Numerical Model for Sea Outfall Hydraulics

Abstract

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