Abstract
A number of researches had been conducted about the flow structures in curved open channels, but they were limited to the channel with large width-to-depth ratio. This study aims to clarify the flow structure in curved rectangular open channels with small width-to-depth ratio, experimentally. The effects of the circumference angle and the radius of curvature of the curved channel were investigated. The obtained structures of secondary flow supported the conventional knowledge, but the existence of the counterrotating vortex near the outer bank was indicated. The developing process of the secondary flow was examined quantitatively with respect to the circumference angle and the radius of curvature. The structure of the primary mean velocity, the bed shear stress and the momentum transport were explained in relation to the secondary flow.
