Hydrodynamics of surface irrigation: vertical structure of the surge front

Abstract

A model for surface irrigation is developed that allows the determination of the vertical structure of the velocity profile in the vicinity of the wave front. The pressure is not assumed to be hydrostatically distributed and no assumptions are made regarding the shape of the freesurface profile. The turbulent kinetic energy and rate of dissipation are computed by a two-equation model and accurate determination of the bottom shear makes possible the analysis of particle suspension. The model is based on a two-dimensional finite element model in the vertical plane and uses the kinematic condition for determining the position of the free surface. It also incorporates a numerical technique for describing surface penetration and wave breaking by combining a Lagrangian approach that allows the computational nodes to move individually and then automatically reshapes the element grid. The potential value of the model lies in its ability to provide information on vertical mixing, settling and suspension of contaminated solids commonly found in irrigation applications.