Nozzle lip thickness effect on turbulent kinetic energy distribution in subsonic rectangular co-flow jets

Abstract The effects of nozzle lip thickness on turbulent kinetic energy characteristics of subsonic rectangular co-flowing jet decay of a Mach 0.6 primary jet have been studied numerically. Subsonic rectangular co-flowing jets from a rectangular co-flowing nozzle with lip thicknesses of 1 mm (Thin Lip), 5 mm (Mid Lip), and 10 mm (Thick Lip) have been studied. Jet centerline turbulent kinetic energy variation, radial turbulent kinetic energy distribution – along major axis ( y -direction) and along minor axis ( z -direction) were analyzed. The results show that the mixing of the thick lip rectangular co-flowing jet is superior to the mid and thin lip rectangular co-flowing jet. This is because the lip thickness of the thick lip rectangular co-flowing jet has a strong influence on the turbulence generation, shear-layer development, and overall mixing behavior of the coaxial jet. For thick lip jets, turbulent kinetic energy experiences a significantly higher peak in the near field than the thin lip jet, which experiences a significantly higher peak in the far field. For mid lips, the mixing becomes inferior to that of the thick lip jet and superior to that of the thin lip jet.