Browsing by Author "Silberman, Edward"

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Air Bubble Resorption
(St. Anthony Falls Hydraulic Laboratory, 1949-08) Silberman, Edward
This paper describes an analysis and experiment directed at determining the laws governing the rate of solution of a gas bubble in turbulent liquid. The object of the research was to determine methods for resorbing air bubbles which have been freed from the water in a water tunnel. A basic equation governing the resorption process which has been developed and partially verified in the work is presented as Eq. (13) in the text. Useful approximate forms of this equation are given as Eqs. (14b) and (14d) in the text. The basic equation has led to several suggested methods for accomplishing resorption in water tunnel. These include: (1) a resorber method already developed at the California Institute of Technology[1]*; (2) a method in which air in solution in water would be completely replaced in the closed water tunnel circuit by another gas such as carbon dioxide; and (3) a method in which a lengthened return circuit would be combined with a fin-scale turbulence, introduced in the return circuit to hasten air bubble resorption while keeping the bubble from rising. The time required for resorption by any of these methods may be estimated from the basic equation.
Air-Water Mixture Flow Through Orfices, Bends, and other Fittings in a Horizontal Pipe
(St. Anthony Falls Hydraulic Laboratory, 1960-09) Silberman, Edward
In planning piping systems for flow of gas-liquid mixtures, it is necessary to know something about the pressure and the pressure changes along the line. The pressure changes may be considered partly frictional and partly nonfrictional. Both of these mechanisms are active in mixture flows in straight, uniform pipes, and in fittings with gradual changes in cross section and/or alignment such as diffusers and bends. In fittings with abrupt changes in cross section, such as orifices, frictional losses are relatively small and pressure changes are largely the result of changes in kinetic energy and momentum. Furthermore, the flow pattern (that is, whether the flow be bubble, plug, annular, etc.) is dependent on the local pressure, other factors being constant, and it may be desirable to mow something about the flow pattern for use in heat transfer calculations, for example, and even for use in calculations for pressure drop in some fittings.
The Effect of Tube Vibrations on Flow Through Tubes
(St. Anthony Falls Hydraulic Laboratory, 1951-11) Silberman, Edward
This paper presents an approximate analysis and an experimental investigation of the effect of external vibration of flow in tubes. Only flow in straight tubes of uniform cross section was considered. It is shown that external vibration of the tube produces small fluctuations, it was found both by analysis and by experiment that the pressure drop in steady flow was not increased and that there was no delay in flow establishment after opening a valve. An incidental result of this investigation was the experimental finding that laminar flow in tubes at Reynolds numbers up to 15,000 was stable to all small external disturbances. This finding was applicable to both the fully developed region and the region of developing boundary layer beyond at least 60 tube diameters from the entrance.
An Experimental Investigation of the Effect of Drag Reducing Polymer Additives on Surface Pressure Fluctuations on Bodies of Revolution with Rough Surfaces Moving through Water
(St. Anthony Falls Hydraulic Laboratory, 1978-05) Silberman, Edward
A sound detector in the surface of a moving body receives not only sound signals radiated from a distant source but also detects pressure fluctuations originating in the turbulent boundary layer of the fluid surrounding the body. The purpose of the present work was to assess the magnitude of the surface pressure fluctuations on a body moving in water and in water with polymer additive under nearly zero pressure gradient conditions. Measurements were made using a single transducer in the surface of an axi-symmetric body. Both smooth and grit-roughened surfaces were used. Mean square pressure fluctuation amplitudes were measured as a function of frequency, non-dimensionalized, plotted, and compared with some results obtained by others in both water and air. It was concluded that the addition of roughness to a smooth surface increases the amplitude at the peak of the spectrum and at all lower frequencies. Polymer additive in the water has just the opposite effect on a rough-surfaced body, decreasing the amplitude at the peak and at all lower frequencies, the reduction increasing monotonically with drag reduction. There was little or no effect at high frequencies attributable to either roughness or polymer additive, but it must be noted that the transducer used was too large to obtain a true measure of amplitude at the highest frequencies. The peak of the spectrum in water appears to have a somewhat higher amplitude than it does in air.
