Mean flow characteristics, vertical structures and bed shear stress at open channel bifurcation

Abstract

Water supply from rivers is accomplished with flow diversion through an intake structure. A lateral intake like bifurcation is the simplest method to withdraw water. However, flow at a channel bifurcation is turbulent, highly three-dimensional (3D) and so has many complex features. This paper reports a 3D numerical investigation of these features in an open channel flow. Simulations have been done on rectangular channel geometry, with smooth bed and sidewalls. The standard k-ɛ, k-ω model of the Wilcox, and RSM turbulence models are compared using the commercial code FLUENT. The simulation results have been compared with available experimental data. It was found that all of the turbulence models tested here accurately predicted velocity profiles in the main channel but in the branch channel, the RSM model with the k-ω model performing better than the k-ɛ model. Predicted flow physics are in close agreement with previously reported experimental results.

Keywords

• Dividing flow
• CFD
• Secondary flow
• Turbulence model
• Sediment Transport