Numerical Investigation on Turbulent Characteristics of downstream of the U-bend Open Channel for Different Froude Numbers

The turbulent fluctuation intensity, during to the effect of the bend, enhances in downstream of the bend, however, most of the experimental and numerical analyzes are investigated on the flow phenomena in a bend and only limited articles have focused on the flow properties in the downstream of the bend. Combined with the volume of fluid (VOF) method, renormalization group (RNG) k-ε turbulence model was employed to numerically investigate the turbulent properties in the downstream of the U-bend open channel with various Froude numbers (Fr). A comparison was carried out between the numerical simulation and experiment, and then detailed investigations have been performed from the turbulent kinetic energy (TKE) and turbulent dissipation rate (ε) with varying Froude numbers to investigate the turbulent characteristics. The calculated results suggested that TKE and ε were conspicuously influenced by Fr. The average turbulent kinetic energy (TKE-A) and turbulent dissipation rate (ε-A) decreased along the downstream of the bend. The intensity of the TKE and ε increased with the increasing Froude numbers, however, the rate of variation with the TKE-A and ε-A declined as the Froude number increased.