Resonance Phenomena in a Semi-Closed Basin with Two Regions of Wooden Fences

This study investigates wave resonance phenomena in a semi-closed rectangular basin equipped with two porous wooden fences. These fences act as partially permeable structures and are modeled by modifying linear shallow water equations (LSWE) to accommodate its roughness and porosity. An analytical formulation is developed and validated against the theoretical resonance period for a flat-bottom basin, showing excellent agreement with zero relative error. To complement the analytical approach, a numerical simulation is constructed using the finite-volume method on a staggered grid. The simulation successfully captures the resonance behavior under different basin configurations. The results reveal that resonance persists when the roughness coefficient of the fences is low ( C f = 0.1), but is significantly damped or entirely eliminated when C f ≥ 0.25 or when porosity is reduced. Increasing the width of the fences or placing them closer to the hard wall contribute to reducing wave elevation, although the effect of increased width is noticeably more significant. These findings highlight the influence of wooden fences on resonance phenomena and provide insight into the design of coastal structures for resonance mitigation.