Lim E W C
Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore.
Eur Phys J E Soft Matter. 2010 Aug;32(4):365-75. doi: 10.1140/epje/i2010-10637-8. Epub 2010 Sep 5.
The effects of subjecting a bed of granular materials to horizontal vibrations by a bumpy oscillating surface have been investigated computationally in this study. The behaviour of the granular bed is determined by the vibration conditions applied which include the vibrating frequency and amplitude as well as the bumpiness of the oscillating surface. Under sufficiently vigorous vibration conditions, the granular Leidenfrost effect whereby the entire granular bed is levitated above the vibrating base by a layer of highly energetic particles may be observed. Granular temperature profiles of systems that exhibit the granular Leidenfrost effect indicate an unequal distribution of energy between particles near the vibrating base and those in the bulk. A bumpy oscillating surface was also observed to be more effective at introducing perturbations and transferring energy into a granular bed. The granular Leidenfrost effect can be induced by the application of larger grain sizes of particles constituting the bumpy vibrating base under vibration conditions that are normally insufficient for the onset of the effect. Lastly, a phase diagram which can be utilized for predicting the behaviours of granular beds that are subjected to oscillations by various types of bumpy surfaces has been constructed based on the simulation results obtained.
在本研究中，通过颠簸的振荡表面对颗粒材料床施加水平振动的影响已通过计算进行了研究。颗粒床的行为由所施加的振动条件决定，这些条件包括振动频率、振幅以及振荡表面的颠簸程度。在足够剧烈的振动条件下，可以观察到颗粒莱顿弗罗斯特效应，即整个颗粒床被一层高能粒子悬浮在振动基座上方。表现出颗粒莱顿弗罗斯特效应的系统的颗粒温度分布表明，靠近振动基座的颗粒与主体中的颗粒之间能量分布不均。还观察到颠簸的振荡表面在引入扰动和将能量传递到颗粒床方面更有效。在通常不足以引发该效应的振动条件下，通过应用构成颠簸振动基座的较大颗粒尺寸，可以诱导颗粒莱顿弗罗斯特效应。最后，基于获得的模拟结果构建了一个相图，可用于预测受各种类型颠簸表面振荡的颗粒床的行为。
