Current Meter Calibration And Three-Dimensional Displacement Effects

Staubli, T.; Hegland, Markus

doi:10.1080/00221688209499473

Cited by 4 publications

(5 citation statements)

References 1 publication

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“…The testing of horizontal-axis meters to determine the effect of placing this type of meter in close proximity to boundaries has been reported on by Murphy (1902), Rumpf (1914), Rohwer (1933), Pierce (1941), Dodge (1965), Johnson (1966), and Staubli and Hegland (1982). Proximity to boundaries includes placing the meter close to side boundaries, surface boundaries, bottom boundaries, and mounting assemblies.…”

Section: Proximity To Boundariesmentioning

confidence: 99%

“…As with the tests conducted on vertical-axis meters next to boundaries, some of the tests reported in the literature are flawed because of the methods used in the testing, because of the lack of a true reference velocity, or both. The tests that do have reference velocities or pertain only to mounting assemblies are Murphy (1902), Pierce (1941), Dodge (1965), Johnson (1966), and Staubli and Hegland (1982). Murphy (1902) reports on a set of tests in which he compares the velocity measurements of a Haskell meter to that of a 6-in.…”

Section: Proximity To Boundariesmentioning

confidence: 99%

“…This test is also flawed for the same reasons stated above. Staubli and Hegland (1982) present a derivation of a theoretical equation for the determination of the effects of a meter's mount on its calibration equation. The major effect looked at during the tests was the distance the meter mount extended below the meter itself.…”

Section: Proximity To Boundariesmentioning

confidence: 99%

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Review of literature on the testing of point-velocity current meters

Thibodeaux¹

1994

Open-File Report

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Section: Proximity To Boundariesmentioning

confidence: 99%

Section: Proximity To Boundariesmentioning

confidence: 99%

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Review of literature on the testing of point-velocity current meters

Thibodeaux¹

1994

Open-File Report

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“…3) (Engel, 1999;Johnstone, 2008;Staubli & Hegland, 1982;Mattas & Ramešová, 2013). Previous studies using two linear equations for velocities higher and lower than 0.3 m s -1 , for the same current meter propellers, reported that for low velocities the linear equation is no longer adequate, and proposed an exponential model (Eq.…”

Section: Methodsmentioning

confidence: 99%

Development and evaluation of an automated system for testing current meters

Saretta

Camargo

Botrel

et al. 2016

Rev. bras. eng. agríc. ambient.

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A B S T R A C TCurrent meters are equipment widely used for estimating flow velocity in rivers and streams. Periodic calibrations of current meters are important to ensure the quality of measurements, but the required testing facilities are complex and only available in a few institutions. However, advances in electronics and automation may contribute to developing simple and reliable calibration systems. Thus, this study aimed to develop an automated system for testing current meters, which consisted of a trapezoidal channel, a step motor, a tow car and a management system, composed of a supervisory application and microprocessed modules to control the motor and the data acquisition. Evaluations of the displacement velocity showed that it matched the reference value up to 1.85 m s -1 for a vertical-axis current meter and 2.3 m s -1 for a horizontal-axis one. The developed system showed reliability during tests, for both current meter movement and data acquisition. The management of the system based on the developed modules and the supervisory application improved its user interface, turning all the procedure into a simple task.Desenvolvimento e avaliação de um sistema automatizado para ensaios de molinetes R E S U M OMolinetes são equipamentos amplamente utilizados para estimativa da velocidade da água em cursos d'água. A calibração periódica de molinetes é necessária para assegurar a qualidade das medições mesmo requerendo infraestrutura complexa para ensaios dos quais poucas instituições dispõem; contudo, os avanços em eletrônica e automação podem contribuir para desenvolver sistemas de calibração simples e confiáveis; assim, desenvolveuse um sistema automatizado para ensaios de molinetes formados por um canal trapezoidal, motor de passo, carro de reboque e um sistema de gerenciamento composto por aplicativo supervisório e módulos microprocessado para controle do motor e aquisição de dados do molinete. Avaliações da velocidade de deslocamento mostraram correspondência com valor de referência até 1,85 m s -1 para um molinete de eixo vertical e 2,3 m s -1 para um de eixo horizontal. O sistema desenvolvido apresentou confiabilidade na execução dos ensaios tanto na movimentação do molinete quanto na aquisição de dados. O gerenciamento do sistema por meio dos módulos desenvolvidos e do aplicativo supervisório facilitou sua utilização por parte do usuário tornando a rotina de calibração bastante simples.

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“…Among them, some environmental conditions can be modified. For example, Staubli [9] proposed a velocity correction method for the displacement effect in small cross-section water. Johnson [10] researched the law that water temperature affects, and Daniel [11] further proposed a current velocity calculation method with temperature correction.…”

Section: Introductionmentioning

confidence: 99%

Uncertainty Evaluation Method of Rotating Element Current Meters

Liu¹,

Hu²,

Shi³

et al. 2023

Proceedings of the 19th International Flow Measurement Conference 2022 on Flow Measurement - FLOMEKO 2022

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The main expression of the calibration results of rotating element current meter is based on the approximate linear relationship between rotation rate and velocity, and the uncertainty evaluation method is not perfect. A technical scheme with hydraulic pitch as the result of calibration is studied, and the uncertainty can be devided to standard current velocity, rotation rate and hydraulic pitch. The measurement and uncertainty evaluation method of unit velocity and background velocity are studied based on the water velocity calibration platform. The calculation method of unit rotation rate for synchronous equidistant trigger speed measurement is proposed, and the uncertainty evaluation of unit rotation rate is realized through the self-developed standard rotation rate experimental platform. The uncertainty evaluation method for the laboratory calibration and onsite measurement results of current meter is proposed, based on the analysis of the calibration results of hydraulic screw pitch and the relationship between the calibration results and environmental factors. The results show that, the uncertainty of water flow velocity standard device is 0.04%v+2mm/s, the background velocity is the main uncertainty source in laboratory calibration results. After reasonable correcting the environmental impact of positive hydraulic pitch, the change of mechanical properties caused by long-term use is the main source of uncertainty.

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Current Meter Calibration And Three-Dimensional Displacement Effects

Cited by 4 publications

References 1 publication

Review of literature on the testing of point-velocity current meters

Review of literature on the testing of point-velocity current meters

Development and evaluation of an automated system for testing current meters

Uncertainty Evaluation Method of Rotating Element Current Meters

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