Abstract
Three kinds of flow visualization technique have been used to determine the average characteristics of coherent structure in narrow rectangular open channels. The results indicate that some aspects of streamwise vortices, respect to pattern of existence, behavior, and formation. The concentrated region of streamwise vortices is dominated by width-to-depth ratio, b/h, and wall roughness. A mechanism for the formation of low speed region of the flow field is explained by the motion of the streamwise vortices.
