Numerical simulation of wave scouring beneath marine pipeline using smoothed particle hydrodynamics

In this paper a smoothed particle hydrodynamics (SPH) approach is presented to simulate scouring due to wave around a marine pipeline on a sloping sea bed. The proposed method is similar to so-called SPH projection method and consists of three steps. The first two steps play the role of prediction, while in the third step a Poisson Equation is used for both fluid and sea bed to impose incompressibility constraint. It is assumed that the sandy sediments around pipeline section which represent the variable boundary and scour profile, behave as a non-Newtonian fluid. Therefore scouring below a pipe under waves in a test flume with a piston wave maker and sandy sloping bed is estimated using Newtonian – non Newtonian fluid flow interaction model. The Bingham Model is cautiously utilized for simulation of the sea bed behavior. Modeled results with or without viscosity were compared with analytical, empirical and experimental results and a reasonable agreement was found. Results show that the developed model is a powerful tool to simulate complex free surface and Newtonian – non Newtonian fluid interaction problems.