On the Numerical Analysis of Richard's Equationfor Modeling Flow in Unsaturated Soils

The flux of water in unsaturated soils plays an important role in analysis of hydraulic structures. In addition, water infiltration from the soil surface and flux through the soil column are important processes in hydrologic cycles, which they were predicted using the Richards’ equation. The objective of the present research was to apply a novel numerical technique called Localized Differential Quadrature Method (LDQM) for modeling water flow in unsaturated soils. Up to now, LDQM has been used in many investigations and has been claimed as highly accurate, stable and efficient method. The 1-D Richards’ equation was used as a simple mathematical model. At first, the governing equation and associated initial and boundary conditions were described. Then the implementation of the method for discretization of governing equations was discussed. An analytical solution data and experimental measurements were employed for evaluation of the results. It was concluded that, LDQM has high accuracy and efficiency. The application of the method for 2D and 3D cases is recommended for future researches.