Oscillatory responses of a spatially random seabed in the vicinity of structures: Validation and application of the integrated CFD-SFEM

A comprehensive examination of the wave-induced oscillatory response of seabeds around structures is of great significance for ensuring the safe operation of marine engineering projects and enhancing the efficiency of marine resource development. Soil properties in nature exhibit spatial variability due to various geological processes, which should be considered in seabed stability analysis. An integrated CFD-SFEM is proposed for spatially heterogeneous seabeds, incorporating multi-physical solvers for nonlinear wave motion and poroelastic seabed response within a unified framework through a one-way coupling procedure. The wave sub-model for nonlinear fluid flow is based on RANS equations, with an internal wave-maker and absorbing layers realized by employing a momentum source function and damping source terms. The spatially heterogeneous seabed sub-model is based on Biot's poroelastic theory and the random field method. We have implemented the integrated model and automated the iterative algorithm for MCS using MATLAB codes, assisted by the LiveLink platform. The proposed method has been validated from various perspectives and applied to a study of soil response around a partially buried pipeline to demonstrate its practical utility. This study offers a novel framework and perspective for the probabilistic evaluation of oscillatory responses in spatially varied seabeds surrounding structures.