Experimental investigation of tsunami waves generated by granular collapse into water

Abstract

Abstract

Nonlinear regimes of tsunami waves generated by a granular collapse

“…At large Fr 0 , strong asymmetric waves are generated with the shape of transient positive surges or bores, as shown in figure 2(a). The wave generated systematically breaks in the near-field region, and corresponds to the plunging breaker reported in Robbe-Saule et al (2021). At moderate Fr 0 , quasi-symmetrical waves are generated, consisting of a unique main pulse of soliton-like shape, as reported in figure 2(b).…”

“…However, granular materials must be considered to account for the complex landslide motion and interplay with the water. By studying the entry of grains into water at high velocity from a pneumatically launched box along a smooth inclined plane, Fritz, Hager & Minor (2004) observed different wave regimes depending on the Froude number Fr and slide thickness S: (i) transient (breaking) bores at high Fr and S; (ii) solitary-like waves at moderate Fr and S; (iii) nonlinear transition waves at low Fr and S; and (iv) weakly nonlinear oscillatory waves at very low Fr and S. Robbe-Saule et al (2017) have considered the experimental gravity-driven collapse of a subaerial granular column into water. They have shown that the aspect ratio and the volume of the granular column both play an important role on the amplitude of the wave generated.…”

“…With a similar but larger set-up, Huang et al (2020) observed the first three wave regimes reported by Fritz et al (2004), again depending on the aspect ratio and volume of the column. Recently, Robbe-Saule et al (2021) have shown that the local Froude number Fr f based on the horizontal velocity v f of the granular front at the water surface is the relevant parameter that governs the generation of the wave. However, a theoretical framework that accounts for the different wave regimes observed experimentally remains elusive.…”

Wave Generation Across a Continuum of Landslide Conditions From the Collapse of Partially Submerged to Fully Submerged Granular Columns

“…A landslide‐generated tsunami is formed by the momentum transfer between the sliding and deforming permeable body and the ambient fluid at the time the wave is released from the slide (Mulligan & Take, 2017), propagating out of the near‐field region. Previous studies on landslide induced waves have been conducted on either subaerial or submarine landslides, and focused on the common initial and boundary conditions of each process, that is, the slope angle, velocity, thickness, density, water depth (Fritz et al., 2003b, 2004; Heller & Hager, 2010; Heller et al., 2008; Mulligan & Take, 2017; Robbe‐Saule, 2019; Robbe‐Saule et al., 2021). In cases of both submarine and subaerial landslides, the geometry and kinematics of the moving mass at impact define the resultant maximum wave amplitude.…”

Falling jet of dry granular material in water

“…In this situation, tsunami waves can be generated by the entry of the granular mass into the ocean, which leads to a significant hazard for the population. This phenomenon has been the subject of experimental work to quantify the amplitude of the waves resulting from these events (Fritz, Hager & Minor 2003;Heller, Hager & Minor 2008;Viroulet, Sauret & Kimmoun 2014;Robbe-Saule et al 2021). Macroscopic theoretical models describing the energy transfer between the grains and the liquid have been proposed to predict the amplitude of the wave generated (Zitti et al 2016;Mulligan & Take 2017).…”