Dynamics of landslide-generated tsunamis and their dependence on the particle concentration of initial release mass

• Published in: European journal of mechanics, B, Fluids Vol. 97; pp. 146 - 161
• Main Authors: Kafle, Jeevan, Dangol, Bekha Ratna, Tiwari, Chet Nath, Kattel, Parameshwari
• Format: Journal Article
• Language: English
• Published: Elsevier Masson SAS 01.01.2023
• Subjects: Landslide-induced tsunami; Particle concentration of release mass; Subaerial landslides; Submarine mass movement; Two-phase mass flows; Submarine mass movement; Subaerial landslides; Landslide-induced tsunami; Particle concentration of release mass; Two-phase mass flows
• ISSN: 0997-7546; 1873-7390
• DOI: 10.1016/j.euromechflu.2022.10.003

Tsunamis are impulse water waves generated at the moment when rapidly moving landslide or any other gravitational mass strikes a water reservoir by transforming its impact energy to the water body. The propagation of resulting water waves might cause damages and casualties nearby field as well as in farther coast. The destructive effects caused by the landslide-generated impulsive waves can be significantly affected by the characteristics of channel geometry and particle concentration of initial mass. Experimental and computational models have been substantially applied to study the dynamics of these complicated natural events. Using a general two-phase mass flow model, we conduct various numerical experiments and then illustrate the high-resolution simulated results in geometrically three-dimensional framework for time evolution of both solid and fluid wave structures with varying concentrations of the two-phase initial release mass. The results reveal that amplitudes of tsunami and the run-out extents are quickly expanding along down-slope and cross-slope when the solid concentration of initial landslide mass is increased. The concentration of grains in the release mass significantly affects the flow dynamics and fluid waves when the flow hits a still reservoir downstream. The outcomes indicate that the numerical modeling using advanced governing equations, and integrated simulation techniques can be used to assess the different geophysical mass flow dynamics such as granular flow, debris flow, mud flow, and flash flood as well as GLOF and the dynamics of water waves and submarine flow after the flow-reservoir-interaction. The study of the influence of the particle concentration of initial landslide mass can be applicable to mitigate the hazards caused by tsunamis and submarine mass movements. •Employed a two-phase mass flow model to study landslide motion, wave dynamics.•Higher solid concentration creates more intensified and quicker tsunami propagation.•Fluid-rich flow poses a lower risk at the front but a higher risk at lateral boundaries.•Mixture flow is more elongated, less dispersed downslope for solid-rich lateral edges.•Flow and wave dynamics as simulated here are useful for risk assessments.