其他顆粒則稱為環境顆粒。改變追蹤顆粒與環境顆粒的密度比，模擬了密度比為0.1、0.25、0.5、0.75、1.25、1.5。將追蹤顆粒放置在底層的中間，並模擬了在不同層數堆積下所造成的結果。

5層時，其密度越小所需要的臨界無因次加速度Γc值越小。10層時，趨勢與5層相似，但不同的是，其上升所需的臨界無因次加速度Γc值較5層要大，且追蹤顆粒基本上是由兩邊上升至頂端，而5層則大多數由中間上升至頂端。15層則與5、10層不太相同，相同密度比下，振幅越小所需要的Γc值也越小。密度比大於1時，15層不論給予多大的振幅及Γc值，始終無法使追蹤顆粒上升。

Abstract

. In the simulations of the present study, we use two kinds of spherical particles made of identical material with different densities. The particle with differenty,named trace particle, is set in the bottom-middle of the container surrounded by the surrounding particles. We change the density ratio of tracing particle and surrounding particle, and simulate the situation when the density ratio is 0.1, 0.25, 0.5, 0.75, 1.25, and 1.5.

When the layers are 5, the critical dimensionless acceleration (Γc) is smaller as the density ratio become smaller. The trend of 10 layers is just like the 5 layers’, but the Γc is bigger than the 5 layers’. The trace particle goes to the top layer from the side of the system while the layers are 10, but it goes to the top layer from the middle of the system. The 15 layers’ critical amplitude decreases as the density ratio increases, and the Γc increases as the density ratio increases. The different between 15 layers and 5, 10 layers is that the dimensionless acceleration decreases as the amplitude decreases with the same density ratio. And the tracing particle can’t go to the top layer no matter how much the Γ we give while the density is bigger than 1.

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