Maximizing the Efficiency of TPMS-Based Porous Floating Breakwaters: A Small-Scale Experimental Study on Wave Attenuation

Coastal regions are increasingly vulnerable to erosion, flooding, and habitat loss due to climate change-driven sea-level rise, intensified storm surges, and amplified wave energy, necessitating the development of innovative, sustainable coastal protection strategies. While traditional methods remain effective, they are often saddled with environmental drawbacks and high maintenance costs. The floating breakwater concept is a well-established coastal protection measure, offering adaptability to varying water depths and minimal ecological impact; however, optimizing its efficiency - particularly through advanced porous designs - remains an active research challenge. This study explores integrating triply periodic minimal surface (TPMS) geometries into breakwaters design to enhance and optimize their hydrodynamic performance and promote innovative coastal protection measures. Twelve three-dimensional-printed models with varying TPMS architectures, relative densities, and cell sizes (uniform and graded) were experimentally tested in a small-scale flume under 54 wave-current scenarios, analyzing wave reflection, transmission, and dissipation coefficients for their performance assessment. Unlike many previous studies that focused solely on waves, this research incorporates wave-current interactions to better simulate coastal environments. The results showed that diamond TPMS outperformed other geometries due to higher tortuosity and surface complexity, showing lower energy reflection and transmission and greater dissipation. Models with lower relative density and larger cell sizes (required up to 46% less material for printing) exhibited improved energy reflection performance. Additionally, cell grading proved effective in enhancing dissipation and minimizing wave transmission. The findings demonstrate the potential of TPMS-based floating porous breakwaters as a cost-effective, adaptable, and high-performance solution for future coastal protection systems.