Numerical study of junction-angle effects on flow pattern in a river confluence located in a river bend

作者：Ghobadian Rasool^*; Tabar Zahra Seydi; Koochak Parisa

来源：WaterSA, 2016, 42(1): 43-51.

DOI：10.4314/wsa.v42i1.06

• flow pattern
• junction angle
• 180 degree bend
• SSIIM1 numerical model

The effect of main channel curvature on the flow pattern in river junctions is a complex and important issue. The 3-dimensional flow pattern in a river bend with a lateral or tributary channel is not only affected by the centrifugal force and pressure gradient but is also affected by the tributary channel's momentum. Understanding this phenomenon requires extensive research: in this study the effect of 4 tributary junction angles, placed at a 45 degrees angle from the beginning of the bend, is studied using SSIIM1 software. The effect of the junction angle on the vertical and transverse velocity profile, water level changes in the main channel, bed shear-stress distribution and secondary flow strength were evaluated. The results showed that by increasing the junction angle from 30 degrees to 115 degrees the streamwise velocity in the vicinity of the centre line and the inner wall of the bend increases. Increasing the junction angle also increases the separation zone dimensions, maximum bed shear stress, difference between the upstream and downstream water level in the junction and the secondary flow strength.

• 出版日期2016-1