Application of Acoustic Doppler Velocimeters for Streamflow Measurements

Rehmel, Michael S.

doi:10.1061/(asce)0733-9429(2007)133:12(1433)

Cited by 41 publications

(31 citation statements)

References 9 publications

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“…The key aspect limiting the reliable use of the data from an automatic sensor network is the proper calibration of the rating curves, which remains an element largely dependent on the design and quality of the field measurements [42]. Most of the devices applied for the automated monitoring of the runoff are based on the monitoring of the water levels and thus require the development of rating curves based on direct discharge measurements [43]. Building a reliable database is, however, a time-consuming process, particularly when covering extreme values-both on the sides of low flows and peak flows.…”

Section: Discussionmentioning

confidence: 99%

Building a High-Precision 2D Hydrodynamic Flood Model Using UAV Photogrammetry and Sensor Network Monitoring

Langhammer

Bernsteinová²,

Miřijovský

2017

Water

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This paper explores the potential of the joint application of unmanned aerial vehicle (UAV)-based photogrammetry and an automated sensor network for building a hydrodynamic flood model of a montane stream. UAV-based imagery was used for three-dimensional (3D) photogrammetric reconstruction of the stream channel, achieving a resolution of 1.5 cm/pixel. Automated ultrasonic water level gauges, operating with a 10 min interval, were used as a source of hydrological data for the model calibration, and the MIKE 21 hydrodynamic model was used for building the flood model. Three different horizontal schematizations of the channel-an orthogonal grid, curvilinear grid, and flexible mesh-were used to evaluate the effect of spatial discretization on the results. The research was performed on Javori Brook, a montane stream in the Sumava (Bohemian Forest) Mountains, Czech Republic, Central Europe, featuring a fast runoff response to precipitation events and that is located in a core zone of frequent flooding. The studied catchments have been, since 2007, equipped with automated water level gauges and, since 2013, under repeated UAV monitoring. The study revealed the high potential of these data sources for applications in hydrodynamic modeling. In addition to the ultra-high levels of spatial and temporal resolution, the major contribution is in the method's high operability, enabling the building of highly detailed flood models even in remote areas lacking conventional monitoring. The testing of the data sources and model setup indicated the limitations of the UAV reconstruction of the stream bathymetry, which was completed by the geodetic-grade global navigation satellite system (GNSS) measurements. The testing of the different model domain schematizations did not indicate the substantial differences that are typical for conventional low-resolution data, proving the high reliability of the tested modeling workflow.

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Section: Discussionmentioning

confidence: 99%

Building a High-Precision 2D Hydrodynamic Flood Model Using UAV Photogrammetry and Sensor Network Monitoring

Langhammer

Bernsteinová²,

Miřijovský

2017

Water

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“…Both these parameters were provided in the equipment. SNR is a measure of the strength of the reflected acoustic signal relative to the ambient noise level (REHMEL, 2007). It should be higher than 10 dB to obtain consistent estimates (SONTEK; YSI INCORPORATED, 2007).…”

Section: Adv Velocity Measurementsmentioning

confidence: 99%

“…It also is affected by the inherent limitations of the Doppler Effect. The quality of the measurements depends on the presence of particles suspended in the flow, and it can be affected by the interference caused by acoustic boundaries (REHMEL, 2007).…”

Section: Introductionmentioning

confidence: 99%

An alternative method for measuring velocities in open-channel flows: perfomance evaluation of a Pitot tube compared to an acoustic meter

