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Communication Dans Un Congrès Année : 2022

Modeling the generation of shallow water waves by the gravity-driven collapse of a granular column

Résumé

Tsunamis are among the most destructive natural disasters for human coastal settlements. While events generated by earthquakes are well known, several past or potential occurrences of high amplitude waves arising from large-scale landslides have also been reported in the last decades. The famous 1958 Lituya Bay tsunami, featuring the highest recorded wave runup of 524 m, is reminiscent of the need for understanding how these disasters arise, and relevant approach to this end is to model experimentally the landslide as a flow of granular materials [1]. Recently, the generation of impulse surface waves by the collapse of a rectangular granular column into water was investigated experimentally. The wave amplitude A was found to depend on the geometry of the column (height H_0 and width L_0) and on the water depth h_0 in a non trivial manner. The relative wave amplitude A=h0 was shown to be governed mainly by the global Froude number Fr_0 = (H_0/h_0)^(1/2) with a non negligible e ect of the aspect ratio of the column a = H_0/L_0 [2], but A = h_0 can also be related to the final immersed deposit [3]. We propose here a predictive model based on the scaling laws known for the spreading dynamics of a gravity-driven collapse of a granular column [5] and on the scaling laws recently identified for the shallow water wave generation by a granular piston [4]. We then compare the model to a large dataset of experiments. The model reproduces well the influence of each initial parameters H_0, L_0, and h_0, and gives an accurate prediction for shallow water waves. It allows to explain the main role played by the global Froude number Fr0 and the aspect ratio of the column, but also the  nal immersed deposit. These results provide a simpli ed, yet comprehensive, description of the generation of tsunamis begotten by large-scale landslides, rockfalls, or cliff collapses. 1. H. M. Fritz, F. Mohammed, and J. Yoo, Lituya Bay landslide impact generated mega-tsunami 50th anniversary, Pure Appl. Geophys. 166, 153 (2009) 2. M. Robbe-Saule, C. Morize, R. Hena , Y. Bertho, A. Sauret, and P. Gondret, Experimental investigation of tsunami waves generated by granular collapse into water, J. Fluid Mech. 907, A11 (2021) 3. M. Robbe-Saule, C. Morize, Y. Bertho, A. Sauret, A. Hildenbrand, and P. Gondret, From laboratory experiments to geophysical tsunamis generated by subaerial landslides, Sci. Rep. 11, 18437 (2021) 4. W. Sarlin, C. Morize, A. Sauret, and P. Gondret, Nonlinear regimes of tsunami waves generated by a granular collapse, J. Fluid Mech. 919, R6 (2021). 5. W. Sarlin, C. Morize, A. Sauret, and P. Gondret, Collapse dynamics of dry granular columns : From free-fall to quasistatic flow, Phys. Rev. E 104, 064904 (2021)
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Dates et versions

hal-04437735 , version 1 (04-02-2024)

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  • HAL Id : hal-04437735 , version 1

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Wladimir Sarlin, Cyprien Morize, Alban Sauret, Philippe Gondret. Modeling the generation of shallow water waves by the gravity-driven collapse of a granular column. Rencontre du Non-Linéaire, Mar 2022, Paris, France. ⟨hal-04437735⟩
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