Numerical study of landslide-induced surge waves based on the volume of fluid–discrete element method coupling method

Landslide-induced surge waves involve complex fluid–solid interactions, making accurate and efficient numerical simulation methods crucial. This study proposes a volume of fluid–discrete element method (VOF–DEM) coupling method, in which the VOF method is embedded within a two-way-coupled computational fluid dynamics–DEM framework. Turbulence is modeled using a Reynolds-stress model, extending the approach to particle-laden, turbulent free-surface flows. In parallel, a virtual dual-mesh porosity algorithm is introduced to compute local fluid porosity with high accuracy. The coupled method is validated by comparing simulated particle column collapses with experiments results. The findings demonstrate that the method effectively captures landslide downslope velocity, surge waveform evolution, propagation characteristics, and deposition morphology. Applied to the RongSong deposit landslide at the RuMei Hydropower Station, the simulation successfully reproduces the landslide motion and surge waves generation and propagation. The results provide reliable physical insights for predicting and mitigating landslide-induced surge waves hazards in mountainous reservoirs.