IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 35th IAHR Congress - Chengdu (2013) : THEME 7 - WATER RESOURCES AND HYDROINFORMATICS : Assessment of a 3D Variably Saturated Subsurface Model
Assessment of a 3D Variably Saturated Subsurface Model
Author : Daniel Caviedes-VoulliŠme, Javier Murillo and Pilar Garcˇa-Navarro
Some environmental, irrigation and engineering applications have a special interest in the accurate simulation of 3D subsurface flows. The Richards equation is the physical model most used for single-phase, isothermal, variably saturated flow. It is a non-linear partial differential equation requiring numerical solutions which can be computationally expensive, specially in 3D domains where a large number of cells is necessary. In this work, a numerical model for the solution of the 3D Richards equation is presented. The scheme is built within the Finite Volumes framework and integrated implicitly in time. The implicit scheme is unconditionally stable in theory, though accuracy can suffer with large time steps. The model handles naturally dry or flooded conditions at the surface, as well as saturated or unsaturated conditions in the soil. The numerical scheme is shown to be mass conservative and accurate. It also degenerates easily into 2D and 1D models. Benchmarking is performed against 1D and 3D groundwater analytical solutions as well as experimental cases and synthetic test cases. By means of these tests the accuracy of the model is tested and efficiency is studied. Sensitivity to mesh resolution and structure is studied using hexahedral and tetrahedral cells. Sensitivity to time step size is also studied. Finally, the computational cost of the model is evaluated and the efficiency of different modeling choices is assessed.
File Size : 904,419 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 35th IAHR Congress - Chengdu (2013)
Date Published : 19/07/2016
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