振幅の大きな蛇行河道と下流直線河道の接続部における流況と河床形態に関する基礎的研究

Abstract

Laboratory experiments were performed on fundamental characteristics of flow pattern and bed topography in the connection area between an upstream large-amplitude meandering channel and a downstream straight channel. It is found that, in the fixed-bed condition, the water depth in the meandering channel drops down locally just in front of the connection point, which is lower than the water depth in the straight channel, and that, as well as along the meandering channel, the lateral location of the maximum main flow velocity swings from side to side along the straight channel to a certain extent downstream from the connection point. It was also observed that, in the movable-bed condition, sandbars are formed in the extent region in the straight channel due to such flow characteristics.