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Title: Mechanics of flow from stratified reservoirs in the interest of water quality : hydraulic laboratory investigation
Authors: United States. Army. Corps of Engineers. Philadelphia District
United States. Army. Corps of Engineers. Savannah District
Bohan, Joseph P.
Grace, John L.
Keywords: Computer programs
Hydraulic models
Intake structures
Hydraulic structures
Stratified flow
Water quality
Fluid mechanics
Publisher: Hydraulics Laboratory (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Technical report (U.S. Army Engineer Waterways Experiment Station) ; H-69-10.
Description: Technical Report
Abstract: Investigations were conducted to determine the characteristics of the withdrawal zone resulting from the release of flow through an orifice from a randomly 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. Distributions of density, generated by differentials in both temperature and dissolved salt concentration, and velocity were observed at various locations within a 1-ft-wide channel upstream of 0 .08- and 0.16-ft-square orifices. These data were used to develop generalized expressions describing the limits of the zone of withdrawal and the distribution of velocities therein. In certain cases, the proximity of the free surface and/or bottom boundary may dictate the upper and/or lower limits of the zone of withdrawal. Means were developed (Appendix A) for evaluating the conditions under which these boundaries dictate the limits of the withdrawal zone and for determining the distribution of velocities within a zone of withdrawal restricted by boundary conditions. A sample problem (Appendix B) is presented to illustrate application of the results to determine the maximum discharge that may be released through a square orifice for a given set of conditions without exceeding the limits of a desired hypothetical zone of withdrawal. The example also illustrates how the actual limits of the zone of withdrawal and the velocity distribution therein are determined. A method is illustrated for predicting the dissolved oxygen content and/or other water quality parameters of the outflow provided the vertical distributions of these parameters in the reservoir are known. A FORTRAN IV program is presented in Appendix C. This program can be used to solve three different approaches to the selective withdrawal problem: (1.) determination of the allowable discharge for selected withdrawal limits and the orifice size and elevation; (2.) determination of the withdrawal zone characteristics for a selected discharge and orifice size and elevation; and (3.) determination of the allowable discharge and orifice elevation for selected withdrawal limits and orifice size. The density and/or temperature profile in the reservoir must be known or assumed for all three conditions. The effect of orifice shape on the withdrawal characteristics was tested and analyzed after the draft of this report was prepared. The results were believed to be pertinent and are discussed briefly in the Discussion section of this report.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Technical Report

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