Cutthroat Flume Research Articles

Water-use-Efficiency in Spring Mung bean (Vigna radiata L.) as Affected by Fertilizer Combinations and Planting Pattern Under Arid Conditions

This research trial was conducted to evaluate the effect of planting pattern and fertilizer doses on Water-use-Efficiency of spring planted Mungbean (Vigna radiata L.) on sandy loam soil under arid conditions at Main Line Lower Land Reclamation and Research Station, Bhakkar during spring season 2018. The trial was laid out in RCB design with split plot arrangement having three replications. The main plot consisted of four fertilizer (NPK) doses (30:60:15, 60:120:30, 90:180:45, 120:240:60kg ha-1) while the sub plot consisted of six planting patterns viz., 30, 45 & 60 cm (straight sowing) and 30, 45 & 60 cm cross sowing by applying half seed in horizontal direction and remaining half seed in perpendicular direction on sandy loam soil. Two irrigations were applied in a measured amount by the Cut throat flume during the whole life period of crop. Data was collected on number of plants (m-1), plant height, number of branches (plant-1), number of fruit bearing branches (plant-1), number of pods (plant-1), number of grains (pod-1), 1000-grain weight, biological, straw and grain yield. Almost all parameters were significantly affected by fertilizer doses, planting patterns and their interactions as well, except number of fruit bearing branches, number of grains (pod-1) and 1000-grain weight. Statistical analysis of data revealed that maximum grain yield (3180 kg ha-1) with net return Rs.157,312 and BCR 2.61 of spring planted mung bean was obtained by applying fertilizer before sowing @ 60:120:30 kg NPK ha-1 and sowing crop in first week of March in 60 cm apart cross lines by applying half seed in horizontal direction and remaining half seed in perpendicular direction on sandy loam soil under arid conditions.

On‐farm performance evaluation of small‐scale irrigation schemes in the Ethiopian Rift Valley: Internal and external performance process approach

AbstractThis study evaluated the on‐farm performance of two small‐scale irrigation schemes, Furfuro and Bedene Alemtena (hereafter referred to as Bedene), in the Ethiopian Rift Valley. Two sets of performance indicator parameters were used. The first group was internal performance indicators, which included conveyance, water application and application uniformity. The water flow velocity through canals was monitored using the floating method. The amount of irrigation water applied to the fields was measured using a cutthroat flume. The second group was external performance indicators, including agricultural performance, water use performance and physical sustainability indicators. The results indicated that Furfuro had average conveyance, application and uniformity efficiencies of 84%, 59% and 50%, respectively, while that of Bedene were 79%, 63% and 55%, respectively. The overall efficiencies for both schemes were about 49%, which is lower than the minimum permissible values. The outputs per irrigation supply and consumed water for Furfuro were 0.14 and 0.16 US$/m3, respectively, and they were 0.11 US$/m3 for Bedene. The relative irrigation and total water supply of Furfuro were 1.21 and 1.20, respectively, indicating the presence of excess water in the command area during the study season. The relative irrigation and water supply of Bedene was 0.81, which indicated that the scheme was water deficient. Irrigation water management practices need improvement in the two schemes.

Review of hydraulic performance of open‐channel flow‐measuring flumes

The review explored various flumes used for open channel flow measurement and provided insight into operational concepts, discharge measurement, range of flow, head loss requirements, degree of accuracy and submergence, advantages, and limitations for use. The reviewed flumes included; Parshall flumes, Montana flumes, Cutthroat flumes, H-flumes, Trapezoidal flumes, Replogle-Bos-Clemmens (RBC) flumes, Palmer-Bowlus flumes and Central Baffle flumes (CBF). Based on the stage and discharge relationship, the reviewed flumes have a reasonable accuracy of ± 10 % over a wide range of flows. RBC flumes are the most accurate flumes (± 2 %). For flows that deal with a lot of sediments, most flumes have self-cleaning capability except for Palmer-Bowlus flumes and Central Baffle flumes. H-flumes have low resistance to submergence. The submergence transition for H-flumes is only 25-30 %. RBC flumes and Palmer-Bowlus flumes have the highest submergence (90 %). CBF and Palmer-Bowlus flumes need to be improved in order to have self-cleaning capability. Submerged flow corrections need to be developed and published for Palmer-Bowlus flumes and RBC flumes. The reviewed flumes effectively operate with a minimal head loss. The review has provided an insight on selection of an appropriate type of flume for flow measurement in open channels.

