Effects of confinement and curvature on a jet in a supersonic cross-flow

Abstract

To reveal the effects of confinement and curvature on the jet mixing in a supersonic cross-flow, large eddy simulations were conducted to study the jet in supersonic cross-flow in a channel and a pipe at a Mach number of 2.7. The comparison was based on an equal friction Mach number, friction Reynolds number, and Prandtl number. The synthetic eddy model was utilized to generate the inflow turbulent boundary layer. Our study shows the major counter-rotating vortex pair (CVP) was higher in the pipe than in the channel, while the trailing CVP was larger and appeared within the recirculating flow. The pipe had a stronger shock train than the channel due to the confinement and curvature of the pipe. The jet penetration of the pipe is 18.4% larger than that of the channel at x/ D = 10, and the stream velocity of the pipe is much more reduced behind the jet than in the channel. Three reasons for the higher mixing efficiency of the pipe are revealed according to our findings, including the larger and higher major CVP, the higher penetration, the stronger shock. The mixing efficiency of the pipe is 4.68% higher than that of the channel due to the above reasons at x/ D = 10.