Title: AN EXPERIMENTAL STUDY ON THE FLOW IN COMPOUND SINUOUS CHANNELS
Abstract: A new series of experiments was conducted to study the flow structure in a compound sinuous channel. The experimental channel modelled the most typical Japanese compound river, and whose crossover angle was 30° and sinuosity s was 1.11. Flow visualisation both on the water surface and in the water body was carried out as well as velocity and depth fluctuations were measured.The results show similar internal structure of the flow to that in meandering channels in overbank conditions. A helicoidal motion of the flow is directly reflected to the fluctuation of the water surface. Auto-correlation factors calculated from the fluctuation clearly shows the periodic motion of the flow and its depth dependency. This periodic motion is mainly brought by that of the secondary flow induced and developed through the crossover region.