Numerical Simulation of Submarine Landslides and Their Hydraulic Effects

Abstract

The submarine flow slides and their hydraulic effects are studied by numerical means. These types of landslides are assumed to separate into a dense flow close to the bed and a turbulent dispersion above it. A two-dimensional fluid mechanics mixture model based on Navier-Stokes' equations has been developed to study water waves generated by these landslides. The dense part is considered as a viscoplastic fluid, whereas the dispersed part is modeled by an ideal fluid. The rheological parameters of the model comprise a diffusion coefficient, a Bingham yield stress, a viscosity coefficient, and friction on the slope. First, the numerical model is validated with an analytical solution for a viscous and a Bingham flow. Then, it has been tested for a rigid box sliding into water along an inclined plane. The results of this simulation have been compared with experiments conducted in a channel. Finally, laboratory experiments consisting in the slide of a gravel mass have been carried out. The results of these experiments have shown the importance of the sediment rheology and the diffusion. The model parameters are adjusted by trial and error to match the observed “landslide” flow.