Numerical study on the influence of mangrove density and belt width on wave attenuation characteristics under regular waves

Abstract

In this study, a three-dimensional numerical wave flume is established using the meshless Smoothed Particle Hydrodynamics (SPH) method based on DualSPHysics, to investigate the effects of mangrove plant density and belt width on wave attenuation under regular waves. Validation is performed by comparing the numerical results with the second-order Stokes wave theory and experimental data of wave run-up on a vertical cylinder. The model yields an absolute error of 0.05 m, a relative error of 3.125%, and a root-mean-square error of 0.08 for wave crests and troughs, indicating that the accuracy meets the research requirements. Mangroves are simplified as rigid cylinders, and numerical simulations are conducted for regularly arranged cases with plant density ranging from 0.017 to 0.126 and belt width from 0.05 to 0.802. The results demonstrate that mangroves can significantly attenuate waves, and the wave dissipation effect is enhanced with increasing density and belt width. The wave height attenuation rate increases approximately linearly with density: it rises by about 6.25% when the density increases from 0.017 to 0.0314, and by approximately 12.5% when the belt width increases from 0.05 to 0.2335. Mangroves only dissipate wave height and energy without altering the wave period.