An Experimental Study on Structure of Jet Injected into Crossflow

Ni-oh Puzu; Suteera Prasertsan; Makatar Wae-hayee; Chayut Nuntadusit

Authors

Ni-oh Puzu Department of Mechanical Engineering, Faculty of Engineering, Prince of Songkhla University, Songkhla, Thailand
Suteera Prasertsan Department of Mechanical Engineering, Faculty of Engineering, Prince of Songkhla University, Songkhla, Thailand
Makatar Wae-hayee Department of Mechanical Engineering, Faculty of Engineering, Prince of Songkhla University, Songkhla, Thailand
Chayut Nuntadusit Department of Mechanical Engineering, Faculty of Engineering, Prince of Songkhla University, Songkhla, Thailand

Keywords:

JICF, CRVP, vortex generating jet, mixing jet

Abstract

Flow characteristics of a circular jet which was injected normal into the crossflow on flat plate, has been investigated by temperature measurement and flow visualization. The effect of jet-crossflow momentum flux ratio on jet flow behavior was studied by fixing the crossflow velocity and changing the velocity of jet flow. The experimental study was divided in two parts. First part, the flow visualization was done in water tunnel using Laser Induced Fluorescence (LIF) technique. Second part, the temperature of air jet flow was quantitatively measured with thermocouples and visualized the jet flow trajectory with smoke technique. The jet flow after injecting into crossflow had dome-shape structure and attached to the downstream surface for case of jet-crossflow momentum flux ratio less than 0.25. The results showed that the dome-shape structure was observed at the near field, while the Counter Rotating Vortex Pairs, CRVP appeared after that. When the jet was deep penetrated into the crossflow and moved away from the surface, which indicated jet-crossflow momentum flux ratio higher than 1.0, the jet flow had kidney-shape cross section and CRVP suddenly occurred in jet cross section behind the jet exit.