Vertically integrated numerical model to simulate breach formation by flow overtopping earth-filled dams: hydraulics

The simulation of earth-filled dam breach formation and the flood waves that are generated mainly involves three physical aspects: hydraulics, sediment transport, and slope stability. Herein, a numerical model capable of simulating the hydraulics of a flow overtopping an earth-filled dam is presented. The model is of the shallow-water type, obtained by the vertical integration of the incompressible free-surface Navier-Stokes equations, but without the usual assumptions of hydrostatic pressure and small slope. Different assumptions concerning velocity, pressure, and shear stress profiles are made in order to enhance the shallow water equations by including the geometrical effects (steep slopes), the dynamic pressure effects, and the shear-stress variation effects. Another important feature of the model is the capacity to capture flow regime changes (from sub-critical to super-critical and vice versa through a hydraulic jump) in a continuous way. A stabilized finite-element method is used to solve these equations and control the model. Results obtained for the simulation of overtopping flow are presented.