Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach

Detalhes bibliográficos
Autor(a) principal: Abrantes, João R.C.B.
Data de Publicação: 2018
Outros Autores: Moruzzi, Rodrigo B. [UNESP], Silveira, Alexandre, de Lima, João L.M.P.
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Institucional da UNESP
Texto Completo: http://dx.doi.org/10.1016/j.jhydrol.2017.12.048
http://hdl.handle.net/11449/175705
Resumo: The accurate measurement of shallow flow velocities is crucial to understand and model the dynamics of sediment and pollutant transport by overland flow. In this study, a novel triple-tracer approach was used to re-evaluate and compare the traditional and well established dye and salt tracer techniques with the more recent thermal tracer technique in estimating shallow flow velocities. For this purpose a triple tracer (i.e. dyed-salted-heated water) was used. Optical and infrared video cameras and an electrical conductivity sensor were used to detect the tracers in the flow. Leading edge and centroid velocities of the tracers were measured and the correction factors used to determine the actual mean flow velocities from tracer measured velocities were compared and investigated. Experiments were carried out for different flow discharges (32–1813 ml s−1) on smooth acrylic, sand, stones and synthetic grass bed surfaces with 0.8, 4.4 and 13.2% slopes. The results showed that thermal tracers can be used to estimate shallow flow velocities, since the three techniques yielded very similar results without significant differences between them. The main advantages of the thermal tracer were that the movement of the tracer along the measuring section was more easily visible than it was in the real image videos and that it was possible to measure space-averaged flow velocities instead of only one velocity value, with the salt tracer. The correction factors used to determine the actual mean velocity of overland flow varied directly with Reynolds and Froude numbers, flow velocity and slope and inversely with flow depth and bed roughness. In shallow flows, velocity estimation using tracers entails considerable uncertainty and caution must be taken with these measurements, especially in field studies where these variables vary appreciably in space and time.
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spelling Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approachCorrection factorDye tracerFlow velocityLaboratory experimentSalt tracerThermal tracerThe accurate measurement of shallow flow velocities is crucial to understand and model the dynamics of sediment and pollutant transport by overland flow. In this study, a novel triple-tracer approach was used to re-evaluate and compare the traditional and well established dye and salt tracer techniques with the more recent thermal tracer technique in estimating shallow flow velocities. For this purpose a triple tracer (i.e. dyed-salted-heated water) was used. Optical and infrared video cameras and an electrical conductivity sensor were used to detect the tracers in the flow. Leading edge and centroid velocities of the tracers were measured and the correction factors used to determine the actual mean flow velocities from tracer measured velocities were compared and investigated. Experiments were carried out for different flow discharges (32–1813 ml s−1) on smooth acrylic, sand, stones and synthetic grass bed surfaces with 0.8, 4.4 and 13.2% slopes. The results showed that thermal tracers can be used to estimate shallow flow velocities, since the three techniques yielded very similar results without significant differences between them. The main advantages of the thermal tracer were that the movement of the tracer along the measuring section was more easily visible than it was in the real image videos and that it was possible to measure space-averaged flow velocities instead of only one velocity value, with the salt tracer. The correction factors used to determine the actual mean velocity of overland flow varied directly with Reynolds and Froude numbers, flow velocity and slope and inversely with flow depth and bed roughness. In shallow flows, velocity estimation using tracers entails considerable uncertainty and caution must be taken with these measurements, especially in field studies where these variables vary appreciably in space and time.MARE – Marine and Environmental Sciences CentreDepartment of Civil Engineering Faculty of Sciences and Technology University of CoimbraGeoprocessing and Territorial Planning Department Geosciences and Mathematics Institute UNESP – Univ Estadual PaulistaInstitute of Science and Technology Federal University of AlfenasGeoprocessing and Territorial Planning Department Geosciences and Mathematics Institute UNESP – Univ Estadual PaulistaMARE – Marine and Environmental Sciences CentreUniversity of CoimbraUniversidade Estadual Paulista (Unesp)Federal University of AlfenasAbrantes, João R.C.B.Moruzzi, Rodrigo B. [UNESP]Silveira, Alexandrede Lima, João L.M.P.2018-12-11T17:17:09Z2018-12-11T17:17:09Z2018-02-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/article362-377application/pdfhttp://dx.doi.org/10.1016/j.jhydrol.2017.12.048Journal of Hydrology, v. 557, p. 362-377.0022-1694http://hdl.handle.net/11449/17570510.1016/j.jhydrol.2017.12.0482-s2.0-850397595532-s2.0-85039759553.pdfScopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengJournal of Hydrology1,832info:eu-repo/semantics/openAccess2023-11-13T06:09:39Zoai:repositorio.unesp.br:11449/175705Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T17:32:55.624460Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false
dc.title.none.fl_str_mv Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach
title Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach
spellingShingle Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach
Abrantes, João R.C.B.
