Stability of breakwaters under hydrodynamic loading using a coupled DDA/FEM approach

In this paper, a numerical study is conducted to assess the stability of the seaward facing slope of breakwaters under hydrodynamic loading using a coupled fluid–structure interaction framework. Stability characteristics of breakwaters have traditionally been analysed using empirical approaches which do not take into account important factors such as non-linear wave–structure effects. A modelling framework is proposed for coupling discontinuous deformation analysis (DDA) with a finite element method (FEM) for solving free-surface flows where the Navier–Stokes equations are solved for velocity and pressure. It is necessary to take into account contacts between different shaped blocks and this study assumes that contact constraints are imposed through an augmented Lagrangian algorithm. To illustrate the performance of the proposed framework two breakwaters consisting of cubic and acropod shaped blocks are simulated under hydrodynamic forces.

► A numerical study is conducted to assess the stability of breakwaters under hydrodynamic loading.
► A framework is proposed for coupling DDA with a FEM for solving free-surface flows.
► It has been found that the shape of the blocks play an important role in the stability of breakwaters.
► For acropod shaped blocks, contacts assist in the dissipation of wave energy which contributes in the stability.
► The non-hydrostatic pressure in the fluid flow formulation takes into account additional sudden impulsive.