Details

Autor(en) / Beteiligte

• Sarlin, Wladimir
• Morize, Cyprien
• Sauret, Alban
• Gondret, Philippe

Titel

Nonlinear regimes of tsunami waves generated by a granular collapse

Ist Teil von

• Journal of fluid mechanics, 2021-05, Vol.919, Article R6

Ort / Verlag

Cambridge, UK: Cambridge University Press

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Tsunami waves induced by landslides are a threat to human activities and safety along coastal areas. In this paper, we characterize experimentally the waves generated by the gravity-driven collapse of a dry granular column into water. Three nonlinear wave regimes are identified depending on the Froude number ${Fr}_f$ based on the ratio of the velocity of the advancing granular front and the velocity of linear gravity waves in shallow water: transient bores for large ${Fr}_f$, solitary waves for intermediate values of ${Fr}_f$, and nonlinear transition waves at small ${Fr}_f$. The wave amplitude relative to the water depth increases with ${Fr}_f$ in the three regimes but with different nonlinear scalings, and the relative wavelength is an increasing or decreasing function of ${Fr}_f$ depending on the wave regime. Two of these wave regimes are rationalized by considering that the advancing granular front acts as a vertical piston pushing the water, while the last one is found to be a transition from shallow- to deep-water conditions. The present modelling contributes to a better understanding of the rich hydrodynamics of the generated waves, with coastal risk assessment as practical applications.