以實驗探討顆粒流之崩落流動狀態

Experimental study on the spreading flows of granular material

黃智煜(Zhih-Yu Huang)

指導教授 ： 戴義欽

國立暨南國際大學/科技學院/土木工程學系/碩士(2009年)

https://doi.org/10.6837/NCNU.2009.00135

摘要

自然界中山崩的土石運動現象可藉由顆粒材質的不同而演變出各種崩塌堆積型態，然而這些土石崩落現象一直是我們感興趣的研究範圍。
現階段本研究將以實驗方式建立一二維立面模型來探討其崩落運動現象，研究中將利用高速攝影機將實驗過程拍攝並且紀錄，並且透過影像處理描繪出流動層及堆積層，以討論流動層與堆積層隨時間的動態演變過程。
研究中將設計一系列之實驗規劃項目，如以標準砂20-30、30-50、圓球形玻璃珠1 mm及2 mm顆粒材質搭配傾角0度、2度、5度及10度實驗項目，過程中並有改變其高寬比為1：1.5及增加底床摩擦係數之實驗項目，藉由以上實驗規劃提出顆粒材質間之崩落現象如最終堆積型態、顆粒材質流動時間與堆積距離之比較及最終表面崩塌角等等。實驗最後應用粒子影像測速技術來量測顆粒體流動層之速度向量，希望由以上分析項目更進一步探討出其崩落之動力機制。

關鍵字

顆粒流 ； 堆積層 ； 流動層 ； 粒子影像測速技術

並列摘要

In nature, deposit profiles of avalanches vary with the debris constituents, e.g. grables, ruptured rocks, sand, etc. study of the influence of material types on the deposits is the main theme of the present dissertation.
We experimentally measured two-dimensional collapse flows. Flow images are taken by a high speed camera and are analyzed by a PIV (Particle Image Velocimetry) software (proVision) for flow velocity field. By the image method, temporal evolution of the flowing layer and deposition heap are presented and discussed.
Glass beads of diameter 1 mm and 2 mm, and Ottawa sand 20-30 and 30-50 are used in the series of experiments. Planary chute is used and four inclination angles, 0∘, 2∘, 5∘and 10∘are tested. Geometric influence of the initial height-widths ratios (1：1 and 1：1.5) are investigated. Finally, different basal conditions, smooth and rough, are also performed.

並列關鍵字

granular flow ； flowing layer ； deposition-heap ； PIV

參考文獻

參考文獻

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[3]S. Douady, B. Andreotti, A. Daerr, and P. Cladé.“From a grain to avalanches: on the physics of granular surface flows.”Comptes Rendus Physique, 3, 177-186, (2002).

[4]L. Erica, Thompson and H. E. Huppert.“Granular column collapses:further experimental results.”Journal of Fluid Mechanics, 575, 177-186, (2007).