85 / 2025-04-24 12:55:52

2D or not 2D – That is the question: Equilibrium Scour Depths at Circular Piles for Steady Currents, Waves and Combined Wave-Current Conditions

Development of local erosion around circular foundations is an extensively studied topic with a broad application in hydraulic engineering. An often-used guideline in engineering practice for offshore wind turbine foundations is to assume an equilibrium scour depth of 1.3 times the pile diameter (with an optional added single or double standard deviation of 0.7 times the pile diameter). In this paper, we performed an extensive literature review for scour depths in different conditions (steady current, wave-only and combined wave-current) around circular piles. A total of ~600 datapoints were collected to cross-validate the statistic that forms the basis of engineering practice in offshore wind, the majority of the data associated with the live bed scour regime. With this data analysis we provide a re-parameterization of equilibrium scour depth prediction methods for various hydrodynamic conditions, primarily focusing on the mean scour depth.