Sonic Under-Expanded Co-Flowing Jet Mixing Characteristics with Varying Lip Thickness.

This article presents the jet mixing characteristics of sonic under expanded co-flowing jet by means of varying the lip thickness between the primary and secondary nozzle. The lip thicknesses between the nozzles chosen were 0.3Dp and 1.5Dp and their jet mixing characteristics is studied numerically for the nozzle pressure ratio of 5. The jet mixing effectiveness in the axial and radial directions were analysed by the total pressure decay plots and contours of Mach number, density gradient and turbulent kinetic energy. The results exhibit that, for the reduced lip thickness of 0.3Dp, the core of the primary jet is increased due to the encasing given by the surrounding jet. For the dominant lip thickness of 1.5Dp, the primary jet core is reduced due to the strong interaction between the primary and co-flowing jet. The various jet mixing phenomenon like shear layer between surrounding jet and atmosphere, recirculation zone and Mach disk were also analysed from the contour plots. [ABSTRACT FROM AUTHOR]