Computational Study of the Effect of Slot Orientation on Synthetic Jet-Based Separation Control

Abstract

A computational study is conducted to explore the effect of synthetic jet orientation on boundary layer separation control. A six-to-one aspect-ratio rectangular slot is chosen in the current study and streamwise and spanwise orientations of this slot are analyzed. In the first part of this study, the interaction of the jet with an attached laminar boundary layer for both slot configurations is examined. The dominant feature in the streamwise oriented slot is a pair of strong counter-rotating streamwise vortices and these are missing in the spanwise oriented slot configuration. These streamwise vortices undergo stretching and tilting to form a series of hairpin vortex structures and analysis shows that sweeping motions associated with these vortices bring high momentum fluid into the boundary layer. A variety of flow statistics are computed and these indicate that despite the smaller overall blockage represented by the streamwise oriented slot, it is more effective in increasing the momentum of the boun...