MEASUREMENT OF THE TURBULENT-FLOW FIELD IN A FREE-SURFACE JET OF WATER

Measurements of the mean velocity and turbulence intensity are present ed for a rectangular jet of water ejecting into a gaseous ambient. Dat a are reported for streamwise locations up to 30 nozzle widths from th e discharge and spanwise locations covering the inner 80% of the jet w idth. The flow conditions at the nozzle discharge were controlled by u sing different nozzle designs (parallel-plate and converging) and flow manipulators (wire grid and screens). The results track the mean velo city and turbulence intensity profiles with streamwise distance, highl ighting changes in both the profile shapes and magnitudes for both mea sured quantities. Independent of nozzle configuration, the mean veloci ty profile was shown to be most nonuniform and the turbulence intensit y most nonhomogeneous at the nozzle discharge. With increasing streamw ise distance, the mean velocity profile underwent a gradual transition to a completely uniform condition, while the turbulence field decayed and became homogeneous. The rate of viscous dissipation was shown to depend strongly on the nozzle exit condition.