Study on the applicability of four flumes in small rectangular channels

Different experiments and numerical simulation research were carried out in order to explore the hydraulic characteristics and applicability of the cutthroat flume, NACA airfoil-shaped flume, airfoil pillar-shaped flume, and optimized airfoil-shaped flume in rectangular channels. The four flumes with contraction ratios of 0.4, 0.5, and 0.6 in rectangular channels were tested under 144 free-flow conditions. Based on the Fluent software, standard k-ε three-dimensional turbulence model and volume of fluid (VOF) method were utilized for numerical simulation in each working condition. The principle of critical flow was used to analyze the correlation between the discharge, the contraction ratio, and the upstream water depth. This correlation was used to obtain the discharge calculation formulas of the cutthroat flume, NACA airfoil-shaped flume, airfoil pillar-shaped flume, and optimized airfoil-shaped flume in rectangular channels. The Froude number in front of the flume, the backwater height, the critical submergence degree, the velocity distribution, the head loss, the discharge measurement formula, and the accuracy were studied and compared. It can be concluded from the results that the cutthroat flume, NACA airfoil-shaped flume, airfoil pillar-shaped flume, and optimized airfoil-shaped flume all have good applicability in rectangular channels. Moreover, the hydraulic characteristics of all the four flumes meet the water measurement specifications in the irrigation area. The upstream Froude number of the NACA airfoil-shaped flume is the smallest, whereas the backwater height and head loss of the cutthroat flume and optimized airfoil-shaped flume are the smallest. It is also worth noting that the critical submergence degree of the optimized airfoil-shaped flume is the highest, with an average value of 0.85. The discharge measurement formulas of the four flumes have been deduced using the correlation between the discharge, the contraction ratio, and the upstream water depth. It was found that the average errors between the calculated discharge and the measured discharge of the four flumes are 3.17%, 2.17%, 1.53%, and 2.29%, respectively, which are less than 5%, and therefore meet the discharge measurement requirements. In the agricultural irrigation system and flow monitoring system, the hydraulic characteristics of the four flumes can provide a reference and basis for the selection of flumes in the rectangular channel.

Calibration 7" – Cutthroat Flume as New Size for Discharge Measurement at Free Flow Condition

This paper aims to conduct a series of laboratory experiments in case of steady-state flow for the new size 7 ̋ throat width (not presented before) of the cutthroat flume. For this size, five different lengths were adopted 0.535, 0.46, 0.40, 0.325 and 0.27m these lengths were adopted based on the limitations of the available flume. The experimental program has been followed to investigate the hydraulic characteristic and introducing the calibrated formula for free flow application within the discharge ranged between 0.006 and 0.025 m3/s. The calibration result showed that, under suitable operation conditions, the suggested empirical formulas can accurately predict the values of discharge within an error ± 3%.

Impact of Channel Slope on Cutthroat Flume Performance

Abstract. Cutthroat flumes are widely used in field projects to estimate discharge via a stage-discharge relationship. Flumes are commonly tested and calibrated in a laboratory to develop the stage-discharge relationship, but field installations often occur under non-idealized conditions, specifically with respect to bed slope. We calibrated a cutthroat flume with dimensions of 0.91 m length and 0.35 m throat width for bed slopes ranging from 0% to 2% to represent a range of field conditions. The experiment was conducted in the Water Resources Lab of the College of Engineering at the University of Wyoming, which provided highly accurate discharge measurements. Results showed negligible impact of slope on the resulting stage-discharge relationship under free flow conditions. We were able to generate a composite rating curve for bed slopes ranging from 0% to 2% for flumes of this size. Our study indicates that, under free flow conditions, longitudinal floor slopes ranging from 0% to 2% do not significantly affect the cutthroat flume rating curve. Keywords: Cutthroat flume, Flume calibration, Free flow, Rating curve, Stream discharge.

