Turbulence models in pulsating flows

The performances of four low-Reynolds-number models are compared for the unsteady Reynolds-averaged Navier-Stokes equations applied to the How in a channel driven by a pressure gradient oscillating around a nonzero mean. The models considered are the one-equation Spalart-Allmaras model, the k-epsilon model with the wall functions of Lam and Bremhorst, the k-omega(2) model of Saffman and Wilcox, and the k-epsilon-v(2) model of Durbin. The results are compared with experiments, direct simulations, and large-eddy simulations. The models give similar and reasonably accurate results as far as predicting the velocity profile in the channel as a function of the phase and reproduce the observed behavior during part of the cycle. However, large differences exist between the models themselves, as well as with respect to the large eddy simulations, at the level of the Reynolds shear stress, turbulent kinetic energy, and dissipation rate. The k-epsilon-v(2) model is overall superior to the other models considered.