A new approach to modelling initial dilution of a buoyancy-dominated jet in moving water

Initial dilution is one of the most important measures in the design of ocean outfalls. Considerable efforts have been devoted in the past to modelling initial dilution of a buoyancy-dominated jet in moving water. This paper reviews available initial dilution models and presents a new modelling approach based on a length scale analysis combined with an additive entrainment hypothesis, and nonlinear regression modelling. The proposed approach is more systematic and more justifiable than existing methods for two reasons: (1) it uses an objective measure to evaluate the model and (2) it includes the effect of ambient current in the buoyancy-dominated near field (BDNF). Using available experimental data, a new, continuous, initial dilution model is proposed and compared with presently available models. The proposed model is presented in both deterministic and probabilistic form.