Two-fluid smoothed particle hydrodynamics simulation of submerged granular column collapse

•A two-fluid smoothed particle hydrodynamics (SPH) model, based on the mixture theory, is developed.•A re-initialization technique is developed and an alternative treatment of the pressure term is proposed.•Two regimes of the collapse of submerged granular column are identified and the key factors are analyzed.•Numerical simulations demonstrate the capability of the proposed approach in dealing with saturated water-soil mixture flows.

In this paper, a two-fluid smoothed particle hydrodynamics (SPH) model, based on the mixture theory, is employed to investigate the complex interactions between the solid particles and the ambient water during the process of submerged granular column collapse. From the simulation, two regimes of the collapse, one being quick and the other being slow, are identified and the reasons of formation are analyzed. It is found that, a large internal friction angle of the granular phase, representing large drag force between solid particles, helps form the slow regime. Small hydraulic conductivity, representing large inter-phase drag force, also retards the collapse dramatically. Good agreements between our numerical results and other researchers' numerical and experimental results are observed, which demonstrates the capability of the proposed two-fluid SPH approach in dealing with saturated water-soil mixture flows.