Wave-current interaction effects on monopile scour using three-phase eulerian model

Scour around monopile foundations is a primary design driver for offshore wind assets because seabed erosion can compromise geotechnical capacity, inflate maintenance, and shorten design life (Sumer and Fredsøe 2002). Scour arises from flow separation, an upstream horseshoe vortex, and lee‑side wake vortices that elevate near‑bed shear and entrain sediment (Roulund et al. 2005). Offshore sites rarely experience current‑only conditions; combined waves and currents modulate vortex strength and persistence, producing scour geometries that differ from steady currents.
A consistent trend in flume studies is that co‑directional wave–current forcing intensifies horseshoe vortices and deepens scour, whereas opposing waves weaken phase‑averaged near‑bed flow and reduce scour extent (Sumer and Fredsøe 2001; Qi and Gao 2014). This work presented in this abstract examines these mechanisms with a three‑phase Eulerian CFD approach, focusing on how alignment (current‑only, co‑directional, opposing) controls sediment transport, vortex dynamics, bed shear, and the resulting scour shape.