Numerical study of wave interaction with armour layers using the resolved CFD-DEM coupling method

Coastal armour layers have been commonly used to protect coastal structures from wave erosion. Assessing the stability of armour layers under extreme wave loading is a challenge for engineering design. In this study, we propose a resolved CFD-DEM coupling procedure to study the interaction of waves and irregularly shaped armour units. This model is validated by comparing the numerical results and a flume wave erosion test. The wave surface profiles and wave pressure distribution are reliably reproduced in the simulation. This model can well capture the wave energy dissipation of irregular armour units. Further, wave erosion on two types of armour layers, the cuboid and Dolos armours, are studied in a full-scale prototype model. The motion of individual armour units and the localised failure process under wave impact is observed and analysed in the simulation. We also study the influence of armour shape on overtopping discharge, pressure distribution, and vortex structure. The CFD-DEM method provides an advanced numerical tool for stability analysis and risk assessment of armour layers under the wave impact.