A novel rigid-fluid method for landslide tsunami modeling

This study presents a three-dimensional numerical model with the novel rigid fluid method (RFM) to simulate slide-type landslides. RFM, coupled with the Navier–Stokes solver Splash3D, is developed to calculate the movement and rotation of a moving solid. With the pressure and shear stress data in each grid collected by the discrete element method, the moving solid is granted to be involved in the simulation. The model is validated against a three-dimensional experiment of a sphere entering water, demonstrating good agreement in terms of displacement and air column pinch-off time. Subsequently, the model is applied to simulate the process of a semispherical landslide tsunami, using a semispherical laboratory experiment as a benchmark. The numerical results show excellent agreement with the experimental data in terms of sliding track, velocity, dynamic pressure, and wave height. To investigate the applicability of the model to real-world scale events, the above-mentioned case is scaled up proportionally, and the time, flow velocity, dynamic pressure, and resultant force are compared to verify the Froude number similarity. The results indicate that the model can effectively capture the essential features of landslide-induce tsunamis and has the potential to be used for further studies on the impacts of such events.