Author(s): Mona Nemati Attar; Akbar Safarzadeh
Linked Author(s):
Keywords: Channel confluence; Flow structure; Numerical model; Width ratio; Pressure gradient. 1
Abstract: River channel confluences are critical interface where intense changes in physical processes occur. These changes affect both the local and downstream characteristic of the river flow and of the bed. In the present study, using SSIIM 2. 0 model first the turbulent flow pattern at two river confluence with 90 degrees confluence angle has been simulated and numerical results are compared with available experimental results. Then, in order to investigate effects of gradual changes of the main channel width on the water surface map and also on the characteristics of the separation zones, diverging and converging cases with various width rations have been simulated. Results illustrate that due to longitudinal pressure gradient which arises from channel width changes, increasing downstream width of the main channel as well as a decrease in discharge ratio leads to various changes in characteristics of the separation zone, higher velocity amplification, and also intensified water surface variations in the confluence zone.
Year: 2013