Numerical investigation of scour around monopile foundation of offshore wind farm

Local scour at the foot of monopile foundations is a major threat to the stability of offshore wind farms. This study presents a 3D numerical model to investigate the local scour around monopile foundations considering the influence of both flow velocity and particle size. The Reynolds-Averaged Navier-Stokes (RANS) equations with the Renormalization Group (RNG) k-epsilon (k - epsilon) turbulence model were coupled with a sediment transport model to simulate the flow-sediment interaction process. The results reveal that the maximum scour depth and the extent of the scour footprint increase with flow velocity and decrease with particle size. The scour rate is higher for finer sediments than for coarser sediments. The scour depth and footprint reach a plateau when the particle size is larger than a certain critical value. The critical particle size increases with the increase of flow velocity. How scour depth formation is dependent on the sediment size and flow velocity. The increase and decrease in flow velocity increased the shear stress applied to the bed and thereby affecting scouring. A change in the period in all scenarios has a significant effect on scour depth.