ABSTRACT

An experimental study of turbulent jet from a vertical slot diffuser is reported. The velocity measurements were performed using a high resolution particle image velocimetry (PIV) system. The Reynolds number based on the cross sectional area of the slot at the exit plane and the average velocity was Re_h = 4100. It was observed that the Coanda effect caused the jet to deflect towards the side wall closer to the slot; however, the half-widths determined on either side of the centerline of the jet are remarkably similar. The vena contracta effect produced by the sharp edged slot exit also caused the centerline velocity to increase by 47 percent of its value at the exit plane. The streamwise mean velocity profiles across the jet are symmetric with respect to its local maximum value while the Reynolds shear stress profiles show the expected anti-symmetric distribution in accordance with the orientation of the mean shear layer. Two-point correlations of the fluctuating velocities were employed to provide insight into the turbulence structure.