Predictions of the Laminarization Phenomena in an Axially Rotating Pipe Flow

Numerical predictions are compared with the experiments of swirling turbulent flows in a pipe where the swirl is driven by the pipe wall rotating around the pipe axis. The laminarization phenomena, that is, the deformation of the axial velocity profile into a shape similar to the laminar one and the decrease of the friction factor, caused by the pipe rotation can be predicted by the calculations applying the stress equation turbulence model. However, calculations applying two types of the k-ε two-equation models with and without the modification by the Richardson number, cannot predict the laminarization phenomena and the characteristic behaviors due to the swirl. The interpretations of the laminarization phenomena and the applicability of the turbulence models are presented.