Inclined negatively buoyant jets 2: concentration measurements

Abstract

Experiments on concentration measurements in round turbulent negatively buoyant jets discharging into a calm homogeneous fluid at three different angles are presented. Detailed measurements using a micro-scale conductivity probe were carried out at the horizontal location of the terminal rise height, mostly along the vertical of the axial jet plane and in the transverse direction. The dimensionless vertical distribution of the mean concentration is found to be asymmetric, whereas the transverse distribution is approximately Gaussian. At the same horizontal location, the vertical distribution of the concentration turbulent intensity has a maximum at a point systematically higher than the jet axis. The width of the mean concentration distribution, the heights to the location of the maximum mean concentration and to the maximum turbulent intensity as well as the minimum dilution are determined. From measurements in the region where the jet returns to the source elevation, the minimum dilution and the horizontal distance to the return point are estimated.

Keywords:

• Concentration
• desalination brine
• dilution
• inclined turbulent jet
• negative buoyancy
• turbulent intensity

Acknowledgements

Research leading to this work was conducted in the course of the Doctoral Thesis of the first Author at the National Technical University of Athens (NTUA). His financial support through a grant of the Research Committee of NTUA is acknowledged. The contribution of Mr Manolis Lasithiotakis, Technician of the Applied Hydraulics Laboratory, to the construction of the experimental apparatus is also acknowledged.

Additional information

Notes on contributors

Ilias G. Papakonstantis

Current address: 10 Thasou Street, 15125 Marousi, Athens, Greece. [email protected]