Correction factor
Dye tracer
Flow velocity
Laboratory experiment
Salt tracer
Thermal tracer
title_short Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach
title_full Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach
title_fullStr Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach
title_full_unstemmed Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach
title_sort Comparison of thermal, salt and dye tracing to estimate shallow flow velocities: Novel triple-tracer approach
author Abrantes, João R.C.B.
author_facet Abrantes, João R.C.B.
Moruzzi, Rodrigo B. [UNESP]
Silveira, Alexandre
de Lima, João L.M.P.
author_role author
author2 Moruzzi, Rodrigo B. [UNESP]
Silveira, Alexandre
de Lima, João L.M.P.
author2_role author
author
author
dc.contributor.none.fl_str_mv MARE – Marine and Environmental Sciences Centre
University of Coimbra
Universidade Estadual Paulista (Unesp)
Federal University of Alfenas
dc.contributor.author.fl_str_mv Abrantes, João R.C.B.
Moruzzi, Rodrigo B. [UNESP]
Silveira, Alexandre
de Lima, João L.M.P.
dc.subject.por.fl_str_mv Correction factor
Dye tracer
Flow velocity
Laboratory experiment
Salt tracer
Thermal tracer
topic Correction factor
Dye tracer
Flow velocity
Laboratory experiment
Salt tracer
Thermal tracer
description The accurate measurement of shallow flow velocities is crucial to understand and model the dynamics of sediment and pollutant transport by overland flow. In this study, a novel triple-tracer approach was used to re-evaluate and compare the traditional and well established dye and salt tracer techniques with the more recent thermal tracer technique in estimating shallow flow velocities. For this purpose a triple tracer (i.e. dyed-salted-heated water) was used. Optical and infrared video cameras and an electrical conductivity sensor were used to detect the tracers in the flow. Leading edge and centroid velocities of the tracers were measured and the correction factors used to determine the actual mean flow velocities from tracer measured velocities were compared and investigated. Experiments were carried out for different flow discharges (32–1813 ml s−1) on smooth acrylic, sand, stones and synthetic grass bed surfaces with 0.8, 4.4 and 13.2% slopes. The results showed that thermal tracers can be used to estimate shallow flow velocities, since the three techniques yielded very similar results without significant differences between them. The main advantages of the thermal tracer were that the movement of the tracer along the measuring section was more easily visible than it was in the real image videos and that it was possible to measure space-averaged flow velocities instead of only one velocity value, with the salt tracer. The correction factors used to determine the actual mean velocity of overland flow varied directly with Reynolds and Froude numbers, flow velocity and slope and inversely with flow depth and bed roughness. In shallow flows, velocity estimation using tracers entails considerable uncertainty and caution must be taken with these measurements, especially in field studies where these variables vary appreciably in space and time.
publishDate 2018
dc.date.none.fl_str_mv 2018-12-11T17:17:09Z
2018-12-11T17:17:09Z
2018-02-01
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://dx.doi.org/10.1016/j.jhydrol.2017.12.048
Journal of Hydrology, v. 557, p. 362-377.
0022-1694
http://hdl.handle.net/11449/175705
10.1016/j.jhydrol.2017.12.048
2-s2.0-85039759553
2-s2.0-85039759553.pdf
url http://dx.doi.org/10.1016/j.jhydrol.2017.12.048
http://hdl.handle.net/11449/175705
identifier_str_mv Journal of Hydrology, v. 557, p. 362-377.
0022-1694
10.1016/j.jhydrol.2017.12.048
2-s2.0-85039759553
2-s2.0-85039759553.pdf
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv Journal of Hydrology
1,832
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv 362-377
application/pdf
dc.source.none.fl_str_mv Scopus
reponame:Repositório Institucional da UNESP
instname:Universidade Estadual Paulista (UNESP)
instacron:UNESP
instname_str Universidade Estadual Paulista (UNESP)
instacron_str UNESP
institution UNESP
reponame_str Repositório Institucional da UNESP
collection Repositório Institucional da UNESP
repository.name.fl_str_mv Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)
repository.mail.fl_str_mv
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