Multiresolution Multiphase Modeling of Giant Landslide-Dammed Lake Breaching-Outburst Flood Disaster Chains

Giant landslides and debris flows in mountainous regions, exacerbated by climate change, frequently form landslide-dammed lakes whose breaching can trigger catastrophic outburst floods. Current understanding relies heavily on post-event field investigations, laboratory experiments, and continuum-based simulations, leaving the multiphase dynamics of fluid–debris interactions across scales poorly quantified. To address this, we develop a novel multiresolution coupled Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) framework capable of simulating the entire disaster chain—from landslide motion and dam formation to overtopping failure and flood propagation. The framework integrates resolved, unresolved, and hybrid resolution schemes to capture multiscale particulate systems efficiently. Real-world topography and irregularly shaped grains (from gravel to boulders) are directly incorporated via STL files. Computational efficiency is enhanced through GPU acceleration and adaptive mesh refinement, enabling large‑scale simulations. In a preliminary test simulating a 2.9 km × 2.8 km × 0.8 km domain with approximately 1.5 million polydisperse particles, 500 s of real‑time dynamics were computed in 25 hours using an RTX 5090, demonstrating the framework’s capability to model full‑scale disaster chains with complex fluid–solid coupling. This work provides a quantitatively accurate tool for assessing disaster progression and hazard potential, representing a significant advance in geohazard modeling with broader applicability to multiscale, multiphase particulate systems in engineering and environmental sciences. Acknowledgement: This research was supported by the NSFC Young Scientists Fund (Type C, No. 52508410).

Figure 1 Multiresolution CFD-DEM modeling of landslide-dammed lake breaching-outburst flood disaster chains