A weakly-compressible SPH-porous media model to simulate wave–breakwater interactions

This study introduces a weakly-compressible Smoothed Particle Hydrodynamics (SPH) model for accurately simulating free-surface flows and wave interactions with permeable breakwaters. Using mixture theory and the intrinsic phase-averaging method, we integrate the porous media constitutive law into the fluid flow solver, allowing SPH particles to dynamically adjust their volume based on local porosity variations. To enhance numerical stability, we introduce a modified dynamic particle collision regularization technique and employ an artificial density diffusive term that accounts for variable-volume particle interactions. We validate the developed SPH-porous media formulation against theoretical predictions and experimental benchmarks, demonstrating its capability to capture long-term wave propagation over permeable structures. Results confirm that our SPH model effectively handles particle interactions with varying volumes at the porous medium interface, mitigating particle clustering issues. This work provides a robust and high-performance SPH tool for investigating wave dynamics in coastal engineering applications, including the design of permeable breakwaters and revetments.