A Coupled PFEM-DEM Model for Fluid-Granular Flows with Free-Surface Dynamics Applied to Landslides

TL;DR

This paper introduces a coupled PFEM-DEM simulation framework for modeling fluid-granular flows with free surfaces, effectively capturing complex interactions and interface evolutions in phenomena like landslides and dam failures.

Contribution

It presents a novel integrated numerical approach combining PFEM and DEM for accurate simulation of fluid-granular flows with free-surface dynamics, validated on benchmark and real-world cases.

Findings

Successfully simulates landslides and dam failures

Captures complex fluid-granular interactions

Handles deforming free surfaces effectively

Abstract

Free surface and granular fluid mechanics problems combine the challenges of fluid dynamics with aspects of granular behaviour. This type of problem is particularly relevant in contexts such as the flow of sediments in rivers, the movement of granular soils in reservoirs, or the interactions between a fluid and granular materials in industrial processes such as silos. The numerical simulation of these phenomena is challenging because the solution depends not only on the multiple phases that strongly interact with each other, but also on the need to describe the geometric evolution of the different interfaces. This paper presents an approach to the simulation of fluid-granular phenomena involving strongly deforming free surfaces. The Discrete Element Method (DEM) is combined with the Particle Finite Element Method (PFEM) and the fluid-grain interface is treated by a two-way coupling between the two phases. The fluid-air interface is solved by a free surface model. The geometric and topological variations are therefore naturally provided by the full Lagrangian description of all phases. The approach is validated on benchmark test cases such as two-phase dam failures and then applied to a real landslide problem.