Author(s): Mitchell Baum

Linked Author(s): Mitchell Baum

Keywords: Marine outfall; Brine discharge; Inclined dense jets; Waves; Physical modelling;

Abstract: An experimental investigation into the behavior of inclined dense jets in the presence of regular surface waves is presented. Discharge dynamics from a single diffuser port are systematically considered under various wave scenarios, for counter-propagating wave-discharge regimes. High resolution, two-dimensional spatiotemporal measurements of discharge dynamics were obtained in a laboratory flume using a light attenuation system. The time-averaged data are presented in dimensionless form as a functions of the newly defined wave-Froude number, ( = horizontal wave-amplitude velocity to jet velocity ratio; = jet densimetric Froude number). Experimental results revealed distinct variations between discharge- and wave-governed regimes. Under low wave-induced velocities, the jet behavior was similar to a quiescent discharge regime however under large orbital wave-forcing conditions deflections over the ascending jet phase and spiral flow paths occurred, causing significant reductions in both the trajectory and dilution. For > ~0.5, trajectory properties are wave-governed, while reductions in dilution result for > ~1.0. The decay of both trajectory and dilution entities arise due to the complex interactions of cyclic deflection over the jet ascent phase, arrested flow development, re-entrainment and emergence of the self-Coanda effect. These outcomes have implications for the design and operation of desalination outfalls in coastal environments.

DOI: https://doi.org/10.3850/38WC092019-1175

Year: 2019