Optimizing coastal forest arrangements for tsunami flow dynamics using a three-dimensional approach.

This article investigates the effects of five coastal vegetation configurations—tall vegetation (TV), short vegetation (SV), mixed vegetation (MV), short-then-tall vegetation (STV), and tall-then-short vegetation (TSV)—on tsunami flow dynamics using a three-dimensional computational fluid dynamics (CFD) model validated by physical experiments. The study finds that the TSV arrangement, where tall vegetation is positioned upstream followed by short vegetation downstream, most effectively dissipates energy, reduces downstream flood depths, and lowers fluid forces by up to 15%, thereby minimizing erosion risks and enhancing coastal protection. While TV alone provides strong energy dissipation and flow resistance, it increases near-bed velocities that may cause erosion, and SV and STV configurations offer limited resistance and energy dissipation. The research highlights the importance of strategic vegetation layering and arrangement in optimizing coastal forest design for tsunami mitigation, noting practical challenges such as vegetation growth conditions and environmental constraints that may affect real-world implementation.