HYDRODYNAMICS OF RIGHT-ANGLED CHANNEL CONFLUENCES BY A 2D NUMERICAL MODEL

10.22099/ijstc.2013.1617

Abstract

Hydrodynamics of open channel confluences is very complicated. Simulation of rightangled
channel confluences using a recently-developed 2D high-resolution model is presented in
this paper. Finite-volume discretization of governing equations is adopted and fourth-order Runge-
Kutta time integration is used. The effects of three different and most influential parameters,
including discharge ratio, width ratio and downstream Froude number on hydrodynamics of rightangled
confluences are studied. Standard Cartesian grids are employed and a single-block strategy
is used for modeling the confluence. Turbulence shear stresses are included within the numerical
model based on an eddy-viscosity approach. The results are compared with experimental data and
show satisfactory agreement, particularly in cases when 3D features of flow are negligible. Despite
having 3D characteristics in most cases, the results of this study show that a much simpler and
computationally effective 2D numerical model is also capable of detecting most important features
of flow in confluences, including separation zone and zone of high-velocity.

Keywords