Numerical simulation of waves generated by landslides using a multiple-fluid Navier–Stokes model

a r t i c l e i n f o This work reports on the application and experimental validation, for idealized geometries, of a multiple-fluid Navier–Stokes model of waves generated by rigid and deforming slides, with the purpose of improving predictive simulations of landslide tsunamis. In such simulations, the computational domain is divided into water, air, and slide regions, all treated as Newtonian fluids. For rigid slides, a penalty method allows for parts of the fluid domain to behave as a solid. With the latter method, the coupling between a rigid slide and water is implicitly computed (rather than specifying a known slide kinematics). Two different Volume of Fluid algorithms are tested for tracking interfaces between actual fluid regions. The simulated kinematics of a semi-elliptical block, moving down a water covered plane slope, is first compared to an earlier analytical solution. Results for the vertical fall of a rectangular block in water are then compared to earlier experimental results. Finally, more realistic simulations of two-and three-dimensional wedges sliding down an incline are compared to earlier experiments. Overall, in all cases, solid block velocities and free surface deformations are accurately reproduced in the model, provided that a sufficiently resolved discretization is used. The potential of the model is then illustrated on more complex scenarios involving waves caused by multi-block or deformable slides. Landslide generated impulse waves, also referred to as landslide tsunamis (Ward, 2001) are water waves created by mass flows, either initiated underwater or subaerial. Such waves may occur both in the ocean and in more restricted water bodies, such as lakes, reservoirs, or fjords. are among the main geophysical mechanisms responsible for landslide tsunami generation. In view of typical slide volumes, tsunami hazard in terms of coastal run-up is usually limited to the near-field generation area. However, recent studies (e.g., Masson et al. 2002, 2006; Pareschi et al., 2006) indicate that volcano collapses involving huge volumes (in the hundreds of km 3 of material) have occurred in the past, which could have the potential of triggering tsunamis large enough to strike coasts far away from the generation area, even over transoceanic distances) show that complex wave fields can be generated by underwater or subaerial slides. The correct description of these waves near the source is the key to the accurate modeling and prediction of tsunami propagation, resulting coastal hazard, and eventual mitigation. Due to the many spatial and …