本論文研究在垂直式振動床系統中改變容器底盤粗糙因子對巴西豆現象的影響。在實驗中首先藉由高速攝影機觀察紀錄顆粒體的動態行為，之後再藉影像技術及粒子追蹤方法計算出粗糙因子在不同振動條件下，大顆粒的垂直上升軌跡以及粗糙因子對顆粒體的傳輸性質的影響，最後討論粗糙因子在類二維系統及三維系統中對於巴西豆現象的影響是否一致。實驗結果顯示大顆粒的上升時間會隨粗糙因子的增加而增加，且在較小的無因次振動加速度及較大的振動頻率下，粗糙因子的不同對大顆粒上升時間的影響越明顯。大顆粒的滲透長度會隨著粗糙因子的增加而減少，粗糙因子越大，在每次振動下大顆粒與背景粒子間的消散的摩擦力也越大。此外，顆粒體的傳輸性質會隨著粗糙因子的增加而減弱，在粗糙因子較小的時候，因顆粒床所獲得的能量較多，故顆粒床的傳輸性質會比較強。在傳輸性質較強的情況下顆粒床流體化的現象會越明顯，造成分離現象較為顯著，大顆粒所需的上升時間也就較短；粗糙因子較大時，顆粒床體所能獲得的能量也較少，傳輸性質也會隨之減弱，顆粒床流體化程度降低也會造成大顆粒上升的時間增長。最後，實驗結果顯示不同粗糙因子對於巴西豆現象的影響在類二維系統與三維系統中相同。This study investigates experimentally the effect of the bumpy surfaces on Brazil-nut phenomenon in a vertical vibrated granular bed. The motions of the particle are recorded by a high speed camera and the dynamics of particles are measured by particle tracking method, and discuss the effect of roughness factor in quasi-2D and 3D system. The results show that the rising time increases with the increasing roughness factor, and the difference of the rising time with different roughness factor is more significant with the smaller dimensionless vibration acceleration and higher vibration frequency. It also shows that the penetration length of the intruder decreases with the increasing roughness factor, and the friction drag force between the intruder and the background particle increases with the increasing roughness factor. Additionally, the transport properties of particles decrease with the increasing roughness factor. The tank which has smaller roughness factor can obtain greater energy from vibrated bed, and causes the greater transport properties of granular bed. Hence the smaller roughness factor case has smaller rising time and stronger Brazil-nut phenomenon. The tank with the bigger roughness factor could receive smaller energy from vibrated bed, resulting in the weaker transport properties. Hence the bigger roughness factor case has the longer rising time and weaker Brazil-nut phenomenon. Finally, the result shows that the influence of roughness factor on Brazil-nut effect in quasi-2D and 3D system is similar.
