Control of high-speed jets, with passive control in the form of tabs of various shapes has been reported by large number of researchers in open literature. A tab is essentially a small solid strip kept normal to the flow, usually at the nozzle exit. A tab (placed normal to the flow) generates a pair of counterrotating transverse vortices (with the axis of rotation along the tab length), which become streamwise soon after shedding, that can influence the jet flow development significantly. From the vortex theory, it is well known that, the smaller the vortex size the better is its mixing promotion efficiency. Also, small vortices are stable and can travel longer distances compared to large vortices, which are unstable. In the subsonic and sonic jet studies reported so far, tabs of straight edges only have been studied. To exploit the advantage of smaller vortices, rectangular tabs with corrugated edges have been studied in the present investigation. To understand the effectiveness of corrugated rectangular tabs, and their relative performance compared to identical plain rectangular tabs, jets from Mach 0.3 to Mach 1 axisymmetric convergent nozzle without control, controlled with corrugated tabs and plain tabs have been investigated in the present study.
Last date updated on July, 2014