On the Local Scour Around a Jacket Foundation under Bidirectional Flow Loading

Jacket structure is a new type of offshore wind turbine foundations with advantages for its lightweight construction, high stability, and suitability for various water depths. However, jacket foundations are often subjected to scouring caused by tidal flows, which can significantly affect the stability of offshore wind energy systems. Limited research has been conducted on the scour characteristics around the jacket foundation under bidirectional flow actions due to the structural complexity. To address this gap, this study performs physical model tests to investigate the effects of flow properties and foundation position on the scour around the jacket foundation. This study assesses the impact of a complex upper truss structure and finite pile height on scouring, in contrast to monopile and regularly arranged pile group foundations. It also analyzes the differences in scour characteristics between a monopile foundation and a jacket foundation subjected to identical bidirectional flow conditions. The impact of flow direction on the scour evolution is evaluated by comparing the scour characteristics under unidirectional and bidirectional flow actions with the same hydrodynamic conditions. The results indicate that the equilibrium scour depth increases with the flow strength and water depth, and reaching its maximum at a foundation angle of 30 degrees. Findings are of great significance for predicting the scour extent around the jacket foundation.