scholarly journals Investigation of ultrasonic flowmeter error in distorted flow using two-peak Salami functions

2021 ◽  
Vol 7 (2) ◽  
pp. 144-151
Author(s):  
Fedir Matiko ◽  
◽  
Vitalii Roman ◽  
Halyna Matiko ◽  
Dmytro Yalinskyi
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Cross Section ◽  
Ultrasonic Flowmeter ◽  
Additional Error ◽  
Average Flow ◽  
Research Results ◽  
Pipe Cross Section ◽  
Average Flow Velocity ◽  
Flow Velocity Profile

Results of investigating the additional error of ultrasonic flowmeters caused by the distortion of the flow are presented in the article. The location coordinates of acoustic paths were calculated for their number from 1 to 6 according to the different numerical integrating methods: Gauss (Gauss-Legendre, Gauss-Jacobi), Chebyshev (equidistant location of acoustic paths), Westinghouse method, method of OWICS (Optimal Weighted Integration for Circular Sections). This made it possible to realize the flowrate equation for multi-path ultrasonic flowmeters and to determine their additional error for different location of the acoustic paths. The average flow velocity along each path is calculated based on the flow velocity profile in the pipe cross section. Four two-peak Salami functions of velocity are used to calculate the velocity profile of the distorted flow caused by typical local resistances. According to the research results the recommendations were developed for choosing the number of the acoustic paths of the ultrasonic flowmeters and for using the methods for determining the location coordinates of the acoustic paths.

scholarly journals Investigating the Ultrasonic Flowmeter Error in Conditions of Distorted Flow Using Multipeaks Salami Functions

2019 ◽  
pp. 14-19
Author(s):  
Ye. Pistun ◽  
V. Roman ◽  
F. Matiko
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
High Sensitivity ◽  
Calibration Factor ◽  
Ultrasonic Flowmeter ◽  
Additional Error ◽  
Complex Flow ◽  
Average Flow Velocity ◽  
Minimum Number ◽  
Flow Velocity Profile

Paper is devoted to the problem of improving the accuracy of ultrasonic flowmeters installed in conditions that differ from their calibration conditions. The authors highlighted high sensitivity of ultrasonic flowmeters to distortions of flow structure and large additional error of flowmeters caused by flow distortions. The computer simulations using empirically-derived functions of distorted flow velocity of professor Salami are used to investigate the additional error of flowmeters. The analytical formulas of two- and multi-peaks Salami functions are used in this work to reproduce the distorted flow velocity profile. The authors proposed to determine the calibration factor of the ultrasonic flowmeter using the undistorted component of Salami functions. The values of the calibration factor for the number of acoustic channels from 1 to 6 were calculated using four numerical integration methods: Chebyshev (equidistant location of acoustic paths), Gauss, Gauss-Jacobi, OWICS met­hod. This made it possible to realize the flowrate equation for multi-path ultrasonic flowmeters and to determine their additional error for different location of the acoustic paths. The average flow velocity along each path is calculated based on the flow velocity profile in the pipe cross section. Six two- and multi-peaks Salami functions of velocity are used to calculate the velocity profile of the distorted flow caused by typical local resistances. According to the research results the recommendations were developed for choosing the number of the acoustic paths of the ultrasonic flowmeters and for using the methods for determining the location coordinates of the acoustic paths. We determined the required minimum number of chordal acoustic channels of the ultrasonic flowmeter, which makes it possible to reduce the investigated error to defined limits, even in the presence of complex flow distortions reproduced by Salami multi-peaks functions.

scholarly journals Optimized Vegetation Density to Dissipate Energy of Flood Flow in Open Canals

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Mahdi Feizbahr ◽  
Navid Tonekaboni ◽  
Guang-Jun Jiang ◽  
Hong-Xia Chen
Keyword(s):  
Flow Velocity ◽  
Cross Section ◽  
Flow Resistance ◽  
Vegetation Density ◽  
Flow Conditions ◽  
Average Flow ◽  
Flow Energy ◽  
Average Flow Velocity ◽  
Flow Velocity Profile ◽  
Flood Flow

