Numerical Simulations of Tsunami Wave Generation by Submarine and Aerial Landslides Using RANS and SPH Models

Abstract

Tsunami wave generation by submarine and aerial landslides is examined in this paper. Two different two-dimensional numerical methods have been used to simulate the time histories of fluid motion, free surface deformation, shoreline movement, and wave runup from tsunami waves generated by aerial and submarine landslides. The first approach is based on the Navier-Stokes equation and the volume of fluid (VOF) method: the Reynolds Averaged Navier-Stokes (RANS)-based turbulence model simulates turbulence, and the VOF method tracks the free surface locations. The second method uses Smoothed Particle Hydrodynamics (SPH)—a numerical model based on a fully Lagrangian approach. In the current work, two-dimensional numerical simulations are carried out for a freely falling wedge representing the landslide and subsequent wave generations. Numerical simulations for the landslide-driven tsunami waves have been performed with different values of landslide material densities. Numerical results obtained from both approaches are compared with experimental data. Simulated results for both aerial and submerged landslides show the complex flow patterns in terms of the velocity field, shoreline evolution, and free-surface profiles. Flows are found to be strongly transient, rotational, and turbulent. Predicted numerical results for time histories of free-surface fluctuations and the runup/rundown at various locations are in good agreement with the available experimental data. The similarity and discrepancy between the solutions obtained by the two approaches are explored and discussed.

Tangjiaxi Landslide and Impulse Wave Analysis in Zhexi Reservoir of China by Granular Flow Coupling Model

“…In particular, the RNG model is known to describe low intensity turbulence flows and flows having strong shear regions more accurately. The RNG model selected has already been successfully used to simulate impulse wave generated by landslides (Serrano-Pacheco et al 2009;Basu et al 2009;Das et al 2009;Choi et al 2007). (Fig.…”

“…Some landslides are simplified as rigid bodies whose motion is mainly described with Newton's law of motion under gravity, friction, coupled water resistance, etc. (Das et al, 2009;Basu et al, 2009;Huang et al, 2013). For example, Yin et al(2014) simulated the motion of Qianjiangping landslide as a rigid rotator and coupling calculated the impulse waves.…”

The 1958 Lituya Bay tsunami – pre-event bathymetry reconstruction and 3D numerical modelling utilising the computational fluid dynamics software Flow-3D

“…Recently, the most used commercially available software to model impulse waves is the computational fluid dynamics (CFD) model Flow-3D, which is based on a threedimensional numerical modelling approach (Das et al, 2009;Vasquez, 2017). The objective of this study is to test the capacity and limits of Flow-3D by means of reconstructing a landslide-generated impulse wave on a large spatial scale.…”

Analysis of the Tangjiaxi landslide-generated waves in the Zhexi Reservoir, China, by a granular flow coupling model

“…In particular, the RNG model is known to describe lowintensity turbulence flows and flows having strong shear regions more accurately. The RNG model selected has already been successfully used to simulate impulse waves generated by landslides (Serrano-Pacheco et al, 2009;Basu et al, 2009;Das et al, 2009;Choi et al, 2007). (Du, 1988).…”