Investigation on the width-to-depth ratio effect on turbulent flows in a sharp meandering channel with periodic boundaries using Large Eddy Simulations

Abstract

Abstract As one of the most common river patterns in nature, meandering river has very complex flow structures in its curved channel bends, including secondary flow structure and primary flow velocity redistributions. To date, most of the studies have been carried out on the complex flow structures of a single channel bend with unavoidable influence, while the turbulent flow structures in periodic sharp meandering channels require further investigations. In this paper, Large Eddy Simulations (LES) are employed to reveal the flow structures of periodic sharp sine-generated bends with different width-to-depth ratios and dimensionless curvature radiuses. The results highlight the determining effects of width-to-depth ratio on recirculation zone’s size, the recirculation zone’s size is generally larger in Sine-Generated-Curve (SGC) Channel with large width-to-depth ratio, its size reaches maximum between the zero-curvature section and the apex section. The IBC (Inner bank cell) only forms in a small-sinuosity SGC channel with a small width-to-depth ratio, for SGC channel with large width-to-depth ratio, only one circulation cell is observed near the inner bank. The turbulent kinetic energy (TKE) is mainly influenced by width-to-depth ratio and dimensionless curvature radius.