Effect of slanted perforation in tabs for subsonic and transonic jets

Abstract

Jet from convergent nozzle under correctly expanded condition was controlled by two tabs kept opposite to each other with straight perforation and slanted perforation at different angles of 10°, 20° and 30°. This jet was compared with uncontrolled jet and jet with solid tab. It was found that jet with tab of slanted perforation 30° was having a lesser potential core as compared to jet with solid Tab. Further it was found that the effectiveness of the tab with slanted perforation increased with increasing slanted perforation angle. The streamwise vortices introduced by the slanted perforation in tabs were inclined towards the centreline of the jet and thereby causing the disturbance in potential core region of the primary jet and resulting in faster decay of the jet.