Session: 06-02-02 Coastal Engineering - II

Submission Number: 181995

A Fully Resolved CFD-DEM Framework for Debris Entrainment Due to Tsunami-Like Flows 

Accurate prediction of debris motion and impact loads during tsunami bores and dam-break floods requires numerical tools that resolve both the free-surface flow field, its dynamics and the complex interactions among multiple large bodies. In this study, a fully resolved coupled CFD-DEM framework is implemented in REEF3D to simulate multiphase flows on a fixed Cartesian grid. The method couples a high-order hydrodynamic solver, a level-set free-surface model, a Direct Forcing Immersed Boundary Method (DF-IBM), and 6DOF rigid body dynamics. Inter-body and body-wall interactions are treated using a multi-stage collision detection pipeline. The collision algorithm, based on a linear viscoelastic spring-dashpot model, ensures two-way coupling between hydrodynamic forces, collision forces, and rigid body motion.
The framework is first validated against the benchmark case of a rigid sphere settling in a confined container at a moderate Reynolds number. The numerical results show excellent agreement with the experimental data for both the trajectory and the settling velocity. The model is then applied to a three-dimensional dam-break scenario involving two rows of container-like cuboid debris to investigate entrainment and collisions under extreme flow conditions. The simulation resolves debris shielding effects and collision sequences during bore impact. Overall, the results demonstrate that the proposed CFD-DEM framework provides a high-fidelity tool for analyzing debris-wave interactions and supports improved hazard assessment and load estimation in tsunami-like environments.

Presenting Author: Elyas Larkermani Norwegian University of Science and Technology

Presenting Author Biography: Elyas Larkermani is a Postdoctoral Researcher in the Department of Civil and Environmental Engineering at the Norwegian University of Science and Technology (NTNU). He received his PhD from NTNU, where his research focused on high-fidelity simulations of indoor airflow using the Immersed Boundary Method and Large Eddy Simulation. His current work involves coupling Computational Fluid Dynamics with Discrete Element Methods for simulating rigid body interactions in marine environments. His research interests include multiphase flow, turbulence modeling, and numerical methods for environmental fluid mechanics.

Authors:

Elyas Larkermani Norwegian University of Science and Technology
Nils Goseberg Technische Universität Braunschweig
Hans Bihs Norwegian University of Science and Technology