NUMERICAL-MODEL FOR SEA OUTFALL HYDRAULICS

A one-dimensional numerical model describing the internal hydraulics o f tunneled sea outfalls is reported. It includes some local two-dimens ional techniques to take the effects of buoyancy and stratified flow i nto account based on an understanding of purging and intrusion phenome na. The model was verified with data collected from laboratory experim ents. Effects of varying configuration, geometry, and hydrograph have been investigated in the model. It is concluded that head loss at rise r ports, tunnel angle of inclination, and change in elevation of riser tops have significant effects on purging and intrusion characteristic s. Any factor causing uneven velocity distribution among risers makes the system much more prone to intrusion. The operation hydrograph is a n important factor affecting purging behavior.