抄録
The Yoshino River cohesive soil sample experiment showed two types of eroded bank; near-watersurface and under-water-surface. Flow field of the near-water-surface eroded bank was examined through physical bank model experiment and numerical analysis. In this paper, the flow fields near and inside of the both eroded banks are investigated. It shows that flow properties of the near-water-surface and underwater-surface eroded bank shapes are different, which signifies two different erosion mechanisms of the bank shapes. The numerical model, which was used to simulate near-water-surface eroded bank flow fields, could not reproduce the flow field of under-water-surface eroded bank because of its confined flow inside the eroded bank. A 2-D numerical model is developed incorporating SIMPLE method for the under-water-surface eroded bank. This model could reproduce the flow fields of successive model eroded banks of near-water-surface and under-water-surface for two different erosion stages.
