Numerical Modelling of Scour Around Coastal and Offshore Infrastructure

Scour around coastal and offshore infrastructure is a critical concern, influencing foundation stability, structural performance, and long-term safety under wave–current loading. Reliable scour prediction is essential for designing resilient foundations for offshore wind turbines, bridge piers, subsea pipelines, breakwaters, and coastal protection systems. While physical modelling has advanced understanding of sediment entrainment and bed–flow interactions, numerical modelling is increasingly used to predict scour under complex, transient hydrodynamic conditions. This review provides a comprehensive assessment of the principal numerical approaches currently used to simulate scour. Four major modelling frameworks are examined: single-phase Eulerian Computational Fluid Dynamics (CFD), two-phase Eulerian–Eulerian CFD, coupled CFD–Discrete Element Method (CFD–DEM) approaches, and mesh-free Smoothed Particle Hydrodynamics (SPH) including SPH–DEM. For each method, governing formulations, sediment-transport models, turbulence closures, bed-evolution treatment, and fluid–sediment coupling procedures are critically evaluated. The review identifies the key strengths and limitations of each approach and assesses their suitability across different scour regimes. Remaining numerical challenges are highlighted, together with future research directions aimed at improving the reliability, robustness, and engineering applicability of scour modelling. The comparative assessment is structured around the core dimensions of underlying assumptions and physical representation, sediment-transport and bed-evolution capabilities, fluid–sediment coupling and process resolution, validation maturity, computational requirements and scalability, and engineering applicability.