Three-dimensional numerical simulation of flow in trapezoidal cutthroat flumes based on FLOW-3D

Three-dimensional numerical simulation of flow in trapezoidal cutthroat flumes based on FLOW-3D

Dimensionless Discharge in Supercritical Flow Regime for Different Sizes of Cutthroat Flumes

Cutthroat flume is a flow measuring device which is commonly used for measurement of open-channel flow because of simple geometry and ease of construction. No experimental data are available for measurement of flow in the supercritical regime by cutthroat flume. Three different sizes of cutthroat flumes having different lengths and throat widths are fabricated and tested in the laboratory for supercritical flow regime. Regression analysis of experimental data is carried out, and it is observed that good correlation between dimensionless discharge and dimensionless head is obtained. Based on these results relation for dimensionless discharge and coefficient of discharge is proposed.

Measurement of flow in supercritical flow regime using cutthroat flumes

Cutthroat flume is commonly used for measurement of subcritical flow in open channel because of its simplicity and ease of construction. No experimental data is available in literature for measurement of flow in supercritical regime using cutthroat flume. The present paper finds the feasibility of cutthroat flume as a measurement device for flow in supercritical regime. Experimental data are generated to develop the relation between discharge and observed head at a specified location on upstream of throat section. Regression analysis for discharge and head indicated a good correlation. Based on all the experimental data generated, a relationship between discharge and head is proposed.

Design and analysis of 0.127 m (5″) Cutthroat flume

Abstract The aim of the present work was to perform series of detailed laboratory experiments under steady-state flow conditions through a Cutthroat flume of throat width 0.127 m (5″) and length 0.918 m. It is very important to perform research and propose equations for Cutthroat flume of throat-width 5″ as very rare work could be found on Cutthroat flume of this dimension. Experiments were conducted in laboratory designed and constructed 5″ throat width Cutthroat flume. Free flow and submerged flow calibrations were done within flow range of 0.005–0.0267 m3/s. Equations applicable for both free flow and submerged flow regime were proposed and Ditchrider’s table for field implementation of the flume was prepared. Results of the calibration show that under favorable operating conditions of the discharge within calibrated flow, the proposed equation can determine accurately the discharge with maximum error up to +5% in both free flow and submerged flow regime.

Modelling Furrow Irrigation-Induced Erosion on a Sandy Loam Soil in Samaru, Northern Nigeria.

Assessment of soil erosion and sediment yield in furrow irrigation is limited in Samaru-Zaria. Data was collected in 2009 and 2010 and was used to develop a dimensionless model for predicting furrow irrigation-induced erosion (FIIE) using the dimensional analyses approach considering stream size, furrow length, furrow width, soil infiltration rate, hydraulic shear stress, soil erodibility, and time flow of water in the furrows as the building components. One liter of water-sediment samples was collected from the furrows during irrigations from which sediment concentrations and soil erosion per furrow were calculated. Stream sizes Q (2.5, 1.5, and 0.5 l/s), furrow lengths X (90 and 45 m), and furrow widths W (0.75 and 0.9 m) constituted the experimental factors randomized in a split plot design with four replications. Water flow into and out of the furrows was measured using cutthroat flumes. The model produced reasonable predictions relative to field measurements with coefficient of determination R 2 in the neighborhood of 0.8, model prediction efficiency NSE (0.7000), high index of agreement (0.9408), and low coefficient of variability (0.4121). The model is most sensitive to water stream size. The variables in the model are easily measurable; this makes it better and easily adoptable.

