Browsing by Author "Wood, Addison"
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Item Calumet Pumping Station Hydraulic Model Study(St. Anthony Falls Hydraulic Laboratory, 1977-05) Stefan, Heinz; Wood, AddisonA hydraulic model of the underground pump suction intake structure of the Calumet Pumping Station was built and tested. The pumping station is an element of the projected Chicago storm runoff collection and treatment system, to be completed within the next few years. The study was conduoted for DeLeuw, Cather and Co., Consulting Engineers and Planners, Chicago, Illinois, on behalf of the Metropolitan Sanitary District of Greater Chicago. The model was built at a scale of 1:14, mostly out of plexiglass to facilitate observation. The model included the downstream end of the Calumet Tunnel, a drop structure, two symmetrically placed ducts, a wet shaft and a suction header with three branch pipes as shown in Figs. 1 through 8. It was the objective of the hydraulic model study to identify and document (a) problems with flow separation, secondary currents and vortex formation by flow visualization, (b) air entrappment and air entrainment during filling and during pump operation, (c) piezometric heads and head losses throughout the structure, (d) accumulation and entrainment of fuel oil, resulting from accidental spills, throughout the structure (e) transport and deposition of grit throughout the structure. As a result of the initial observations made in the model, the structure was modified in two locations to improve flow characteristics and to reduce grit deposition. The observations made in the model with regard to flow patterns, air entrainment and fuel entrainment have been documented by still pictures (black and white) and color motion picture. Head losses are reported in tabular and graphical form. The performance of the structure (Design C in Fig. 10) with respect to air entrainment, fuel entrainment and head losses appears quite satisfactory. Grit deposition was largely reduced but not fully eliminated. The following specific findings and recommendations were made: At high stages, that is at the beginning of the pumping cycle, flow through the structure is at low velocity and with little flow separation occurring. At low stages, flow in the drop structure becomes highly turbulent resulting at first in entrainment of floating materials and at W.S. stages below -320 in entrainment of air into the duct. In the wet shaft, there appears to be no tendency for vortex formation or air entrainment into the suction header. Only the complete blockage of the lower portion of the bar screen caused a vortex in the wet shaft. It was recommended that three air vents be installed on the suction header at the intersection of each of the three branch pipe axis with the suction header wall. These vents will prevent air accumulation in the branch header during filling. Head losses throughout the structure were found to be small. They are summarized on pages 47 and 48. Piezometric grade lines are shown in Figs. 46, 47, and 48. A major grit deposition problem existed in the divided duct due to the large reduction in flow velocities and bed shear stresses in that part of the structure. A reduction in cross-sectional area by raising the invert by several feet resulted in a significant reduction in grit deposition. Complete elimination of grit deposition appears possible with further reductions of duct width.Item Experimental Flow Studies With the Dual-Screen Cooling Water Intake Assembly ("Riser") for the James H. Campbell Electric Power Generating Plant, Unit No. 3(St. Anthony Falls Laboratory, 1978-12) Stefan, Heinz G.; Dahlin, Warren Q.; Ripken, John F.; Wood, Addison; Winterstein, TomFlow characteristics inside and outside of a dual-screen cooling water intake assembly ("riser") for the James H. Campbell Unit No.3 were observed and measured in hydraulic models at scales of 1:3 and 1:12. Risers consist of dual cylindrical screens with horizontal axis and solid endplates mounted on a T-assembly which is supported by a 3.5 ft diameter vertical withdrawal pipe. Pressure losses within the assembly, approach flow velocity patterns and approach flow velocities on the screen surface were investigated. A total headloss coefficient of 4.6 resulting in an equivalent full-scale headloss of 8.0" of water at a withdrawal rate of 29.44 ofs through the assembly was measured in the model. Flow patterns towards single and multiple risers were observed by dye tracing techniques. Approach flow velocities were measured on the surface of the 1: 3 scale riser model. The highest velocities were found near the center of the screen and the lowest ones near the projecting endplates. Maximum local velocities exceeded calculated average velocity by about 30 per cent.Item Field Investigations of Water Temperature Stratification and Wind Effects on Dissolved Oxygen in Pool No. 2 of the Mississippi River(St. Anthony Falls Hydraulic Laboratory, 1976-12) Stefan, Heinz; Wood, AddisonDissolved oxygen, water temperatures, Secchi depth, and surface drift currents were measured in pool No. 2 of the Mississippi River during very low flow conditions from August 24 through September 25, 1976 on eleven different days and under significantly varied weather conditions. Water quality parameters were found to vary, both in time and space and in direct relationship to prevailing weather, particularly wind and sunshine. With total river flows from approximately 1000 to 2000 cfs, the measured D.O. distributions, water temperatures, and transparencies were predominantly typical of a series of interconnected lakes and to a lesser degree typical of a river. Natural convection, density currents, and wind drift were found to be of great importance. Recovery from low dissolved oxygen levels due to the effluent from the Metropolitan Waste Treatment Plant occurred in the pool upstream from Dam No. 2 mainly as the result of photosynthesis, surface aeration, and the hydrodynamic exchange processes between different regions of the pool.Item The Flow and Stability Characteristics of Alluvial River Channels(St. Anthony Falls Hydraulic Laboratory, 1975-09) Anderson, Alvin G.; Parker, Gary; Wood, AddisonAlluvial rivers, insofar as they transport the material of which their channels are composed, possess the freedom to alter their geometry through the phenomena of erosion and deposition. River channels can be loosely divided into bed and bank regions, and geometry alteration phenomena can likewise be divided into bed processes and bank processes. An analysis of bank processes is dependent on a general knowledge of bed processes. Bed processes associated with wide, equilibrium rivers, in which bank processes are negligible, are examined in Chapter I of this report. An attempt is made to find the most general possible forms for sediment transport and bed resistance relationships. The forms are general enough so that existing equations can be expressed within their framework. Bank processes, and in particular bank erosion, are the subject of the remainder of the report.