Technical Notes

Resolved Simulation of a Granular-Fluid Flow with a Coupled SPH-DCDEM Model


Debris flows represent some of the most relevant phenomena in geomorphological events. Because of the potential destructiveness of such flows, they are the subject of a vast amount of research. This paper addresses the need for a numerical model applicable to granular-fluid mixtures featuring high spatial and temporal resolution, and thus capable of resolving the motion of individual particles, including all interparticle contacts. The DualSPHysics meshless numerical implementation based on smoothed particle hydrodynamics (SPH) is expanded with a distributed-contact discrete-element method (DCDEM) in order to explicitly solve the fluid and solid phases. The specific objective is to test the SPH-DCDEM approach by comparing its results with experimental data. An experimental setup for stony debris flows in a slit check dam is reproduced numerically, where solid material is introduced through a hopper, assuring a constant solid discharge for the considered time interval. With each sediment particle possibly undergoing several simultaneous contacts, thousands of time-evolving interactions are efficiently treated because of the model’s algorithmic structure and the HPC implementation of DualSPHysics. The results, composed of mainly retention curves, are in good agreement with the measurements, correctly reproducing the changes in efficiency with slit spacing and density.