A Coupled Numerical Model for Tsunamis Generated by Subaerial and Submarine Mass Failures

This paper presents a new numerical model simulating tsunamis generation by landslides. Water, air, and the slide (considered either as a viscous fluid or as a rigid bloc using the penalization method) are described by Navier-Stokes equations, expressed in a unified single fluid approach. The PLIC-VOF method is used to describe the motion of fluid interfaces. We present results for two test cases featuring solid blocks. The first one is that of a semi-elliptical body sliding over a plane slope, without surrounding water. We find, the slide motion is accurately reproduced by the model when the slide viscosity is around 10 Pa.s. For larger viscosity values, the conditioning of the matrix associated with the Navier-Stokes solver is degraded. In the second case, a falling rectangular block generates waves in a flume. We find, wave height and box velocity are in agreement with experiments by Monaghan and Kos (2000). The simulated flow close to the falling box is similar to that observed in experiment, except that the observed main plunging wave and associated air entrainment.do not occur. In future work, the model thus validated will be applied to simulate more realistic cases of tsunamis generated by subaerial landslides.