The influence of the installation position of serrated tabs on the flow characteristics of a 2:1 rectangular jet

Abstract

The effect of the installation position of serrated tabs on the flow characteristics of a rectangular jet was studied experimentally. The serrated tabs, i.e. flat tabs of delta configuration, were placed on the short, long or both sides of a 2:1 rectangular nozzle. Measurements of mean and fluctuating velocities were made with cross– and single–wire probes for Reynolds number based on the height of nozzle of 9,000. In the case of the rectangular jet with tabs placed on the short sides, the y–axis spread of jet increases more than the z–axis spread of jet, and the intersection point of axis–switching get closer to the nozzle exit than the jet without tabs. On the other hand, in the case of the rectangular jet with tabs placed on the long sides, the y–axis spread of jet decreases less than the z–axis spread of jet, and the intersection point of axis–switching moves farther from the nozzle exit than the jet without tabs. Moreover, in the case of the rectangular jet with tabs in both sides, the intersection point of axis–switching moves between that of jet with tabs placed on both short and tabs placed long sides. Therefore, the installation position of serrated tabs at a 2:1rectangular nozzle exit significantly affects the development of rectangular jet.

Keywords

• rectangular jet
• serrated tabs
• flow control
• flow measurement
• flow visualization
• axis–switching
• jet spreads