Abstract
Riverside embayment is often connected with primary river flow through a conjunction channel. It is important to maintain water quality in such a dead water zone during ordinary water-stage. In this study, we concentrated on the effects of length and orientation angle of the conjunction channel on flow structures and water exchange rate. The flow patterns in embayment zones were extremely changed by the orientation angle of the conjunction channel. When the length of conjunction channel is long relatively to the width, an isolated vortex was generated in a conjunction zone. This vortex fluctuates and penetrates intermittently into embayment zone. This indirect inflow generates consequential vortices but the magnitude of these vortices are considerably smaller than those caused by direct inflow. The water exchange rate was generally proportional to the velocity scale but it was affected by the vortex structures.
