Effect of Cross-Wire Location on the Mixing of Underexpanded Sonic Jets

This paper presents the results of an experimental investigation carried out to study the effectiveness of a passive control in the form of a cross-wire located at the nozzle exit and downstream of the nozzle exit for promoting jet mixing. The advantage of locating the cross-wire at downstream of the nozzle exit is to keep the flow at the nozzle exit undisturbed, to avoid thrust loss. Sonic jets at nozzle pressure ratios (NPR) of 3, 5, and 7 were investigated with cross-wire at the nozzle exit, at 1De and 2De from the nozzle exit. The cross-wire influenced the supersonic core, causing the significant reduction of core length and mixing enhancement. The cross-wire also results in diffusion of shocks for all the cross-wire locations and at all tested NPRs.