均勻降雨下有限厚土層之植生地表水理分析

Hydraulic Analysis of Water Flow Passing Over Vegetated Areas with Finite Thick Soil Layers under Uniform Rainfall

10.29417/JCSWC.201303_44(1).0002

胡秀怡(Siou-Yi Hu)；謝平城(Ping-Cheng Hsieh)

孔彈性介質理論 ； 漫地流 ； 均勻降雨 ； 植生 ； Poro-elasticity theory ； overland flow ； uniform rainfall ； vegetation

中華水土保持學報

44卷1期（2013 / 03 / 01）

11 - 22

繁體中文

本研究將流場分成均質水層、水—草混合層和有限厚透水土層（以下簡稱水層、草層、土層）。考量坡地表面透水，且地表下的水流為孔隙介質流，因此地表水流速度不為零。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。文中分成非浸沒型（水深不及草高）、浸沒型　（水深漫過草高）與混合型三種類型討論，並探討坡度、降雨強度、土層厚度和植株直徑等因子對流況之影響，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。

To understand the effect of rainfall on water flow down a slope, the flow region was divided into three layers-the homogenous water layer, mixed water-plant layer and finite thick soil layer. The flow of the water layer was governed by the Navier-Stokes equations. The vegetation and soil layers were both regarded as porous media and the laminar model modified from Biot's theory of poroelasticity was applied. The semi-analytical solutions were then obtained via the Runge-Kutta method. Three patterns-submerged vegetation, emergent vegetation and submerged-emergent vegetation-were discussed. Additionally, the effect of slope, rainfall intensity, thickness of soil layer and plant diameter on the flow were also discussed. The results are believed to be helpful in environmental and ecological engineering design and surface water management.