Almeida

Souza

2017

RBRH

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Hydrometric measurements undertaken in channels with high velocities are conditioned to the particularities of the flow, which is often characterized by instantaneous fluctuations and disturbances on the free surface. In such cases, the uncertainties associated with velocity fluctuations exceed the precision offered by the instruments that are employed in conventional techniques. A reasonable accuracy of the results is therefore sufficient to accomplish the objective of the measurements. The use of devices based on Pitot's principle in fast open-channel flows could be an effective alternative to conventional velocity meters. This study aimed to develop a Pitot tube in its simplest configuration and evaluate its performance in a laboratory channel at velocities ranging from 0.2 to 2.0 m/s. The uncertainties in the static and total head readings were propagated to the output velocities, showing that the device built has the potential for measurements over 1.2 m/s, but it is not recommended for low velocities (<0.6 m/s). The results were compared to those taken using an Acoustic Doppler Velocimeter (ADV). The instantaneous velocity readings indicated uncertainties of the same order of magnitude in both instruments. The differences between the mean velocities measured by the Pitot tube and the ADV were restricted to an agreement range of 15%, which is expected to be gradually reduced with further increase in flow velocity. The results showed the similar performances of both devices regarding the higher velocity estimates. Therefore, velocity meters should be developed to employ Pitot devices as an alternative method in high-velocity open-channel flows.Keywords: Hydrometry; Open channel flow; Differential head meters; Pitot tube. RESUMOAplicações de hidrometria em canais com altas velocidades estão sujeitas às condições do fluxo, que geralmente é caracterizado por flutuações instantâneas e perturbações na superfície livre. Nesses casos, as incertezas associadas às flutuações de velocidade superam a precisão oferecida pelos instrumentos empregados nas técnicas convencionais. Uma exatidão razoável dos resultados é, portanto, suficiente para atender ao objetivo das medições. O uso de dispositivos baseados no princípio de Pitot em escoamentos rápidos pode ser uma alternativa eficaz ao uso dos medidores de velocidade convencionais. Este estudo teve por objetivo confeccionar um tubo de Pitot em sua configuração mais simples e avaliar seu desempenho em um canal experimental para velocidades variando no intervalo de 0,2 a 2,0 m/s. As incertezas nas leituras de carga estática e de carga total foram propagadas para as velocidades estimadas, mostrando que o dispositivo construído tem potencial para medições acima de 1,2 m/s, mas não é recomendado para baixas velocidades (<0,6 m/s). Os resultados foram comparados com um Velocímetro Acústico de Efeito Doppler (ADV). As leituras de velocidade instantânea indicaram incertezas de mesma magnitude em ambos os instrumentos. As diferenças entre as velocidades médias estimadas co...

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“…The use of the UDFM requires the presence of sonically reflective materials such as solid particles (or entrained air bubbles) in the liquid flowing through the pipe: indeed the performance of the flow meter is tied to the particle density and particle concentration and distribution in the measurement section, as well as to the temperature and the sonic conductivity of the liquid. The use of an UDFM, therefore, is based on the fundamental hypothesis that the particles are moving at the same velocity as the fluid [20][21][22]. The principles of acoustic measurement with Doppler flow meters are mathematically expressed by the eqn.…”

Section: Principles Of Ultrasonic Velocimetrymentioning

confidence: 99%

Experimental tests on ultrasonic flow meter performance in full-flowing pipes

Ciaravino

2011

Surface Effects and Contact Mechanics X

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Tests based on non destructive techniques are fundamental for measurements on fully operational plants. This work details the results obtained in experimental tests on full-flowing pipes made of a variety of materials highlighting some of the characteristics and limitations in the performance of the ultrasonic flow meter which must be taken into account. The research carried out using a Doppler ultrasonic flow meter (UDFM) illustrated anomalies in the device's function on steel pipes that have been in service for many years and in which significant internal irregularities and incrustations were present. With the internal surface of the pipe wall in such conditions, the acoustic signal loses its coherence, in passing through the pipe wall twice, thus making its detection difficult for the receiver. Further tests conducted on acrylic pipes, characterized by an extremely smooth internal surface and under the same experimental conditions, did not present the running anomalies encountered in the old steel pipes.

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Application of Acoustic Doppler Velocimeters for Streamflow Measurements

Cited by 41 publications

References 9 publications

Building a High-Precision 2D Hydrodynamic Flood Model Using UAV Photogrammetry and Sensor Network Monitoring

Building a High-Precision 2D Hydrodynamic Flood Model Using UAV Photogrammetry and Sensor Network Monitoring

An alternative method for measuring velocities in open-channel flows: perfomance evaluation of a Pitot tube compared to an acoustic meter

Experimental tests on ultrasonic flow meter performance in full-flowing pipes

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