NUMERICAL MODELING METHOD FOR MANGROVES USING THE DUPUIT-FORCHHEIMER LAW

Abstract

 The tsunami attenuation effect of coastal vegetation such as mangroves as green infrastructure is widely known through field surveys of disasters. However, a detailed analysis of the vegetation in the form of prop roots requires small grid resolution and enormous computational resources. Since this analysis is difficult to perform at current numerical processing speeds, it is necessary to establish a low-cost calculation method to be applied to wide-area calculations. In this study, mangroves were used as the target of coastal vegetation and were simply reproduced by porosity. The Dupuit-Forchheimer law, which is independent of the grid size, was used to verify the validity of the method by comparing it with physical experiments and to propose appropriate resistance coefficients through sensitivity analysis. As a result, under the incident wave conditions of this study, the wave height attenuation effect was reproduced with relative accuracy at both 1 cm and 2 cm grid resolutions when 𝛼₀=1000 and 𝛽₀=1.0.