Numerical investigation of local scour around a vibrating pipeline under steady currents

Abstract

A two-dimensional finite element numerical model was developed to predict local scour around a vibration submarine pipeline in steady current. The numerical model was based on incompressible two-dimensional Navier-Stokes equations with a Shear-Stress Transport (SST) k-ω turbulence model closure. The transportations of suspended load and the bed load were taken into consideration in the present numerical simulation. The moving boundaries induced by the vibration pipeline and the evolution of the seabed due to local scour were tracked by using the Arbitrary Lagrangian Eulerian (ALE) method. Comparisons between the numerical results and available experimental data showed satisfactory agreements. The local scour around a vibrating pipeline has been investigated, including the maximum scour depth below the pipeline, the vortex shedding mode and the vibration amplitude of the pipeline. The numerical results showed that the maximum vibration amplitude of the pipeline could be about 1.2D, and the maximum scour depth occurred in the wake side of the vibration pipeline.