Abstract
In flood flows of curved rivers, a risk of the river bank and the bed erosion are increased. To avoid the risk, it is necessary to control the primary velocity. In this study, four types of zigzag roughness, which are upward step type, downward step type, vertical type and composite type, were focused. Characteristics of the velocity profiles of the curved channel flows with zigzag roughness were investigated using an electromagnetic velocity meter. The results indicate that individual velocity profiles are formed corresponding with zigzag roughness. The four types of zigzag roughness contribute to a low speed region near the side wall and secondary current. In particular, it is possible that composite type roughness can avoid a contact with high speed fluid to the water colliding front and the outer bank of the curved channel.
