Numerical simulation on the movement behavior of viscous submarine landslide based on coupled computational fluid dynamics-discrete element method

Submarine landslide is one of the main marine geological disasters. Once submarine slide happens, it will cause serious damage to underwater infrastructures. However, there are few researches on the movement and evolution of submarine landslides, especially considering the viscous effect of submarine landslides. A fluid-structure coupling model describing the interaction between water and particles was established by using computational fluid dynamics (CFD) and discrete element method (DEM), and a cohesive force model was introduced to develop a coupled CFD-DEM analysis method considering the viscous characteristics of sliding body. On this basis, the kinematic characteristics (velocity and distance) and morphological characteristics (length, width, shape, etc.) of the submarine landslide were systematically simulated by considering the viscosity and initial velocity of the landslide, and the influencing mechanism of the evolution process of the landslide movement was investigated in depth. The results show that the coupled method can simulate and reproduce the small-scale movement behavior of the submarine landslide well, the viscous action of the landslide has a remarkable influence on its kinematic and morphological characteristics, and the initial velocity also significantly affects the evolution and distribution characteristics of the particle flow field in each part of the landslide. The results can provide a scientific basis for the evolution process simulation and the effective prediction of submarine landslides.