Numerical Prediction of Closed Contra-Rotating Disc Flows

Abstract

This paper provides the finite-difference solutions for closed contra-rotating discs flows at different disc speed ratios for a fixed value of rotational Reynolds number of order five. The flow structure reveals that when two discs rotate in opposite directions, the fluid mass outside the boundary layers is divided between two regions, which give rise to the formation of two-cell flow structure. In order to assess the different level of closures, two turbulence models low Reynolds number k-? model and low Reynolds number second moment closure have been employed to predict the essential features of the closed contra-rotating disc system. The most significant differences between the predictions of the two turbulence models occur at the peak of slower disc boundary layer, because flow is more complex and turbulent on this side. The comparison of predicted velocity profiles of two turbulence models show that the low Reynolds number second moment closure produce a better agreement with measurements, particularly along the boundary layers and in the central core region.

Keywords

• Contra-Rotating Disc Flows
• Low Reynolds Number Second Moment Closure.