The effect of density ratio on the mean spread rate of a low pressure drop oscillating jet nozzle

Abstract

Particle Image Velocimetry measurements were obtained in the highly unsteady turbulent flow issuing from a triangular oscillating jet (TOJ) nozzle into a fluid of different density. The TOJ nozzle comprises a triangular jet partially confined within an axi-symmetric chamber that produces a large-scale flow oscillation which is analogous to that in a precessing jet nozzle previously investigated. The initial spreading angle of the emerging jet was found to depend upon the density ratio, but in a more complex and different way to that of an unconfined jet. Instead, an increase in the density ratio of the jet fluid to the surroundings is found to be analogous to a decrease in the ratio of the nozzle length to diameter.