Laboratory modeling study on the scour characteristics around a jacket foundation subjected to combined wave-current loading
Hao Chen, Jisheng Zhang, Yakun Guo, Lin Cui, Dawei Guan, Lai Jiang
Abstract
This paper presents the experimental results to investigate the scour around a jacket foundation under the combined wave-current loading. Under such complicated hydrodynamic action, sediment transport and the resultant scour evolution around the jacket foundations are extremely complex compared to that around monopile foundations. This study investigates the effects of wave-current parameters, including flow strength and Keulegan–Carpenter number ( K C ), on the local scour characteristics around a jacket foundation through comprehensive laboratory experiments. The effect of the relative wave-current velocity ( U c w ) on the clear-water and live-bed scours are examined. Results indicate that the scour pattern is dominated by the current and the jacket piles are surrounded by inverted-cone scour pit when U c w exceeds 0.49 in this study. When U c w is less than 0.49, the piles are surrounded by concentric circular scour pit. The relative scour depth, normalized by the pile diameter, increases linearly with the increase of K C number for a constant flow strength. However, the growth rate of the equilibrium scour depth decreases with the increase of flow strength. Fluctuations of the maximum scour depth with the Shields parameter θ and the Froude number F r a are also investigated.