本研究進行不同角度、落距之泥滴撞擊試驗，並結合數位相機及高速攝影機擷取影像，以探討土石流泥漬的幾何特性與土石流峰前運動條件的關係。實驗所得影像利用圖像剪輯、數位讀取及MATLAB內建計算程式，分析泥滴撞擊濺痕的歷程及形狀、短長徑比等關係。由實驗結果可歸納出濺痕面積、裂痕數及最大裂痕長度皆隨撞擊速度的增加而變大；撞擊角度的增加會使濺痕數增加，然而濺痕面積卻隨之減少。在不同落距下，濺痕的短長徑比皆相近於撞擊角度的正弦値。裂痕分部近似於馬克斯威爾分部，而液滴之上蓋輪廓則近似於beta方程式。本研究之成果有助於分析土石流峰前速度特性，並由泥漬特性判定撞擊時之土石流現場運動條件，以提升土石流防治設施的效益。

The fingered splatter left behind after a liquid drop impacts a solid surface with different impact velocity and impact angle are experimentally examined in this study. The impact velocity of the droplet is varied by different falling distances, and the impact angles of the droplet impacting platform varies from 15° to 90°. The MATLAB counting program, image software, and a high speed camera are used to analyze the geometry property of the splatter. With increasing impact velocities, the area and the fingers of splatter also first increase, then approach constant value when the droplet reach ultimate impact velocity. Larger the impact angle, exhibits more splatter fingers but smaller the splatter area. The ratio of the short axis to the long axis is approximate to sin value of the impact angle. Length distribution of fingers approximate to Maxwell distribution while the droplet contour side view is close to the Beta function.

1. 翁景惠，程曉桂(1997)，「血跡噴濺痕」，書祐文化事業有限公司，pp.23-38。
2. 陳昱豪(2003), 「泥漬痕跡幾何特性與土石流峰前運動條件之關係」， 國科會暑期大專生參與研究計劃研究成果報告。
3. Lighthill, J. (1978), Waves in Fluids , Cambridge University Press, Cambridge, pp.226.
4. Brochard, F., de Gennes, P. G.(1984), “Spreading laws for liquid polymer droplets: interpretation of the <foot>”, Journal of Physique Lett., vol.45, Juin 1984, PP.597-602
5. Mundo Chr., Sommerfeld, M., and Tropea C.(1995) “Droplet-wall collisions: experimental studies of the deformation and breakup process”, Int. J. Multiphase Flow, vol. 21, No. 2, PP.151-173
6. Marmanis, H.and Thoroddsen S.T. (1996), “Scaling of the fingering pattern of an impacting drop”, Physics of Fluids, vol.8, no. 6, June 1996, pp.1344-1346.
7. Pasandideh-Fard M.,Qiao Y. M.,Chandra S., and Mostaghimi J.,”Capillary effects during droplet impact on a solid surface”, Physics of Fluids, vol.8, no. 3, March 1996, pp.650-659.
8. Thoroddsen S. T. and Sakakibara J. (1998),” Evolution of the fingering pattern of an impacting drop”, Physics of Fluids, vol.10, no. 6, June 1998, pp.1359-1374.
9. Munson, B.R., Young D.F and Okiishi T.H. (1998), Fundmentals of Fluid Mechanics, John Wiely and Sons Inc., New York.
10. Bhola, R., Chandra, S. (1999), “Parameter controlling solidification of molten wax droplets falling on a solid surface”, journal of materials science, vol. 34, pp.4883-4894
11. Kim, H. Y., Feng, Z. C., Chun, J. H. (2000),”Instability of a liquid jet emerging from a droplet upon collision with a solid surface”, Physics of fluids, vol. 12, 531-541
12. ElSherbini, A. I., Jacobi, A.M. (2004), “Liquid drops on vertical and inclined surfaces I. An experimental study of drop geometry”, Journal of Colloid and Interface Science, vol.273, May 2004, pp.556-565
13. Mehdizadeh, N. Z, Chandra, S., Monstaghimi, J. (2004),”Formation of fingers around the edges of a drop hitting a metal plate with high velocity”, Journal of fluid mechanics, vol. 510, pp.353-373
14. Šikalo, Š., Tropea, C., Gani´c E.N. (2005), “Impact of droplets onto inclined surfaces”, Journal of Colloid and Interface Science, Jan 2005, pp.661-669
15. Yoon, S. S., Jepsen, R. A., Nissen, M. R., O’Hern, T. J. (2007), “Experimental investigation on splashing and nonlinear fingerlike instability of large water drops”, Journal of fluid and structures, vol. 23, pp.101-115