3-D Numerical Simulation of the Flow Field of Cutthroat Flume

For cooperating with automation of flow measurement in irrigation districts, the method of flow measurement needs to be improved. Considering that sedimentation may appear at most channels and comparing with common water measure equipment, cutthroat flume measuring flume become the most suitable flow measurement structure adopted in irrigation districts with the advantages of the simple structure, the lower upstream backwater, not easy to silt the flume and so on. In the background of the cutthroat flume of one channel in the Ye River irrigation district of Shijiazhuang and on the basis of RNG k-εturbulence model, the 3-D numerical simulation of the flow field of cutthroat flume is carried out to obtain the distribution of velocity field and pressure field. By comparing the calculation value of nodal velocity with the measured value of nodal velocity, the reliability of the result of numerical simulation is proved. The above conclusions provide theoretical basis for further optimization design of cutthroat flume.

Nonlinear Regression Analysis for Programming and Engineering Application

Aiming at the calculating the flow of cutthroat flume in Hydraulic Engineering, the test data is processed through the nonlinear regression analysis program which is based on the principle of least square method. With 33 equations of various functions including linear, power function curve and exponential curve to be selected as the mathematical model, the regression analysis is taken through 33 equations. Comparing the regression coefficient from analysis, the optimal mathematical model is selected as the empirical formula, which has great significance in guiding the practical engineering.

Generic unified rating for Cutthroat flumes

Computational fluid dynamics (CFD) software was used to generate water depth and discharge data for the 24 standard-size Cutthroat flumes (CTF), as well as an additional 27 intermediate sizes. The hydraulic model was validated using information from several sources, including physical model test data for 16 standard sizes and 3 intermediate sizes. Grid-size independence was also confirmed for a range of computational cell sizes, and the calibration results for 16 of the standard-size flumes were compared with previously published calibration parameters. Through the CFD simulations, a full set of calibration and validation data was generated for each of the 51 tested flume sizes, filling the gaps in the experimental data from physical models and permitting a full analysis of flume hydraulic performance. The study resulted in a “generic” (any CTF in the dimensional range of the 24 standard sizes and specified dimensional ratios according to the original design criteria) and “unified” (for both free- and submerged-flow conditions) calibrations. From these results, a single algebraic equation was developed for free and submerged flow, relating upstream water depth and submergence to discharge. The error in the CFD-predicted discharge for all flume sizes is less than 3 % of the full-scale discharge, and the equation is applicable to both standard and nonstandard sizes.

Generic Free-Flow Rating for Cutthroat Flumes

Computational fluid dynamics (CFD) software was used to generate water depth and discharge data for 51 Cutthroat flume sizes, including all 24 standard sizes published by the flume's developer and 27 intermediate sizes. The hydraulic model was validated by using data from several sources, including physical model testing for 15 standard sizes and three intermediate sizes. Grid-size independence was also confirmed for a range of computational cell sizes and the calibration results for 15 standard flume sizes were compared with previously published calibration parameters. Through the validated CFD simulations, a full set of calibration and validation data was generated for each of 51 flume sizes, filling the gaps in the experimental data and permitting a full analysis of the performance of the flume. The study resulted in a generic calibration for free-flow conditions for any Cutthroat flume in the dimensional range of the 24 standard sizes and specified dimensional ratios according to the original design criteria. The error in the predicted discharge for all flume sizes is less than 3% of the full-scale discharge. DOI: 10.1061/(ASCE)HY.1943-7900.0000732. © 2013 American Society of Civil Engineers. CE Database subject headings: Flow measurement; Flumes; Canals; Calibration; Computational fluid dynamics technique. Author keywords: Flow measurement; Flumes; Cutthroat flume; Canals; Calibration.

