Mechanics of Stratified Flow through Orifices

Investigations were conducted to determine the characteristics of the withdrawal zone resulting from the release of flow through a submerged orifice from a randomly density-stratified reservoir in experimental facilities for the purpose of developing means of predicting the quality of water discharged through similar openings in prototype intake structures. Density stratification, caused mainly by temperature differentials in the prototype, were simulated in the model by using salt and fresh water. Density and velocity distributions were observed at various locations within a 1-ft-wide channel upstream of an orifice. These data were used to develop generalized expressions describing the limits of the zone of withdrawal and the distribution of velocities therein. With the velocity distribution known, the weighted average technique may be applied to predict the temperature, dissolved oxygen content, and any other water quality parameter of the outflow for which a profile in the reservoir is known.