Computational Study of Slotted Tabs for Controlling Subsonic Jet Flow

The success of using rectangular slotted tabs with three distinct slot profiles - slant, L-bent and arc, to numerically control the Mach 0.6 jet is discussed in this paper. In the outflow plane of a 13 mm diameter convergent nozzle, a perforation, slot, or aperture is made on the adjacent faces of two rectangular tabs spaced 180 degrees apart. For a flow blockage ratio of about 7.3%, the tabbed jet's jet spread and flow development properties are examined. Due to significant levels of turbulence caused by the flow from the slots interacting and impinging into the mainstream flow perpendicularly, it is discovered that the slots encourage mixing. Comparing this behaviour to the free jet also results in jet instability. It is discovered that slotted tabs perform better as mixing promoters than free jet. For the tabs with slanted, L- bent and arc slotted surfaces, a reduction in potential core length of approximately 78.5, 85.71 and 87.5 %, respectively, is obtained in comparison to the free jet.