Measurements in the flowfield of an interrupted turbulent free jet

Abstract

The near flowfield of an interrupted turbulent free jet, which consists of four unventilated rectangular jets, has been studied experimentally. The quantities measured, using hot-wire anemometry, include: the three components of the mean velocity vector and the Reynolds normal and primary shearing stresses. The results show that, compared to a single, uninterrupted, rectangular jet of aspect ratio 10, the mixing in an interrupted jet is enhanced. The enhanced mixing is evidenced by a faster decay of the mean streamwise velocity along the jet centerline and higher centerline streamwise turbulence intensities. The results also show that the unventilated multiple turbulent rectangular free jets of the present study develop faster into a single jet, implying complete mixing, than their known ventilated counterparts. The measured Reynolds normal and primary shearing stresses are higher than those found at corresponding locations in a round turbulent free jet and are thus consistent with the faster mixing of the interrupted turbulent free jet.