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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/69232

    Title: 水中顆粒體崩塌分析與電腦模擬比對
    Authors: 林傳遠;LIN-CHUAN-YUAN
    Contributors: 機械工程學系
    Keywords: 顆粒流;granular flows
    Date: 2015-10-12
    Issue Date: 2015-11-04 17:51:54 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 土石流、水災和山崩等天災在地球已經造成許多人死亡,所以能夠深入探討顆粒內部的流動行為的話有助於了解土石流的崩塌機制。本論文主要是在狹窄流道內進行乾顆粒崩塌與水中顆粒崩塌實驗,並且針對水中顆粒崩塌實驗的結果與DEM模擬結果進行比對。此外我們將會比對不同顆粒堆高寬比和不同粒徑大小的顆粒在崩塌過程中的流動行為。為了要能夠分析顆粒流的流動行為,我們藉由Voronoi影像處理技術來得到顆粒流的速度。
    ;The disasters like debris flows, flooding and avalanches have caused many deaths and injuries on the earth, and it is important to understand the inner behavior of debris flows. In this thesis, we will investigate the collapse of rectangular granular piles in the narrow channel for both dry and wet conditions, and validate the DEM simulation with the corresponding experimental results in wet condition. The effects of different aspect ratios and particle diameters on the behavior of granular flows during collapse are also analyzed. We use the Voronoi imaging method to measure the velocity of granular flow.
    Some characteristics such as distribution of velocity, velocity profile, thickness of flowing layer and flow rate at the outlet are analyzed in this thesis. Results show that greater velocity on the flowing layer occurs in the high aspect ratio. Likewise, larger particle tend to have greater velocity on the flowing layer during collapse. The flow rate and flowing layer at the outlet reach a maximum initially and decline with time. As the aspect ratio increases, the greater flow rate occurs at the initial period, and declines sharply with time. In the comparison of different particle diameters, the flow rate declines more slowly for large particles than for small particles. By comparison with experimental data, the simulation results show greater flow rate at the outlet and the great velocity in the free surface at initial collapse. However, both results between experiment and simulation show good agreement at later period. The pressure dip is obvious in the formation of the granular pile at initial collapse.
    Appears in Collections:[機械工程研究所] 博碩士論文

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