Control of subsonic jets using vanes as vortex generators

Abstract

The passive control of jets using vanes as vortex generators is studied by numerical simulation in this paper. The vanes are positioned inside the nozzle near the exit, inclined to the flow with the longitudinal direction of the jet. Two configurations namely, straight vanes (k = 0 mm−1) and curved vanes (k = 0.05 mm−1) are considered. Curvature k is defined as the reciprocal of the radius of the vanes. The blockage due to the presence of the vanes is 0.5%. The total pressure variation along the jet centreline and along the radial distance is determined from nozzle exit at a Mach number of 0.4, 0.6 and 0.8. It is found that the vanes cause faster decay of the jet, both in the near field and far field compared to the base nozzle (plain circular nozzle) and the curved vanes perform better than the straight vanes in promoting the jet mixing. A maximum of 54% reduction in jet potential core length is achieved by the curved vanes and the jet becomes asymmetrical due to the presence of the vanes inside the nozzle, as observed in the radial pressure decay plots and Mach number contours.

Investigation of slanted perforation diameter in tabs for supersonic jet control

“…An active control method includes pulsed jets (Knowles and Saddington, 2005), micro jets (Khan and Rathakrishnan, 2004) and synthetic jets (Zaman and Milanovic, 2003). Passive technology includes tabs (Gandhinathan and Subramanian, 2022; Suseela et al , 2022) and chevron nozzle (Subramanian et al , 2018). The vortex generated by the active control techniques generates vortices that will not travel longer distances downstream of the jets.…”