Design, Calibration, and Evaluation of a Trapezoidal Measuring Flume by Model Study

SCOPE AND PURPOSE OF INVESTIGATION The discharge occurring in an open channel can be measured by placing a constriction in the channel. Flumes are commonly used as constriction in open channels. A flume is a specially designed and calibrated section built into a channel, the physical properties of which allow the calculation of the discharge. The narrowest section of the flume is usually called the throat. The velocity of flow through the throat, for any given flow rate, increases with a decrease in the flow depth. The ideal condition for measurement of discharge is a throat sufficiently constricted to produce critical-depth in the throat. Whenever the geometry of a channel produces critical flow the relationship between discharge and head is independent of conditions downstream, making discharge a function of only the upstream depth. Thus, when critical-depth occurs in the throat, the only measurement required to determine the discharge through the flume is the upstream depth of flow, thus making the wide use of critical-depth flumes desirable for measurement purposes. Flumes of carious shapes are used to obtain a condition of critical-depth, the most common and well known being the Parshall flume. One purpose of this investigation has been to study the trapezoidal shaped flumes which several researches (Ackers and Harrison, 1963; Ludwig and Ludwig, 1951; Palmer and Bowlus, 1936; Robinson and Chamberlain, 1962; and Wells and Gotaas, 1948) have investigated. However, the primary purpose of this investigation has been the design, calibration, and evaluation, by model study, of a trapezoidal measuring flume to be constructed in the distribution system of the D.M.A.D. Company (Delta, Melville, Abraham, and Deseret Irrigation Companies) in Delta, utah. The flume to be constrcuted will be used to measure irrigation waters in a canal (Canal B ) having a capacity of 300 cfs (cubic feet per second) and located below the D.M.A.D. Dam. The essential objectives of the model study have been: (1) investigation of several entrance and exit conditions to obtain the most economical, efficient, and practical design, (2) correlation of the data from this study with that of previous research, and (3) comparison of head losses in trapezoidal flumes with those of rectangular and Parshall flumes. The trapezoidal flume has been designed as a critical-depth flume utilizing present tailwater conditions (the present depth-discharge relationship for Canal B is illustrated in Figure 1). However, increased developments by the D.M.A.D. Company in the channel downstream from the proposed flume may yield increased depth of flow for any particular discharge, thereby increasing the degree of submergence. In case the tailwater depths should rise much above the present levels for any particular discharge, submergence of the flume will undoubtedly occur and then two variables will have to be measured both the upstream and tailwater depths. Consequently, the calibration of the trapezoidal measuring flume was extended to submerged flow in this investigation. After the prototype structure has been constructed, a field calibration will be conducted. This field calibration will be compared with the calibration for the prototype structure as predicted from the model study. Neither the field calibration nor the comparison between the field and model prediction calibrations will be incorporated into this thesis

Evaluation of free and submerged flow data for large parshall flumes

Because the accurate measurement of water plays such an important part in water management, such structures as weirs, orifices, calibrated gates f and flumes have been developed. These structures provide the means for reasonable measurement of the smaller flows (1: .. 100 cfs), but for the large flows (100-3,000 cfs) the current meter, large Parshall flume, and various other flumes are commonly used. Where a permanent structure is required, the most widely accepted and utilized method for measurement of large flows is probably the Parshall flume. The purpose of this report has been to collect the existing flow data for large Parshall flumes having throat widths of 10, 12, 15, 20, 25, ,30, 40, and 50, feet, and evaluate from the data certain free flow and submerged flow relationships. The free flow relationships of large Parshall flumes as listed by R . L. Parshall (1932) are verifieq. from the data. The study reported herein was further made to illustrate that the analysis of submergence developed at Utah State University for smaller Parshall flumes (Skogerboe, Hyatt. Johnson, and England, 1965) is also applicable to large Parshall flumes

Designing a mobile augmented memory system for people with traumatic brain injuries

Augmented memory systems help people remember events in their lives. Individuals with Traumatic Brain Injury (TBI) often have memory impairments. We conducted a user study to learn about strategies individuals with TBI use to remember events in their lives. We explored what characteristics individuals with TBI expect of an augmented memory system. We then investigated these aspects in an initial mobile app design, and propose here a concept for a rehearsal application that addresses the issues found in our studies

Modifications to Gate-Flume Structures on the Weber Davis Canal

The turnout structures under study divert flows from the Weber-Davis Canal near Clearfield, Utah. A portion of the canal in this area was realigned as a result of the construction of the Interstate Highway System. The twin turnout structures, used to divert water to the West Branch Irrigation Company and West Layton Irrigation Company, were constructed in conjunction with the realignment of the concrete -lined canal. A three-dimensional drawing of the twin turnout structures is shown in Fig. 1. Water is diverted from the canal by passing under the discharge diverted through each of the structures is approximately 35 cfs (cubic feet per second, or second-feet). To properly allocate and assess the quantity of flow delivered to each of the irrigation companies, Parshall flumes having a throat width of four feet and a depth of four feet were placed inside each structure. After passing through the Parshall flumes, the water is conveyed by twin corrugated metal arch pipelines, located under the newly constructed freeway, to existing irrigation distribution systems which serve lands west of the highway. A portion of the twin turnout structures are covered with concrete (Fig. 3) to accommodate the service road located on the west side of the canal. One of the difficulties encountered in the design of the structures was the space available between the canal and the cut bank on the freeway right-of-way. This space limitation resulted in the entrance of the four-foot Parshall flume being located less than nine feet away from the diversion gate. The situation was further aggravated by placing the lip of the gate opening two feet lower than the bottom of the canal. The net result was a high velocity jet passing under the gate with maximum velocities reaching 15 feet per second. The high velocity jet resulted in considerable turbulence and wave action within the structure. The instability of the flow created concern regarding the reliability of the standard calibration for Parshall flumes in predicting the actual flow being diverted to each of the two irrigation companies. In an effort to reduce the height of waves, a metal stilling float was placed in each structure (Fig. 4). The floats did not materially improve the flow conditions

