Variable-resolution DualSPHysics modelling of a perforated wall breakwater: preliminary 2D results

This paper presents a preliminary two-dimensional (2D) numerical study of wave interaction with a perforated wall breakwater using the DualSPHysics model, incorporating variable resolution (vres) and modified dynamic boundary conditions (mDBC). The vres approach enables finer particle spacing near the structure while using coarser spacing elsewhere, reducing the total particle number by a factor of over 20 compared to a uniformly fine resolution. Simulation results reveal complex flow behaviour, including a sloshing-like secondary wave and an unexpected increase in transmitted wave height, attributed to the damming effect and/or numerical artefacts in the resolution transition zones. A still water test confirms the emergence of unphysical flow patterns near nested regions, indicating potential instability in the current zone configuration. These findings highlight key challenges in applying vres to detailed coastal simulations. Nonetheless, this study demonstrates the potential of advanced SPH techniques to model innovative breakwater designs more efficiently, supporting the development of resilient and sustainable coastal infrastructure.