Abstract: On the basis of previous studies，a simple flume experiment on Yaojian reach in the middle Yangtze River was carried out，and the evolution rule of braided channel was studied under the condition with /without river side bar． The results indicated that the variation trend of the thalweg with side bar was the same as that without aide bar，except that the former bed elevation was slightly lower than the latter’s; as to the region of separated flow，the lowest points of the river sections would lean to the right bank when the flow of the case with river side bar leaned to the right bank． As to the region of bifurcated river reach and river outlet，the flow and the cross-section would lean to the left bank; river side bar played an important role in the evolution process of the river island，and the river island volume would be smaller than that with no side bar．

Key words: side bar, flume experimental, river island

摘要： 以窑监河段为依托进行概化水槽试验，对有和无边滩条件下，弯曲分汊河段河床演变规律进行研究。结果表 明:有边滩和无边滩条件下河道深泓线的变化规律相同，有边滩时河床平均高程比无边滩时略低;对于分流区，水 流较无边滩时偏向右岸，断面的最底点也相应偏向右岸;对于分汊区和汇流区，水流较无边滩时偏向左岸，江心洲 右沿冲刷幅度较无边滩时大，断面的整体形态也相应偏向左岸;边滩对江心洲的演变也产生影响，有边滩时的江心 洲体积比无边滩时要小。

关键词: 边滩, 水槽试验, 江心洲