An experimental study of jets in cross-flow in a square duct

Abstract The flow field resulting from injecting a turbulent jet into a steady cross-flow confined in a square duct with relative small size has been studied using flow visualization by Schlieren imaging and Laser Doppler Velocimetry (LDV). The transparent duct is intended to simulate the flow field in the intake port of an internal combustion engine fueled by a gaseous mixture. Jets with three different jet-to-cross-flow momentum flux ratio R have been injected into the same cross-flow. The Schlieren images show that the relative small size of the duct would confine the development of transverse jets when R is higher than ≈ 2, and the interaction among jet, cross-flow and sidewalls strongly influences the mixing process between jet and cross-flow. The wellknown flow feature formed by a counter rotating vortex pair (CVP) has been observed through LDV measurement, for all the investigated R, and found to persist far downstream the jet exit section.