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題名 | 植生地表上均勻降雨之水理分析=Hydraulic Analysis of Water Flow Passing over Vegetated Areas under a Uniform Rainfall |
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作者 | 胡秀怡; 謝平城; Hu, Siou-yi; Hsieh, Ping-cheng; |
期刊 | 中華水土保持學報 |
出版日期 | 20120900 |
卷期 | 43:3 2012.09[民101.09] |
頁次 | 頁255-263 |
分類號 | 434.273 |
語文 | chi |
關鍵詞 | 孔彈性介質理論; 漫地流; 均勻降雨; 植生; Poro-elasticity theory; Overland flow; Uniform rainfall; Vegetation; |
中文摘要 | 植生的存在不僅影響水流流況,還會增加水流之阻抗,爰此,為瞭解植生對於均勻降雨之地表水流流速和水深之影響,本文從水力學的觀點出發,將流場分成均質水層、水草混合層和無限厚透水土層(以下簡稱水層、草層、土層),以Navier-Stokes方程式來描述水層之流況,將草、土兩層中之流體視為孔隙介質流的運動,且引入宋(1993)所建立多孔介質層流模式加以描述之,最後搭配Runge-Kutta法而求得其半解析解。文中分成水深不及草高、水深漫過草高與混合型三部分討論,並與裸露地上均勻降雨之情況進行比較,結果顯示植生存在之地表,其水流流速明顯地下降。此外探討坡度、降雨強度和比滲透係數等因子對流況之影響,及在各種狀況下植生阻力之變化,以期研究成果在環境和生態工程之設計及地表水的管理上能有所助益。 |
英文摘要 | The existence of vegetation not only significantly affects flow, but also increases resistance to flow. To understand the effect of vegetation on flow velocity and water depth, a semi-analytical approach was proposed to study flow passing over vegetated areas under a uniform rainfall event. In this study, the flow region was divided into three layers-- homogenous water layer, water-plant mixing layer, and infinitely thick permeable soil layer (briefly denoted by water layer, vegetation layer, and soil layer).The flow of the water layer was governed by the Navier-Stokes equations. The vegetation and soil were both regarded as porous media and Song's (1993) laminar model modified from Biot's theory of poroelasticity was applied. The semi-closed solutions were then obtained via the Runge-Kutta method. Three cases--submerged vegetation, emergent vegetation and submerged-emergent vegetation were discussed. The results were compared with those of the unplanted ground case, showing the flow velocity obviously decreases with vegetation. Additionally, the effect of slope, rainfall intensity, and permeability on the flow and the resistance resulting from vegetation were also discussed. The results are believed to be helpful in environmental and ecological engineering design and surface water management. |
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