Effect of Thermal Stratification in Meandering Turbulent Open-Channel Flow with Varying Sinuosity

Abstract

This study utilizes a detailed analysis of the first direct numerical simulation (DNS) of thermally stratified open-channel flows through idealized sine-generated meanders with varying sinuosity to enhance our understanding of the impact of thermal stratification on the mean flow, secondary currents, and boundary shear stresses. Four different channel sinuosities Si=(1.07,1.34,2.12,3.70) at a moderate curvature of Rmin/B=2.5 and channel aspect ratio B/H=10 with friction Reynolds number Reτ=200 in neutral and density stratified flows are presented. The results indicate that thermal stratification has a significant effect on the characteristics of the mean flow, resulting in differences in the separated shear layers and separation zones for different sinuosity, as well as in the bed and sidewall shear stress distributions for both neutral and stratified flows.