Performance Testing Of Semi Circular Contraction Critical Flow Flumes for Field Channels

A laboratory experiment entitled Characteristics of Semi Circular Contraction Critical Flow Flumes for Low Discharges under Different Submergence Conditions was conducted in a hydraulic flume with motorized bed slope alteration facility at the Hydraulics laboratory, College of Agricultural Engineering, Bapatla, India to study the effect of percentage of contraction and submergence on flow characteristics like critical depth, location of critical depth, accuracy of measurement and total quantity of material used etc. The experiment consisted of three different contractions (20%, 40% and 60%) tested with three different discharges (10 ls -1 , 14 ls -1 and 18 ls -1 ) and four submergence levels (60%, 70%, 80% and 90%). Dimensional analyses were performed and end depth, throat width and discharge relationships were arrived. The discharges arrived conventionally based on critical depth and through equations derived through dimensional analysis were compared and presented. The deviation of discharge under free flow conditions depicted from Eq. a and Eq. b are within the range of ± 5% of actual discharge for all flumes. A single measurement of end depth in semi circular contraction critical flow flumes can be used for discharge computation in open channels, if the submergence conditions are below 80% in general. Semi circular contraction critical flow flumes can be used for discharge measurement in open channels with best accuracy of ± 5% equations developed. I. Introduction The rapidly increasing use of all available water resources and the increasing costs of on-farm irrigation development require economical use of irrigation water. Inequity in the distribution of water through the irrigation network cause lower irrigation efficiencies. To improve water management, it is strongly recommended that the irrigation water be accurately measured and regulated at all important points in an irrigation system. Cutthroat flume is one of the critical flow measuring devices for open channel flows. The flume has become popular compared to others mainly because of its simple geometry and horizontal bed, which make construction simple and reduce the cost. It is extensively used in irrigation systems in India. A circular flume is a cylinder installed axially in a prismatic channel can be used to measure discharge. However the circular flume, as presented by Hager (1985, 1986 and 1988) and Samani et al. (1991), has the disadvantage of trapping floating material, which affects reliability and function of structure. Replogle and Clemmens (1981) developed a portable flume to measure flow rates in standard concrete slip form irrigation canals. The flume resembled a broad crested weir with only two finished surfaces of long and flat weir crest and rounded approach ramp. Replogle and Clemmens (1981) reported that that critical flow flumes with contracted throat sections that are about twice as long as the maximum flow depth through the flumes produced stable and reliable calibrations accurate to ±3-5%. Samani and Megallanez (2000) developed a simple venturi flume for flow measurement in open channels. The flume was contracted using two half cylinders of PVC pipe which created a contraction. Three different half cylinders are used with 40%, 64% and 60% contractions. It has been shown that the modified cut throat can predict the measured flow rate with less than 5% error. A cost of comparison of the flume showed that it can be constructed with less than 60% cost of cutthroat flume due to lower material and labor requirements. Present research work is carried out to test the accuracy of measurement of water under different submerged conditions by preparing semi-circular contraction critical flow flumes.

Research on Hydraulic Characteristics of Cutthroat Flume in Irrigation District

In the background of the cutthroat flume of the second stem II station in the Ye River hub of Shijiazhuang, the model test is selected to analyse the hydraulic characteristics of the cutthroat flume. The results show that: (1) The influencing factors on the discharge coefficient in the calculating formula for flow deduced by theory are drawn, the discharge coefficient of the free outflow is relevant to the head above weir and the height of weir, and that of the submerged outflow has relevance to the height of weir and the upstream and downstream water level; (2) the critical condition for the submergence of cutthroat flume is determined, when the ratio of the water depth in the downstream and upstream is less than 0.76, the flow is free outflow, otherwise it is submerged outflow; (3) Based on the regression analysis, the empirical formula of discharge coefficient for the free outflow and submerged outflow are obtained, and the precision is proved to be reasonable by the error analysis.

