Analysis of roughness density and flow submergence effects on turbulence flow characteristics in open channels using a large eddy simulation

In this study, a large eddy simulation of a turbulent channel flow with rib elements on a bed was performed using an extended version of the Werner-Wengle wall model to analyze the effects of roughness density and flow submergence on the flow features at depth, and to validate the applied model. The profiles of the mean velocity, turbulence intensity, turbulent kinetic energy, and turbulent production were compared with related experimental data. The mean and fluctuating velocity profiles demonstrated that the model could represent the turbulence structures and they showed that the combined effect of the roughness density and flow depth is important, especially at shallow depths with larger pitch-to-height ratios.