2007 Volume 13 Pages 237-242
Since a rubble mound groin has a permeable structure, through-flow water can be purified, pores and concaves of the mound provide living space for aquatic lives, and landscape around the structure is nicer and natural than those of artificial modern structures. In this study, focusing our attention on a set of rubble mound groins, a field observation and a numerical analysis were carried out in Akashi River in Hyogo, Japan, where the groins was partially damaged by a flood flow in 2004. A two-dimensional flow model was developed in order to reproduce flow fields during the flood and to estimate flow force acting on the structure. Hydrodynamics inside and outside the structure was discussed based on the numerical analysis. Characteristics of the flow such as streamline concentration and diversion around the structure, shear stress on the river bed and profiles of drag force acting on the structure were investigated.