The effects of dispersion and non-linearity on the simulation of landslide-generated waves using the reduced two-layer non-hydrostatic model

Abstract

This paper revisits the previously developed NH-2LR (reduced two-layer non-hydrostatic) model. The governing equations and numerical schemes are written in terms of normalized variables, with two dimensionless parameters representing dispersion and non-linearity. By utilizing analytical solutions and laboratory experiments, this study aims to validate the numerical NH-2LR model and investigate the effects of dispersion and non-linearity on the resulting waves. The first validation employs the analytical solution of the linear and fully dispersive model of a landslide moving with constant velocity on a flat bottom. The second validation involves a landslide hump sliding over a constant beach slope. A closer look at the run-up height reveals that this case is non-dispersive. Furthermore, we found that the dispersion effect was evident from the beginning of the wave formation process. Finally, we compare our numerical results to experiments on submarine landslides on sloping beaches. We found that dispersion is essential in the early generation and propagation of waves in off-shore regions. Moreover, non-linearity significantly influences the maximum run-up of landslide-generated waves.