Subcritical Flow at Open Channel Structures Open Channel Expansions

Analyzing the hydraulics of open channel constrictions has been modified to allow the analysis of energy loss in open channel expansions. The modified technique has been compared with previous methods of analysis using data collected in the laboratory on open channel expansions with vertical walls, and triangular-shaped baffles. Also, a design procedure for such baffled outlet structures has been developed

Subcritical Flow Over Various Weir Shapes

Submerged flow exists for any given structure when a change in flow depth downstream from the structure causes a change in flow depth upstream from the structure for any given constant value of discharge. The two flow depths, normally measured when submerged flow exists, consist of a depth upstream from the structure, which is used also for free flow conditions, and a depth of flow located any place downstream from the structure. The initial studies in which the submerged flow analysis was developed were made on flat-bottomed flumes (Hyatt, 1965; and Skogerboe, Walker, and Robinson, 1965). Later studies verified the method of analysis for Parshall flumes (Skogerboe, Hyatt, England, and John son, 1965; and Hyatt, Skogerboe, and Eggleston, 1966). Because of previous findings, it was felt this method of analyzing submerged flow could be applied to various types and kinds of weirs. Original development of the parameters and relationships which describe submerged flow came from a combination of dimensional analysis and empiricism. Further verification of the parameters developed in this manner are obtained by employing momentum relationships. Both approaches to the submerged flow problem are discussed in this report. Considerable effort and study has been expended on free and submerged flow weirs by other authors in previous years. For this reason the authors of this report went to the literature as a source of data. Various studies typifying a particular type of weir structure were investigated and the data selected from these studies were subjected to the submerged flow analysis developed by the authors. The data from these studies provide further verification of validity of the approach to the submerged flow problem made by the authors. Acknowledgement is given and appreciation expressed to those authors whose studies provided the data used in the analysis presented in this report. Although no investigation was made of a contracted weir, the authors feel that the submerged flow analysis as explained in this report would be just as valid for this type of structure

Stage-Fall-Discharge Relations For Flood Flows Over Highway Embankments

At Utah State University, considerable effort has been devoted to the analysis of submerged flow at open channel constrictions. A method of analyzing submerged flow was first developed for a trapezoidal flume by Hyatt (1965). Later studies verified the method of analysis for a rectangular flume (Skogerboe, Walker, and Robinson, 1965) and Parshall flumes (Skogerboe, Hyatt, England, and Johnson, 1965). Because of the previous findings, it was felt this method of analyzing submerged flow could be applied to highway embankments. A highway embankment is a form of broad-crested weir when overtopped by flood waters. Being a weir, the flood discharge over the embankment is only a function of the upstream depth for free flow conditions. This report will present a method for determining the discharge under submerged flow conditions using the upstream and downstream depths. Thus, post flood field measurements and observations, when properly obtained, will provide the necessary information for an accurate determination of the flood discharge for either free or submerged flow conditions. The concepts involved in the analysis of submerged flow at open channel constrictions were originally developed by dimensional analysis for flow measuring flumes. The parameters describing submerged flow in flumes have been further verified by the development of theoretical submerged flow equations which utilize momentum theory and energy relationships. The experimental models studied by Kindsvater (1964) are comparable to a secondary highway embankment. The models were constructed to a scale of 1/9 a typical secondary roadway. The data resulting from the model studies has been subjected to the method of submerged flow analysis previously employed with flow measuring flumes. The consistency of the data, both fro free flow and submerged flow, reflects the quality of the experimental design and produces employed in collecting the data. Although the data presented in this report applies only various forms of secondary road embankments, the methods of analysis are general. The development of calibration curves for other embankment geometries requires only the generation of additional data employing model studies

Subcritical Flow at Open Channel Structures Bridge Constructions

The techniques previously employed by the writers for describing subcritical flow at open channel constrictions have been found valid for analyzing nonuniform flow in open channels. Combining the nonuniform flow analysis with the submerged flow ratings for various bridge geometrics has provided an analytical means for determining the backwater due to the bridge constrictions under “abnormal stage – discharge” conditions

Rating Flow Regulation Structures in the Bear River Canal System

Introduction. The Bear River Canal System (Fig. 1) is located below Cutler Reservoir in Box Elder County, Utah. The average annual quantity of water conveyed through the canal system is approximately 230,000 acre-feet. Any water not consumptively used in this area eventually flows in to Great Salt Lake. Utah Power and Light Company has the rights to the waters stored in Cutler Reservoir for operating a hydroelectric plant. The irrigation distribution system below the reservoir is operated and maintained by the Utah-Idaho Sugar Company. The water is delivered to the water users through the distribution system and a nominal maintenance charge is assessed each user

Analysis of Small Water Management Structures in Irrigation Distribution Systems

The Irrigation and Drainage Research Conference conducted at Utah State University (ASCE, 1964) delineated many of the research needs regarding “Small Low- Cost Hydraulic Structures for Conveyance and Distribution Systems,” which was one of the six topics considered at the conference. In discussing possibilities for accomplishing the recommended research, it was suggested by some panel members that a considerable portion of the work could be undertaken by graduate students, particularly at the Master of Science level. The intent of this report has been to sort through the large volume of literature in an attempt to define the specific research needs regarding small water management structure used in irrigation distribution systems. In particular, the emphasis has been to develop specific research topics which could be accomplished as a thesis by a graduate student at the Master of Science level

Feasibility of Rating Current Meters in a Velocity Field

Preliminary studies employed an 8-inch (outlet diameter) contracting cone and an 8-inch converging nozzle. The design of the cone is based on an electromagnetic analogy reported by Smith and Wang, while the nozzle was designed assuming potential flow and using numerical methods to obtain the solution. Both designs yielded fairly uniform velocity fields, any deviations being primarily due to either construction or measurement techniques. The towing tank rating for a Pygmy current meter was compared with the submerged jet rating, the difference being 1 or 2 percent. A Prototype system was constructed using a 16-inch contracting cone (d). Two Type AA Price current meters were rated in this facility. The hydraulic performance of the system proved very satisfactory, illustrating that rating current meters in a submerged jet emanating from a contracting cone is feasible

Error Rate of the Kane Quantum Computer CNOT Gate in the Presence of Dephasing

We study the error rate of CNOT operations in the Kane solid state quantum computer architecture. A spin Hamiltonian is used to describe the system. Dephasing is included as exponential decay of the off diagonal elements of the system's density matrix. Using available spin echo decay data, the CNOT error rate is estimated at approsimately 10^{-3}.Comment: New version includes substantial additional data and merges two old figures into one. (12 pages, 6 figures

Gravitational Waves From Known Pulsars: Results From The Initial Detector Era

We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom