大きな流量を有する支川が直角合流する河道区間の三次元流れと河床変動の解析

抄録

In the 2011 flood, due to the large flood from the Ikarashi River, flow attacking zone and separation zone were formed at the confluence of the Shinano River and Ikarashi River, and large-scale bed scouring and sediment deposition occurred. Therefore, it is important to understand characteristics of the flood flows and bed variations around the river confluence and to establish the numerical model capable of estimating them.

In this paper, we develop the numerical model to estimate the three-dimensional flow and bed variation around the confluence of the Shinano River and Ikarashi River by using the general bottom velocity computation (BVC) method. The BVC model shows that the depth of the erosion and deposition in separation area are not sufficiently reproduced, but structures of unsteady three-dimensional flow and bed variations are described on the whole.