Ocean Outfalls. III: Effect of Diffuser Design on Submerged Wastefield

The effects of port spacing and jet momentum flux on the characteristics of submerged wastefields produced by multi‐port ocean outfalls in linearly stratified currents were investigated experimentally. Within the parameter range studied the primary effect of these variables is on the rise height and thickness of the wastefield, and dilution is closely approximated by line plume results. Increased momentum flux causes a reduction in rise height at low current speeds while leaving the total entrainment path length of the jets, and hence dilution, fairly constant. The effects of increased momentum flux decrease as the current speed increases. Increased port spacing still resulted in merging of individual plumes even when fairly widely spaced, particularly in flowing currents, so point plume results were of limited applicability in predicting wastefield properties. Results are presented in graphical and tabular form from which rise heights and thicknesses can be estimated for discharges which do not approxima...