Modification and discussion of the Green-Ampt model for an evolving wetting profile |
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| Authors: | Qiyong Zhang Yuzhen Kong |
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| Institution: | 1. Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, Lanzhou University , Lanzhou, China;2. College of Civil Engineering and Mechanics, Lanzhou University , Lanzhou, China;3. School of Mathematics and Statistics, Lanzhou University , Lanzhou, China |
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| Abstract: | ABSTRACT The Green-Ampt (GA) model has been widely used to evaluate soil water infiltration. While a simple piston profile is commonly used, the wetting profile of a soil changes during infiltration and a quarter-ellipse has been found to better describe its evolution. This study aims to improve the GA model and discuss the model parameters when the quarter-ellipse profile is utilized. The soil column is divided into three zones: saturated, transient and dry. The variable γ is introduced to express the ratio of the saturated zone depth to the wetting front depth. A modified GA model is derived via mathematical methods, but an exact solution is difficult to obtain. Therefore, a simplified (SGA) model is developed via a segmented method. Compared with the measured results, the SGA model is more accurate than the traditional model. Finally, the model parameters are discussed and a value of γ = 0.5 is recommended. |
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| Keywords: | Green-Ampt model wetting front depth quarter-ellipse profile wetting profile |
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