Recently, the research team of Coastal and Estuarine Conservancy and Development published a research paper entitled “Wave-plus-current Induced Span Shoulder Migration in Three-Dimensional Scour Around Submarine Pipeline” in Coastal Engineering, a leading journal in the field of coastal engineering. The study was jointly conducted by renowned scholars from the Technical University of Denmark and the China National Offshore Petroleum Research Center, and Junior Prof. Sui TiTi of the team served as the first author, and Prof. Zhang Chi and Prof. Zheng Jinhai were the co-authors.
The phenomenon of overhanging span expansion of submarine pipelines due to the combined action of wave currents is one of the key factors leading to fatigue damage of pipelines, and thus has attracted extensive attention from the domestic and international coastal and ocean engineering communities. In this study, the mechanism of pipeline span expansion under wave current loading conditions is investigated in depth, and the “Pump Effect” of pipeline span expansion under the coexistence of wave currents is revealed, i.e., there is an obvious time intermittency between sediment transport under the pipeline and the span expansion process. This means that the sediment transport under the pipeline and the span expansion process have obvious temporal intermittency. This finding suggests that, when the wave component is taken into account, the span expansion rate of the pipeline slows down compared to a purely hydraulic environment, and that the relative strength of the flow velocity is the main factor influencing this change. Based on the magnitude analysis method, the research team proposed a new prediction model that reflects the effects of flow velocity strength, Shields number, and the depth of the pipe burial on the span expansion rate. The model is validated against 117 sets of experimental data, and the results show that the model performs well in predicting the span expansion rate under wave flow conditions, with a 63% improvement in the prediction accuracy (R² = 0.8) compared with the existing model.
Titi Sui, Qi Yang, Leon Heine Staunstrup, Stefan Carstensen, Jun Huang, Chi Zhang, Jinhai Zheng, David R. Fuhrman, Wave-plus-current induced span shoulder migration in three-dimensional scour around submarine pipeline, Coastal Engineering, 194, 2024, 104622.
https://doi.org/10.1016/j.coastaleng.2024.104622