Experimental Studies of Cavitation Noise in a Free-Jet Tunnel
(St. Anthony Falls Hydraulic Laboratory, 1961-07) Song, C. S.; Silberman, Edward
The present paper summarizes the results of experimental studies on cavitation noise generated in the free-jet tunnel at St. Anthony Falls Hydraulic Laboratory in the period October 1960 to June 1961. Two-dimensional test bodies of different shapes, such as a circular cylinder, wedge, and a Tulin-Burkhart hydrofoil were tested. Various types of cavitating flows, namely, transient cavities, steady-state cavities, and non-stationary cavities were covered. Special attention was given to the effect of ventilation on the intensity of cavitation noise. Effects of body size and the presence of a solid boundary were also investigated.
Experimental Studies of Supercavitating Flow About Simple Two-Dimensional Bodies in a Jet
(St. Anthony Falls Hydraulic Laboratory, 1958-04) Silberman, Edward
A two-dimensional free-jet water tunnel is described briefly. Results of experimental measurements on a two-dimensional cup, symmetrical wedges, inclined flat plates, and a circular cylinder in the tunnel are given. Measured force coefficients at zero cavitation number are in good agreement with theory. Shapes of the cavities were computed for one of the wedges and for one of the plates at zero cavitation number; the observed shapes are also in good agreement with the theory. For nonzero cavitation numbers, theoretical results for force coefficients were available for comparison in only two cases. For one of these, the cup, agreement between theory and experiment was good up to a cavitation number of about 0.5. For the other, a symmetrical wedge, experimental results were compared with a linear theory with good agreement for cavitation numbers between about 0.1 and 0.3. In the case of the wedge, measured cavity lengths were somewhat shorter than predicted by the linear theory. All other comparisons with theory at nonzero cavitation number had to be made with the theory as developed for infinite fluid. The experimental force coefficients were less than predicted by infinite-fluid theory, but tended to approach the theoretical values as the cavitation number increased. A similar tendency marked the comparison between the experimental data and data taken by others in closed tunnels.
Experiments on a Jet Flap in Supercavitating Flow
(St. Anthony Falls Hydraulic Laboratory, 1964-01) Silberman, Edward
Experiments on a fully-cavitated, flat-plate hydrofoil equipped with a pure jet flap were conducted in the free-jet water tunnel at the St. Anthony Falls Hydraulic Laboratory. The foils were of 2-in. and 2.75-in. chord and were tested in 6-in., 10-in., and l4-in. wide free jets. Data were obtained on the increments in lift, drag, and moment coefficients and on the shift in center of pressure as a function of jet momentum coefficient C_j, cavitation number, and other variables.
Extended Phase A-2, Large Cavitation Channel, Davld Taylor Naval Ship Research and Development Center
(St. Anthony Falls Laboratory, 1984-08) Arndt, Roger E. A.; Song, Charles C. S.; Silberman, Edward; Killen, John M.; Wetzel, Joseph M.; Yuan, Mingshun
It was suggested that a mild contraction located immediately upstream of the pump may improve the quality of flow which is expected to be quite nonuniform coming from the diffuser and the first and second elbow. To investigate the effect of the contraction ratio, the AROl computer model previously used in the Phase A-2 studies for the Large Cavitation Channel (LCC) main contraction design was applied to the pump contraction. As shown in Fig. 1, the contraction is assumed to be 5.563 m long and of circular cross section. Area contraction ratios of 0, 10, 20 and 30 percent were used. There is a fixed shaft of constant diameter along the centerline of the contraction. Two different shaft diameters, 0.508 m and · 1.016 m, were used based on information available at the time the study was conducted~ Initially, a fifth order polynomial was used for the contraction profile. The profile was later changed to a straight line because the contraction is so mild that the flow is not significantly affected by the boundary shape. Due to symmetry about the vertical plane, only half of the flow region was modeled. Different types of nonuniform inflow velocity profiles were studied. A total of 46 modeling runs covering various geometrical and flow conditions as well as different modeling parameters were made.
