Numerical modelling of armour block sea breakwater with smoothed particle hydrodynamics

• SPH to model the interaction of waves with a rubble mound breakwater is presented.
• Fluid–structure interaction is modelled with particles representing a real structure.
• The layout of the Zeebrugge antifer breakwater is numerically reproduced in detail.
• The capability of SPH model to simulate wave run-up on this rough structure is shown.
• A good agreement is shown comparing numerical with theoretical solutions and experimental results.
• It is a first successful approach in modelling this phenomenon with a meshless model.

The application of smoothed particle hydrodynamics (SPH) to model the three-dimensional fluid–structure interaction for waves approaching a rubble mound breakwater is presented. The main aim is to model the armoured structure and to validate its response under the action of periodic waves. The complex geometry is represented by grooved cubic blocks such that the surrounding gaps within the breakwater seaward layer require a large number of particles to obtain a sufficiently detailed description of the flow. Using novel computer architecture solutions such as graphics processing units (GPUs), the fluid-structure interaction is modelled with SPH particles between armour blocks that are representative of the real structure. The open-source GPU code, DualSPHysics, enables the simulation of millions of particles required for the accurate simulation of the run-up on an armoured structure. SPH has been proven to be a suitable method for practical applications in coastal engineering. In the present work the run-up heights are computed and compared with empirical solutions and experimental data. Reasonable agreement is obtained for the run-up due to regular waves over a range of surf similarity numbers from 3.0 to 5.5.