HYDRODYNAMICS OF SURFACE IRRIGATION - VERTICAL STRUCTURE OF THE SURGEFRONT

A model for surface irrigation is developed that allows the determinat ion of the vertical structure of the velocity profile in the vicinity of the wave front. The pressure is not assumed to be hydrostatically d istributed and no assumptions are made regarding the shape of the free -surface profile. The turbulent kinetic energy and rate of dissipation are computed by a two-equation model and accurate determination of th e bottom shear makes possible the analysis of particle suspension. The model is based on a two-dimensional finite element model in the verti cal plane and uses the kinematic condition for determining the positio n of the free surface. It also incorporates a numerical technique for describing surface penetration and wave breaking by combining a Lagran gian 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 m ixing, settling and suspension of contaminated solids commonly found i n irrigation applications.