Passive Flow Control of a Rectangular Jet

Abstract

The present paper describes to suppress the spread of a rectangular jet by a passive flow control method, which is to use deflectors or tapered triangular tubes installed inside a rectangular nozzle, and serrated tabs installed at the exit of the nozzle. These additional devices can change the velocity distribution of air flow issuing from a rectangular nozzle. Regarding a rectangular jet with deflectors, the equivalent jet spread for the nozzle with divergent deflectors is the largest, and the convergent deflector is the least of the three jets. Regarding a rectangular jet with serrated tabs, the equivalent jet spread for the nozzle with tabs placed on the long side of the nozzle is the largest of the four jets. Also, tabs placed on the short side or both sides of the nozzle are smaller than those without tabs. The equivalent jet spread for the nozzle with divergent tubes is the smallest of the three jets. Therefore, the spread and the axis-switching location for the rectangular jet can be controlled by the deflectors, serrated tabs, and triangular taped tubes.