堆積顆粒受水流作用下形成土石流之渠槽實驗

Experiments of debris flow induced by accumulation of particles by the action of water at the flume

涂毅宏(Yi-hong Tu)

指導教授 ： 周憲德

國立中央大學/工學院/土木工程學系/碩士(2011年)

摘要

本研究進行礫石型土石流之渠槽實驗，以高速攝影機及影像分析堆積顆粒受到上游供水的壓力與滲流作用下產生破壞行為及運動特性。本研究採用Voronoï Patterns 方法分析顆粒流中顆粒的速度向量及其流動特性。在顆粒流體化的過程中，前端龍頭與水非均勻混合，且顆粒在前端有集中隆起的情況。顆粒流中滲流線前後段的顆粒速度及顆粒濃度也有所差異，這些現象與現地土石流之流況相近。
　　本研究改變上游的供水量以及渠槽角度進行不同的實驗，並分析顆粒流上視及側視的速度剖面，與前人的數值及實驗結果進行比較。結果顯示實驗中的顆粒運動較符合Bagnold速度剖面的條件，並與礫石型土石流有相同的流動特性。

關鍵字

顆粒流 ； 土石流 ； 速度剖面

並列摘要

This research carries out granular flow experiments, by using high-speed camera to observe the role of particle movements caused by runoff. The flow behavior of accumulation of particles by the upstream water supply pressure and seepage, are examined and the image analysis technology to analyze the characteristics of granular flow. In this study, we use Voronoï Patterns method to analyze the velocity vector and flow characteristics of granular flow. In the process of fluidization, the combining of the particle and water is non-uniform in the snout. The particles accumulated in the snout are not saturated and the wave front becomes a bulb.

並列關鍵字

velocity profile ； debris flow ； granular flow

參考文獻

4. Berzi., D., and J. T. Jenkins, (2009), “Steady Inclined Flows of Granular-Fluid Mixtures”, J. Fluid Mech. (2009), Vol. 641, pp. 359-387.

5. Capart, H., D. L. Young and Y. Zech (2002),“Voronoï Imaging Methods for the Measurement of Granular Flows”, Experiments in Fluids, Vol. 32 (2002), pp.121-135.

7. Hsu, L., W. E. Dietrich and L. S. Sklar (2008), Experimental Study of Bedrock Erosion by Granular Flows”, Journal of Geophysical Research, Vol. 113, F02001, doi:10.1029/2007JF000778, 2008.

8. Jop, P., Y. Forterre and O. Pouliquen (2005), “Crucial Role of Sidewalls in Granular Surface Flows: Consequences For the Rheology”, J. Fluid Mech. (2005), Vol. 541, pp. 167-192.

9. Pouliquen, O. (1999), “Scaling Laws in Granular Flows Down Rough Inclined Planes”, Physics of Fluids, Vol. 11, No. 3., pp. 542-548.