Abstract
It is expected that coastal forest reduce tsunami height and velocity and mitigate its acting force on a structure behind the forest, but the characteristic of reducing effect depending on tsunami form, e.g. wavelength and steepness, is not revealed. In this study, hydraulic experiments were conducted to examine the effect of coastal forest, which was modeled with simple cylinders, concerning the passing inundation tsunami and its force acting on the structure behind. And 3D-numerical simulation, which becomes practical to estimate tsunami force by improving computing devices, was applied to reproduce the experimental results to discuss its applicability.
As a result, it was confirmed that the reducing effect on inundation height is remarkable during early phase of run-up tsunami because of the large velocity, and the effect was small in a case of long period tsunami because the velocity when the maximum inundation height occurs is small. In addition, numerical simulation accurately reproduced the reducing effect by coastal forest and its availability was confirmed.
