Three-phase flow simulation of beach erosion induced by breaking solitary waves.

The article focuses on the application and validation of a three-phase (air, water, and sediment) computational-fluid-dynamics (CFD) model based on OpenFOAM to simulate beach erosion induced by breaking solitary waves. The model incorporates two-way coupling between fluid and sediment phases and was validated against experimental data, showing good agreement in surface elevation, pore pressure, and beach profile changes. The study reveals distinct hydrodynamic and sediment transport characteristics during the wave runup and rundown stages, with intense but short-duration sediment transport during runup and slower, longer-duration transport during rundown, resulting in comparable total sediment movement in both stages. Limitations discussed include underestimation of erosion depth on the foreshore, challenges in modeling pore-pressure gradients, and assumptions of uniform sediment grain size, suggesting areas for future model improvement.