An Experimental Study on Scour at Zero Degree Confluent Channels

This paper presents an experimental study on scour depth at the confluence of a mobile and a rigid bed open channel. Substantial momentum difference between the confluent channels controls flow hydrodynamics and mixing in the confluence hydrodynamic zone. Scour at the confluence of the channels is a threat to the stability of the structure separating the two channels. Results for bed morphology and maximum scour depth at the confluence for different hydraulic and geometric conditions in the channels are presented. Data analysis shows that the discharge ratio (ratio of discharge in mobile bed and total discharge downstream) and tailwater conditions are key factors affecting the bed morphology and maximum scour depth. The maximum scour depth decreases by increasing the discharge ratio and tailwater depth.