Fully coupled formulation of surface flow with 2-phase subsurface flow for hydrological simulation

With the aim of realizing a surface-subsurface-coupled fluid flow simulation, the authors discuss surface flow models that can be used in the framework of the 2-phase subsurface numerical simulation system. In this paper, three surface flow models, i.e., a kinematic wave model (KW), a diffusion wave model (DW), and a linearized diffusion wave model (LDW), are explained by approximating the momentum equation, and are transformed into a set of nonlinear functions which can be solved simultaneously with the 2-phase subsurface flow. By incorporating these into a 2-phase numerical simulation system, comparison studies are carried out using experimental data and a field scale model. So far as the results of the study are concerned, it is concluded that the DW model gives reasonable performance for any case, the LDW model provides mostly identical results with the DW model with some restrictions, while the KW model is not applicable for the physical modelling of continuous flow through multiple slopes with different angles. Copyright © 2000 John Wiley & Sons, Ltd.