Numerical Analysis of Scour Characteristics around Offshore Wind Sub-Structures under Bidirectional Waves Conditions

Offshore wind sub-structures are exposed to scour risks under various flow conditions, with scour characteristics, especially in response to wave conditions, critically impacting structural stability. This study aims to quantitatively analyze the influence of unidirectional and Bidirectional wave conditions on the scour characteristics around the offshore wind sub-structures. Using the FLOW-3D, a comparative analysis of flow and scour characteristics was conducted under both unidirectional and Bidirectional wave conditions. In unidirectional wave conditions, It was found that flow tended to concentrate around the sub-structure, resulting in rapid scour development and deeper scour depths according to the maximum bottom velocity characteristics. Conversely, Bidirectional wave conditions generated intersecting flow patterns, dispersing the velocity around the structure, which mitigated scour and established a more stable flow regime. These findings highlight that variations in wave direction significantly impact flow and scour characteristics the offshore wind sub-structures, emphasizing the importance of considering effects of the attack angle in scour predictions for design and maintenance stages, respectively. The results of this study provide foundational data for predicting scour characteristics and evaluating the safety of offshore wind sub-structures under diverse wave conditions. This study serves as an essential reference for developing scour mitigation and maintenance strategies in complex marine environments.