NUMERICAL INVESTIGATION OF WAVE ATTENUATION BY COASTAL VEGETATION USING A FULLY-NONLINEAR BOUSSINESQ MODEL

Author

Felipe Espinoza Barraza, University of Rhode IslandFollow

Date of Award

2025

Degree Type

Thesis

Degree Name

Master of Science in Ocean Engineering

Department

Ocean Engineering

First Advisor

Che-Wei Chang

Abstract

Coastal vegetation, such as mangroves, plays an important role in dissipating wave energy, reducing shoreline erosion, and mitigating coastal flooding risks. However, accurately modeling wave attenuation by coastal vegetation remains challenging due to the complex hydrodynamic interactions involved.

This thesis addresses this challenge by evaluating the performance of a fully nonlinear Boussinesq model using laboratory measurements of wave attenuation through realistic mangrove structures. Experiments were conducted in 2023 at the Ujigawa Laboratory of Kyoto University using high-fidelity, 3D-printed Rhizophora stylosa models. The dataset, provided by Dr. Che-Wei Chang, includes synchronized measurements of free surface elevation, fluid velocity, and vegetation-induced hydrodynamic forces acting on mangrove models under regular wave conditions, providing a detailed basis for model validation. A two-dimensional configuration of the Boussinesq model FUNWAVE-TVD was used to simulate wave-vegetation interactions. Empirical drag (C_D) and inertia (C_M) coefficients were directly derived from the experimental data and integrated into the model. Simulated free surface elevations were compared with experimental measurements to assess model performance.

Results show that the model captures key trends in vegetation-induced wave attenuation, including increased energy loss with higher wave heights and longer periods. The analysis revealed that the dominant resistance mechanism (drag or inertia) varies with wave conditions, and that the relationship between wave steepness and hydrodynamic coefficients is not uniform across regimes. While overall agreement was reasonable, the model tended to slightly underestimate attenuation, likely due to the underestimation of C_D and spatial limitations in force measurements. These findings provide insight into wave-vegetation interactions and suggest that FUNWAVE-TVD can be a useful modeling tool for simulating nature-based coastal protection strategies involving vegetated systems.

Recommended Citation

Espinoza Barraza, Felipe, "NUMERICAL INVESTIGATION OF WAVE ATTENUATION BY COASTAL VEGETATION USING A FULLY-NONLINEAR BOUSSINESQ MODEL" (2025). Open Access Master's Theses. Paper 2651.
https://digitalcommons.uri.edu/theses/2651