Hydrodynamic performance of riprap structures in reef lagoon under extreme wave loading: Insights from porous media simulations

In this study, the numerical modeling of wave propagation and breaking in coral reef topography is established based on the Navier–Stokes equations. Based on the numerical simulation, the influence of the location, height, and permeability of the riprap structure on the wave attenuation characteristics was investigated. The results show that the riprap structure significantly reduces the wave height in the lagoon area by inducing wave breaking in advance. The reflection effect increases with the height of the riprap structure, but it may cause the water level in front of the reef to rise. The permeable riprap structure showed better wave dissipation performance at low tide and small wave heights, but the protection against solitary waves was weaker than that of impermeable riprap. The study provides a theoretical basis for the optimization of protective facilities for coral reefs and lagoons under extreme wave conditions.