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

Almeida, Arlan Scortegagna; Souza, Vladimir Caramori Borges de

doi:10.1590/2318-0331.011716099

Cited by 4 publications

(3 citation statements)

References 17 publications

(14 reference statements)

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“…Bernoulli run-up is also referred to as the "velocity head rod" by Church and Kellerhals (1970), Carufel (1980), and Fonstad et al (2005) and is similar to the "weir stick" discussed by USBR (2001). The velocity measurement theory of Bernoulli is similar to using a pitot tube (Almeida and de Souza, 2017), without the associated challenges of (1) using and transporting potentially bulky and fragile equipment and (2) clogging from sediment or trash (WMO, 2010). However, the accuracy and precision of the Bernoulli method velocity head measurements are likely lower than pitot measurements.…”

Section: Bernoulli Run-up Methodsmentioning

confidence: 99%

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Citizen science flow – an assessment of simple streamflow measurement methods

Davids

Rutten

Pandey³

et al. 2019

Hydrol. Earth Syst. Sci.

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Abstract. Wise management of water resources requires data. Nevertheless, the amount of streamflow data being collected globally continues to decline. Generating hydrologic data together with citizen scientists can help fill this growing hydrological data gap. Our aim herein was to (1) perform an initial evaluation of three simple streamflow measurement methods (i.e., float, salt dilution, and Bernoulli run-up), (2) evaluate the same three methods with citizen scientists, and (3) apply the preferred method at more sites with more people. For computing errors, we used midsection measurements from an acoustic Doppler velocimeter as reference flows. First, we (authors) performed 20 evaluation measurements in headwater catchments of the Kathmandu Valley, Nepal. Reference flows ranged from 6.4 to 240 L s−1. Absolute errors averaged 23 %, 15 %, and 37 % with average biases of 8 %, 6 %, and 26 % for float, salt dilution, and Bernoulli methods, respectively. Second, we evaluated the same three methods at 15 sites in two watersheds within the Kathmandu Valley with 10 groups of citizen scientists (three to four members each) and one “expert” group (authors). At each site, each group performed three simple methods; experts also performed SonTek FlowTracker midsection reference measurements (ranging from 4.2 to 896 L s−1). For float, salt dilution, and Bernoulli methods, absolute errors averaged 41 %, 21 %, and 43 % for experts and 63 %, 28 %, and 131 % for citizen scientists, while biases averaged 41 %, 19 %, and 40 % for experts and 52 %, 7 %, and 127 % for citizen scientists, respectively. Based on these results, we selected salt dilution as the preferred method. Finally, we performed larger-scale pilot testing in week-long pre- and post-monsoon Citizen Science Flow campaigns involving 25 and 37 citizen scientists, respectively. Observed flows (n=131 pre-monsoon; n=133 post-monsoon) were distributed among the 10 headwater catchments of the Kathmandu Valley and ranged from 0.4 to 425 L s−1 and from 1.1 to 1804 L s−1 in pre- and post-monsoon, respectively. Future work should further evaluate uncertainties of citizen science salt dilution measurements, the feasibility of their application to larger regions, and the information content of additional streamflow data.

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Section: Bernoulli Run-up Methodsmentioning

confidence: 99%

“…2.2. The theoretical training also introduced citizen scientists to Open Data Kit (ODK; Anokwa et al, 2009), a freely available open-source software for collecting and managing data in low-resource settings. ODK was used with the specific streamflow measurement workflow described below.…”

Section: Citizen Scientist Evaluation (Phase 2)mentioning

confidence: 99%

Citizen science flow – an assessment of simple streamflow measurement methods

Davids

Rutten

Pandey³

et al. 2019

Hydrol. Earth Syst. Sci.

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“…The bath stirring rate was varied from 200 rpm to 1000 rpm with an interval of 200 rpm, and the corresponding rise in the electrolyte level within the Pitot tube’s column (i.e.,

was recorded five times for each bath stirring rate. Subsequently,

was calculated using Equation (3) by considering

as 1 [ 36 ], and plotted as a function of bath stirring rate as shown in Figure 2 b, where the bath stirring rate from 200 rpm to 1000 rpm resulted in

(at 4 cm from the vortex center) from 8 cm/s to 42 cm/s, respectively. A good agreement is found between the simulated vortex velocity and the measured vortex velocity from the vortex core ( Figure 2 b).…”

Section: Modelling Of Electrolyte Vortex Flow Created By Magnetic Stirring and Determination Of Optimum Electrode Position Within The Vormentioning

confidence: 99%

Influence of Bath Hydrodynamics on the Micromechanical Properties of Electrodeposited Nickel-Cobalt Alloys

2021

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The influence of bath hydrodynamics on the resultant micromechanical properties of electrodeposited nickel-cobalt alloy system is investigated. The bath hydrodynamics realized by magnetic stirring is simulated using COMSOL Multiphysics and a region of minimum variation in velocity within the electrolytic cell is determined and validated experimentally. Nickel-cobalt alloy and nickel coating samples are deposited galvanostatically (50 mA/cm2) with varying bath velocity (0 to 42 cm/s). The surface morphology of samples gradually changed from granular (fractal dimension 2.97) to more planar (fractal dimension 2.15) growth type, and the according average roughness decreased from 207.5 nm to 11 nm on increasing the electrolyte velocity from 0 to 42 cm/s for nickel-cobalt alloys; a similar trend was also found in the case of nickel coatings. The calculated grain size from the X-ray diffractograms decreased from 31 nm to 12 nm and from 69 nm to 26 nm as function of increasing velocity (up to 42 cm/s) for nickel-cobalt and nickel coatings, respectively. Consecutively, the measured Vickers microhardness values increased by 43% (i.e., from 393 HV0.01 to 692 HV0.01) and by 33% (i.e., from 255 HV0.01 to 381 HV0.01) for nickel-cobalt and nickel coatings, respectively, which fits well with the Hall–Petch relation.

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