Subcritical Flow Over Highway Embankments

Introduction: At Utah State University, considerable effort has been devoted to the analysis of submerged flow at open channel constrictions. A method of analyzing subcritical (submerged) flow has been developed for flumes. Because of previous findings, it was felt that this method of analyzing submerged flow could be applied to highway embankments. A highway embankment, when overtopped by flood waters, is a form of broad-crested weir. Being a weir, the flood discharge over the embankment is only a function of the upstream depth for free flow conditions. This paper will present a method for determining the discharge under submerged flow conditions using the upstream and downstream depths. Thus, postflood 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. One of the earliest studies regarding flow over an embankment was reported by Yarnell and Nagler. More recent experimental data have been reported by Kindsvater. The data collected by Kindsvater have been reanalyzed in this paper according to recent developments. The experimental models studied by Kindsvater are comparable to a secondary highway embankment. The data resulting from the model studies have been subjected to the method of submerged flow analysis previously employed with flow measuring flumes. The consistency of the data, both for free flow and submerged flow, reflects the quality of the experimental design and procedures used in collecting the data. Although the data presented in this paper apply only to various forms of secondary road embankments, the method of analysis is general

Rectangular Cutthroat Flow Measuring Flumes

Introduction: Procedures and methods for more accurate measurement and improved management of water are continually being sought to make better use of our water resources. Of all the devices and structures developed for measuring water, measuring flumes are among the most widely accepted and used. The most common measuring flume is the Parshall flume developed by Ralph Parshall at Colorado State University. Common to most flumes is the basic geometry consisting of a converging inlet section, a throat, and a diverging outlet section. Occasionally, the diverging outlet section is removed under free flow conditions, and the water is allowed to jet directly from the throat section into the downstream channel. This is not always permissible, however, in unlined channels because of possible erosion problems. In flat gradient channels, a flume may be installed to operate under conditions of submerged flow rather then free flow in order to (1) reduce energy losses, and (2) allow placement of the flume on the channel bed to minimize the increase in water surface elevation upstream from the flume. The purpose of the research effort reported herein was to develop a flume which would operate satisfactorily under both free flow and submerged flow conditions

Analysis of Submergence in Flow Measuring Flumes

Submerged flow exists in a measuring flume when a change in flow depth downstream from the flume causes a change in flow depth upstream for any particular constant value of discharge. When a change in tailwater depth does not affect the upstream depth, free flow exists. To evaluate the discharge under free-flow conditions, it is necessary to measure only a flow depth upstream from the contracted section (throat) of the flume, whereas two flow depths must be measured to evaluate the discharge under submerged-flow conditions. The two flow depths normally measured when submerged flow exists consist of the same upstream depth used for free flow and a depth measured in the throat, although this need not be the case as will be shown later. Most of the earlier investigations regarding measuring flumes have emphasized the development of free-flow calibrations or ratings for various flume geometries. Notable free flow investigations have been made by V. M. Cone, Parshall, Engel, Khafagi, Robinson and Chamberlain, and Ackers and Harrison, to mention a few. Various methods of analyzing submerged flow have been presented by Parshall, Khafagi, Villemonte and Gunaji, Robinson and Chamberlain, and Robinson. Parameters describing submergence in flow-measuring flumes will be developed from dimensional analysis. A combination of empiricism and dimensional analysis will be used to develop a submerged flow discharge equation. The resulting discharge equation will be compared with the theoretical submerged-flow equation developed from momentum relationships. A rectangular flat-bottomed flow measuring flume was used to generate data necessary for establishing the parameters describing submerged flow. The form of the discharge equations describing submerged flow in a rectangular flume has been verified for a trapezoidal flat-bottomed flume, a rectangular flat-bottomed flume, and a Parshall flume

Development, characterization and dissolution behavior of calcium-aluminoborate glass wasteforms to immobilize rare-earth oxides

Calcium-aluminoborate (CAB) glasses were developed to sequester new waste compositions made of several rare-earth oxides generated from the pyrochemical reprocessing of spent nuclear fuel. Several important wasteform properties such as waste loading, processability and chemical durability were evaluated. The maximum waste loading of the CAB compositions was determined to be ~56.8 wt%. Viscosity and the electrical conductivity of the CAB melt at 1300 °C were 7.817 Pa·s and 0.4603 S/cm, respectively, which satisfies the conditions for commercial cold-crucible induction melting (CCIM) process. Addition of rare-earth oxides to CAB glasses resulted in dramatic decreases in the elemental releases of B and Ca in aqueous dissolution experiments. Normalized elemental releases from product consistency standard chemical durability test were <3.62·10-5 g·m-2for Nd, 0.009 g·m-2for Al, 0.067 g·m-2for B and 0.073 g·m-2for Ca (at 90, after 7 days, for SA/V = 2000m-1); all meet European and US regulation limits. After 20 d of dissolution, a hydrated alteration layer of ~ 200-nm-thick, Ca-depleted and Nd-rich, was formed at the surface of CAB glasses with 20 mol% Nd2O3whereas boehmite [AlO(OH)] secondary crystalline phases were formed in pure CAB glass that contained no Nd2O3