Fluid Flow Diversion by Guide Vanes in Miter Bends
(St. Anthony Falls Hydraulic Laboratory, 1949-04) Silberman, Edward
A search of existing literature revealed several papers dealing with experimental investigations of specific vaned turns and others which approached the problem analytically. None of these, however, outlined general criteria for design and performance of guide vane cascades in miter bends which would be applicable to new installations. Such criteria have been established in this paper.
Friction Factors for Helical Corrugated Aluminum Pipe
(St. Anthony Falls Hydraulic Laboratory, 1969-12) Silberman, Edward; Dahlin, Warren
The St. Anthony Falls Hydraulic Laboratory was engaged by the Aluminum Association to determine the friction factors for fully developed flow in helical corrugated pipe of several sizes.
Further Studies of Friction Factors for Corrugated Aluminum Pipes Flowing Full
(St. Anthony Falls Hydraulic Laboratory, 1971-04) Silberman, Edward; Dahlin, Warren
The St. Anthony Falls Hydraulic Laboratory was engaged by Chamlin and Associates, Inc., of Peru, Illinois, to determine the friction factors for fully developed flow in several sizes of annular and helical corrugated pipes flowing full and to make qualitative observations of the pipe joint characteristics.
Further Studies of Friction Factors for Helical Corrugated Aluminum Pipes with Re-Corrugated Annular Rings on Each End
(St. Anthony Falls Hydraulic Laboratory, 1976-03) Dahlin, Warren; Silberman, Edward
The St. Anthony Falls Hydraulic Laboratory was engaged by Kaiser Aluminum and Chemical Sales, Inc., to determine the friction factors for fully developed flow in 24 and 12 in. helical corrugated pipes flowing full and to make qualitative observations of the pipe joint characteristics. These pipes are unique in that the pipes were manufactured by customary procedures for helical pipe and then the ends re-corrugated with four annular rings using a special machine. The pipe characteristics are given in Fig. 1 and the physical features are shown in Figs. 2 and 3. The purpose of the re-corrugated pipe ends is to make it more convenient to connect the pipes together under field conditions.
Generation of Air-Water Mixtures in Colsed Conduits by Aspiration
(St. Anthony Falls Hydraulic Laboratory, 1954-12) Silberman, Edward; Ross, James A.
This report describes a theoretical and experimental investigation of aspirator-type generators for producing air-water mixtures in closed conduits. As a necessary corollary, some theoretical and experimental work was also performed on the flow of air-water mixtures in closed conduits downstream of the aspirator. The aspirator-type of air-water mixture generator was chosen for this study after a preliminary investigation because it gave a promise of producing large air-water ratios and some control of bubble size. The control of bubble size did not prove to be as great as was anticipated from the preliminary work, but there was no problem in achieving large air-water ratios. It is shown that aspirators should generally be designed without diffusers, both to save cost and to facilitate design using theoretical equations. The appropriate equations are developed. Experimental data are presented and compared with the theory, verifying it essentially. Bubble sizes, although correlated by the theory, are not predictable from it and must be obtained by experiment. Although the present experiments were confined to air-water mixtures, the theory is generally applicable to all liquids and gases.
Hydraulic Model Studies for a Cooling Tower Circulating Water System Callaway Plant Unit - Union Electric Company
(St. Anthony Falls Hydraulic Laboratory, 1977-04) Silberman, Edward; Dahlin, Warren
The water basin under a large cooling tower can serve as a storage reservoir to balance flows through the plant condenser system, overcoming variations in evaporative losses and make up water availability. To use the storage capability effectively requires that some attention be given to the hydraulic design details of the basin and the channel leading from it to the circulating water pump pits. This model study has been undertaken to examine a design for that system for one of the cooling towers at the Callaway Plant Unit of the Union Electric Company.