CALIBRATION OF THREE COMMON FLOW MEASUREMENT DEVICES FOR OPEN CHANNELS

The aim of this research was to test and calibrate some water flow measurement devices, which were appropriate for on-farm management in Egypt. To fulfill this purpose, three of the common water- flow measurement devices (v-notch, rectangular weir and cutthroat flume) were calibrated in the Laboratory of Hydraulics Research Institute in Qanater City (Egypt, رطانقلا). The calibration was carried out using an ultrasonic flow- meter. Results of this study showed that under low discharges, i.e. 5 and 10 Ls -1 , the most accurate device was the v-notch, under high discharges 15, 20, 25, 30 and 35 L s -1 , the most accurate one was the rectangular weir. Increasing discharge rate from 5 to 35 L s -1 resulted in increases in error percentage in the readings of the v-notch. On the other hand, the corresponding error percentages in readings of both the rectangular weir and the cutthroat flume were obviously decreased. The decreases seemed inversely related to the increase in rate of discharge. Effect of time interval on error percentage seemed to be irregular. From the aforementioned results, it could be deduced that the v-notch weir is preferable for measuring the discharge at a rate ranging from 5 to 10 L s -1 , beyond which the rectangular weir, as well as the cutthroat flume,

Nitrate-N loadings through subsurface environment to agricultural drainage ditches in two flat Midwestern (USA) watersheds

A study was conducted to understand the contributions of tile flow and baseflow to total nitrate-N (NO 3-N) loadings in two subsurface (tile)-drained watersheds, namely the Big Ditch (BD) and the Upper Embarras River (UER) watersheds in Illinois. Two stream sections were selected in the watersheds and rectangular cutthroat flumes were installed at the upstream and downstream ends of the stream sections to calculate the flow mass balance for separating baseflow. The stream section at BD site had two tile outlets draining into it. The stream section at UER watershed did not have any tile drain. Tile flow was also measured along with stream flow. Water samples were collected not only from the stream sections using auto-samplers but also manually from the tile drains. Average baseflow rates per unit lengths of the stream sections at BD and UER sites were 3.5 × 10 −04 and 9.4 × 10 −05 m 2 s −1, respectively. At BD site, for six study periods, the percentages of baseflow and tile flow contributions of NO 3-N loads within the stream section were 90 and 10%, respectively. Annual NO 3-N contributions by the upstream subwatersheds for BD and UER stream sections were 61,819 and 16,155 kg, respectively. Annual NO 3-N loss from these two subwatersheds within BD and UER watersheds was 42.9 and 7.0 kg ha −1, respectively. For the stream section at BD site, baseflow seemed to play a more important role than tile flow in raising the NO 3-N concentration level in the stream water. Land use seemed to play a major role in the significant difference in NO 3-N concentrations at the two subwatersheds upstream from the project sites. Nitrate-N loadings primarily depended on precipitation, antecedent moisture condition (AMC), fertilizer application time, and evapotranspiration (ET).

Simulation of base-flow and tile-flow for storm events in a subsurface drained watershed

Quantifying base-flow and tile-flow to agricultural drainage ditches is essential to understand groundwater flow and nutrient dynamics in a subsurface (tile) drained watershed. This can give an insight into the contributions of different flow components to the total nutrient loads in a stream. MODFLOW (Groundwater Vistas) was used to simulate (steady-state) base-flow and tile-flow for storm events in the subsurface drained Big Ditch watershed in Champaign County, IL, USA. A stream section of approximately 200 m in an agricultural drainage ditch was selected for this study. Two tile drains were draining into the stream section from both sides (north and south banks, respectively). Two cut-throat flumes were installed at the upstream and downstream ends of the stream section to do a mass balance of flow volumes to determine base-flow. Dataloggers and stilling basins were connected to the flumes and tile drains to measure flow rates. Twelve wells were installed on both sides of the channel section to measure groundwater level for model calibration. Three storm periods were used to calibrate the model and another three storm periods to validate it. The simulated mean hydraulic conductivity of the study site was 5.52E-04 m s−1. The mean conductance values of the tile drains flowing from north and south banks were 6.39E-04 m2 s−1 and 2.71E-03 m2 s−1, respectively. The simulated flow rates were within 20% of the measured rates. It may be concluded that the model simulated base-flow and tile-flow for the storm periods successfully.