APPLICABILITY OF THE DUPUIT-FORCHHEIMER LAW IN REPRODUCING WAVE HEIGHT ATTENUATION EFFECTS BY MANGROVES

Abstract

 In order to develop a practical model of the attenuation effect of coastal vegetation, such as mangroves, on tsunamis and waves under various topographic conditions, researchers must focus on two key factors. Firstly, developing a three-dimensional model capable of handling breaking waves and turbulent currents is important. Secondly, it is essential to establish a modeling method that keeps computational costs low. Yoshida et al. (2022) showed that a mangrove forest could be modeled using the Dupuit-Forchheimer law (hereinafter referred to as the DF law) and that valid calculation results can be obtained even with a grid size about four times larger than the thickness of a mangrove tree trunk by appropriately setting the resistance coefficients. Therefore, this study aims to investigate the influence of the resistance coefficient and the grid resolution of the numerical model in applying the DF law on the accuracy of tsunami wave height attenuation reproduction for several experimental cases. As a result, the experiment could be reproduced regardless of the lattice resolution. The wave height attenuation effect by mangroves in the experiment was reproduced in the calculation using the DF law.