Hydraulic Study for Storm Sewer Outlet
(St. Anthony Falls Hydraulic Laboratory, 1977-03) Silberman, Edward
A storm sewer is planned to discharge into the Mississippi River from its west bank just below St. Anthony Falls. The sewer pipe is 12 ft in diameter and its centerline will make an angle of about 60° with the river bank at the point of discharge. At that point the river is used by barges approaching a lock at the Falls. The water level is closely controlled at 750 ft, MSL. It is required that sewer discharges should not produce local mean crossflow velocities in the river in excess of 4 fps at a sewer design discharge of 1700 cfs nor in excess of 2 fps at the more likely discharge of 500 cfs. The river bed is sandstone at elevation 739.3 ft MSL and the sewer invert has been designed to intersect the river bank at that elevation. Because of the rook, it is desired to diffuse or spread the flow horizontally at the sewer outlet to achieve the required velocities rather than to dissipate energy in a conventional stilling basin. The sewer pipe is laid on a straight tangent of at least 600 ft length at a uniform slope, of 0.001 before reaching the river.
Importance of Secondary Flow in Guide Vane Bends
(St. Anthony Falls Hydraulic Laboratory, 1953-01) Silberman, Edward
For purposes of analysis, the flow in a guide vane bend is divided into a basic or primary two-dimensional flow with superimposed secondary flow. The two-dimensional flow is reviewed briefly first. It is then shown from experimental data that, for practical purposes, the secondary flow has negligible influence on the two-dimensional deflection, but the two-dimensional head loss is increased materially by the secondary flow. The effect of the secondary flow on head loss can be divided into two parts. The first part causes a loss which can be measured immediately behind the vanes, while the second part causes a loss which occurs between the trailing edges of the vanes and a plane about 4 duct hydraulic diameters behind the miter line of the bend. The second part is considerably larger than the first and may be attributed to increased wall shear downstream of the vanes. The increased wall shear is, in turn, attributable to the redistribution of streamlines by the secondary flow.
Model Studies for the Spillway and Outlet Works of the Yguazu Dam
(St. Anthony Falls Hydraulic Laboratory, 1972-08) Silberman, Edward; Bowers, C. Edward
A hydroelectric power plant presently exists on the Acaray River in Paraguay where it joins the Parana River. It is proposed to increase the generating capacity of this plant by regulating the flow of a tributary of the Acaray, the Yguazu. A dam would be built on the Yguazu near its junction with the Aoaray for this purpose.
Model Studies Of The Cooling Water Outlet Channel From The Allen S. King Generating Plant To Lake St. Croix
(St. Anthony Falls Hydraulic Laboratory, 1966-07) Silberman, Edward; Dahlin, Warren Q.
The Northern States Power Company is building the Allen S. King Generating Plant, a thermal plant, on Lake St. Croix between Stillwater and Bayport, Minnesota. Operation of the plant requires that water be drawn from Lake St. Croix, used for condenser cooling purposes. and then discharged essentially unchanged except with a higher temperature, back into Lake St. Croix at a location downstream from the intake. The first unit of the plant, requiring 660 cfs of condenser cooling water, is now under construction. It is planned to add a second unit later making a total requirement for condenser cooling of 1500 cfs. Pioneer Service and Engineering Company is designing the plant.
A Model Study of a Dike Enclosure at the Eastern End of Lake Erie
(St. Anthony Falls Hydraulic Laboratory, 1969-04) Silberman, Edward; Dahlin, Warren; Paintal, Amreek
The Bethlehem Steel Corporation is faced with the problem of finding a disposal area for solid wastes, principally slag, from its steel plant at Lackawanna, New York. Whereas the slag was previously dumped freely into Lake Erie, such dumping is now considered undesirable. The company has proposed that a diked enclosure be built into the lake opposite its plant and that the wastes be dumped into this enclosure, thus preventing them from entering the lake. The company has estimated that the dike should enclose about 620 acres to accommodate its needs to some reasonable future date.
Model Study of the Intake and Discharge Structures for Zion Nuclear Station
(St. Anthony Falls Hydraulic Laboratory, 1969) Silberman, Edward; Hayden, John
The Zion Nuclear Station, being built by the Commonwealth Edison Company on Lake Michigan, was designed by Sargent and Lundy of Chicago, Illinois. The plant requires condenser cooling water flows of 3450 cfs during midsummer. Harza Engineering Company, also of Chicago, acted as consultants on the hydraulic design of the intake and discharge structures and determined that a model study would be desirable for checking some of the hydraulic features of these structures. The model studies were conducted at the St. Anthony Falls Hydraulic Laboratory. This report describes the studies and the results thereof.

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