Nonhydrostatic Model for Surface Irrigation

A nonhydrostatic model for overland flow is developed for the purpose of providing the framework for predicting the fate and transport of chemicals under surface irrigation. The technique is based on the turbulent Navier-Stokes equations for the surface wave and the Richards equation for the movement of moisture in the underlying porous medium. The model consists of a novel two-dimensional combination of the marker-and-cell and finite-element methods and utilizes a deforming computational grid that automatically adapts to moving wave fronts in the solution. Convergence and conservation tests are performed to demonstrate the robustness of the model. Results are presented for laminar and turbulent flow cases and compared to similar computations based on traditional depth-averaged models.