Study of wave-induced seabed response around twin pipelines in sandy seabed through laboratory experiments and numerical simulations

Wave-seabed-pipelines interaction is of critical importance in the design of submarine pipelines. Previous studies mainly focus on investigating the characteristics of flow fields and hydrodynamics around a single pipeline. In this study, laboratory experiments and numerical simulations have been performed to examine the effect of burial depth and space between the centers of twin pipelines on the wave-seabed-twin pipelines interaction subject to waves. In the mathematical model, the Volume-Averaged Reynolds-Averaged Navier-Stokes (VARANS) equations are used to describe the wave motion in the fluid domain, while the seabed domain is described by using the Biot's poro-elastic theory. Numerical models are validated using these experimental measurements and available relevant experimental data. Experimental and numerical results indicate that the burial depth and relative position of twin pipelines can significantly affect the wave-averaged flow velocity field and the pore-water pressure distribution as well as effective stress.