Sediment Transportation Mechanism Around Submarine Pipelines on a Slope Seabed

Coupled numerical models based on CFD and DEM were developed to analyze the interaction between fluid flow and sediment particles. To enhance simulation efficiency and accuracy, a series of methods were proposed, validated, and applied, including the single‐phase oscillation method, the coarse‐grained method, the porous medium replacement strategy, and a semi‐resolved approach. Numerical simulations were performed to investigate the scour process around a submarine pipeline situated on a slope, specifically examining the effects of slope angle, pipeline suspension height, and wave height. The flow field, forces acting on particles, and particle movement patterns were analyzed. Results indicate that while the slope angle significantly affects the flow pattern, it exerts limited influence on hydrodynamic forces. The decomposition of gravity into components alters the force balance on particles, rendering them more vulnerable to erosion and facilitating downslope transport under wave action.