A Riemann-based two-phase two-layer SPH method for simulating submarine landslide tsunamis

Abstract

Capturing dynamic water–soil variations and addressing water/soil boundary in numerical simulations of submarine landslide tsunamis remain major challenges. This study proposes a new two-phase two-layer Riemann-smoothed particle hydrodynamics (SPH) numerical model. In this model, the soil satisfies the Drucker–Prager yield criterion and water is treated as a weakly-compressible fluid. The SPH method based on a low-dissipation Riemann solver, is innovatively introduced into the mathematical framework of water–soil coupling to simulate the dynamic behaviors of two overlapping water and soil particle layers. The no-slip boundary treatment based on a one-sided Riemann format is proposed to achieve the water/soil–solid coupling in landslide simulations. The volume fraction is fully participated in the current SPH discretization process, and the Riemann solver is also applied to improve its calculation. Validations against two static and dynamic water–soil coupling cases demonstrate that present approach is effective. Then, the proposed model with different particle resolutions is further applied to explore the submarine landslide tsunamis under two different configurations. The landslide motions exhibit good agreement and convergence with experimental data, and dynamic water–soil evolutions during the landslide process are properly captured with reasonable dissipation control, which indicates the accuracy and usability of the current Riemann-based two-layer model.