CHEN Wenchuang, ZHANG Rui, ZHANG Wenyuan, ZHANG Jinxiong, ZHANG Dong
This study analyzes the effects of various turbulence models on the hydrodynamic simulation accuracy and computing time for flow in a complex asymmetric penstock. The turbulence models used here for closure of the Reynolds-averaged Navier-Stokes (RANS) equations were the shear-stress-transport k-ω (SST k-ω), standard k-ε (Sk-ε), realizable k-ε (Rk-ε), renormalization group k-ε (RNG k-ε) and Reynolds stress model (RSM) models. The results show the differences in the velocity, turbulent kinetic energy, and water head loss predictions and the computing times for these five turbulence models. The predictions are compared with experimental data to show that the computing times and the differences between the numerical and experimental results vary with the flow conditions. The RSM results agree best with the experimental results, while the SST k-ω model costs less CPU time. Both the RSM and SST k-ω are found to be appropriate for calculating the hydraulic characteristics of the flow in the complex asymmetric penstock, depending on the available computing resources and the required accuracy. The Sk-ε, Rk-ε and RNG k-ε models all give lower accuracy predictions of the flow distribution, confluence and water head loss.