Vegetation along the river increases the roughness and reduces the average flow velocity, reduces flow energy, and changes the flow velocity profile in the cross section of the river. Many canals and rivers in nature are covered with vegetation during the floods. Canal’s roughness is strongly affected by plants and therefore it has a great effect on flow resistance during flood. Roughness resistance against the flow due to the plants depends on the flow conditions and plant, so the model should simulate the current velocity by considering the effects of velocity, depth of flow, and type of vegetation along the canal. Total of 48 models have been simulated to investigate the effect of roughness in the canal. The results indicated that, by enhancing the velocity, the effect of vegetation in decreasing the bed velocity is negligible, while when the current has lower speed, the effect of vegetation on decreasing the bed velocity is obviously considerable.

Experimental Investigation of Mean Flow Profile Effects on Impedance Eduction

2021 ◽  
Vol 263 (1) ◽  
pp. 5858-5868
Author(s):  
Victor Kopiev ◽  
NIkolay Ostrikov ◽  
Stanislav Denisov ◽  
MIkhail Yakovets ◽  
Maxim Ipatov
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Cross Section ◽  
Three Dimensional ◽  
Descent Method ◽  
Gradient Descent Method ◽  
Flow Profile ◽  
Mean Flow ◽  
Flow Velocity Profile ◽  
Made In

The results of experimental and computational studies of the three-dimensional mean flow velocity profile influence on the impedance eduction are presented. In order to measure the three-dimensional velocity profile, the TsAGIâ€(tm)s “Interferometer with flow†facility was upgraded so that additional holes were made in one cross section of the rectangular duct. As a result, it became possible to measure the longitudinal flow velocity in this cross section along 6 lines using a Pitot tube or a hot wire anemometer. The full three-dimensional velocity profile is determined by interpolating the values measured.Experimental results of the velocity profile for various experiment conditions are presented. Based on the numerical solution of the three-dimensional Pridmore-Brown equation by means of Finite Element Method and the gradient descent method, the problem of impedance eduction are investigated. The influence of the flow velocity profile and the form of functional on the obtained impedance values are discussed. The impedance values educted by means of this approach are compared with the impedance values obtained using two-dimensional impedance eduction methods, which didnâ€(tm)t taking into account the three-dimensional non homogeneity of the flow velocity field.

Investigation of the influence of the flow structure on the accuracy of flow measurement before a hydrometric structure in an open channel

2020 ◽  
pp. 41-44
Author(s):  
Anatoly Kusher
Keyword(s):  
Velocity Profile ◽  
Flow Velocity ◽  
Water Flow ◽  
Flow Measurement ◽  
Water Discharge ◽  
Critical Depth ◽  
Flow Measurements ◽  
Study Results ◽  
Flow Velocity Profile ◽  
Upstream Flow

The reliability of water flow measurement in irrigational canals depends on the measurement method and design features of the flow-measuring structure and the upstream flow velocity profile. The flow velocity profile is a function of the channel geometry and wall roughness. The article presents the study results of the influence of the upstream flow velocity profile on the discharge measurement accuracy. For this, the physical and numerical modeling of two structures was carried out: a critical depth flume and a hydrometric overfall in a rectangular channel. According to the data of numerical simulation of the critical depth flume with a uniform and parabolic (1/7) velocity profile in the upstream channel, the values of water discharge differ very little from the experimental values in the laboratory model with a similar geometry (δ < 2 %). In contrast to the critical depth flume, a change in the velocity profile only due to an increase in the height of the bottom roughness by 3 mm causes a decrease of the overfall discharge coefficient by 4…5 %. According to the results of the numerical and physical modeling, it was found that an increase of backwater by hydrometric structure reduces the influence of the upstream flow velocity profile and increases the reliability of water flow measurements.

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