Author(s): Sandor Baranya; Janos Jozsa
Linked Author(s): Sándor Baranya
Keywords: River confluence; 3D turbulence model; SSIIM; Scale model
Abstract: The paper presents a hydrodynamic investigation of the junction of two rivers in northwest Hungary in an urban area. The goal of the investigation was to study the complexity of the flow in such conditions by means of CFD and hydraulic scale model. The project gave the opportunity to compare the results of the distorted scale model with the ones of the CFD model in field scale, in the distorted hydraulic model scale, and also in undistorted scale. For comparison, the results were converted to field scale by assuming Froude similarity law. The effect of distortion and the robustness of the k-ε turbulence model in such complex confluence conditions were analysed. Agreement between observed and numerically modelled features was reasonable in smooth topography conditions upstream of the junction, whereas straight downstream of the junction significant differences between laboratory and numerical results were detected. The complex swirling and shearing character of the flow interacting with anisotropic local turbulence was found as a possible reason for that, which could be cured by a differential Reynolds-stress turbulence closure. The dependence of the shallow wake formation on the distortion rate and its proper choice in terms of the stability parameter was also underlined.
Year: 2007