Numerical and Experimental Study of Flow in Open Channels with Cylindrical Roughness

Detalhes bibliográficos
Autor(a) principal: Zehsaz, Soheil
Data de Publicação: 2016
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10316/89120
Resumo: Documentos apresentados no âmbito do reconhecimento de graus e diplomas estrangeiros
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spelling Numerical and Experimental Study of Flow in Open Channels with Cylindrical RoughnessRoughness function ΔU+Cylindrical rib RoughnessTurbulenceVelocity profileDocumentos apresentados no âmbito do reconhecimento de graus e diplomas estrangeirosIn this study effect of the different types of surface roughness on a turbulent boundary layer was studied using 1D velocity measurements in a relatively high Reynolds free-Surface water channel. The roughness consisted cylindrical ribs with several P/D (P is the roughness spacing, D is the roughness height). The roughness elements were aligned in a direction transverse to the flow. The experiments involve one-dimensional flow velocity, water surface profiles and bed pressures and forces with different Reynolds numbers. A series of 12 tests of fully rough turbulent subcritical flow over two dimensional transverse repeated cylindrical ribs was undertaken in which the ribs were varied to give uniform rib spacing-toheight ratios of P/D = 5-20. The results show that the normalized velocity U+ for all the surfaces has significantly decreased comparing to smooth bed. The average values of the drag Cf and friction Ft coefficients are reduced with increasing of roughness distances on rough beds, also the amount of the drag and friction coefficients are the highest values on the cylindrical roughness with P/D= 15, H= 8 cm, D= 6 mm. Flow development in an openchannel with rough beds was investigated using FLUENT. The RNG k-ε turbulence model was used for subcritical flow cases. The volume of fluid (VOF) method was used to allow the free-surface to deform freely with the underlying turbulence. The main purpose of this study is to examine the effects of surface roughness on a turbulent boundary layer in a relatively different Reynolds numbers. The determination of velocity profile in turbulent open channels with rough bed is a difficult task due to the significant effects of the roughness. The velocity distributions in the log-region for the rough wall were determined and the roughness function U+, was evaluated compared to the smooth bed. The results show that the mean profiles of all the surfaces collapse well in the velocity defect form.2016-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesishttp://hdl.handle.net/10316/89120http://hdl.handle.net/10316/89120engZehsaz, Soheilinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2022-01-20T17:48:56Zoai:estudogeral.uc.pt:10316/89120Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T21:09:32.544465Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Numerical and Experimental Study of Flow in Open Channels with Cylindrical Roughness
title Numerical and Experimental Study of Flow in Open Channels with Cylindrical Roughness
spellingShingle Numerical and Experimental Study of Flow in Open Channels with Cylindrical Roughness
Zehsaz, Soheil
Roughness function ΔU+
Cylindrical rib Roughness
Turbulence
Velocity profile
title_short Numerical and Experimental Study of Flow in Open Channels with Cylindrical Roughness
title_full Numerical and Experimental Study of Flow in Open Channels with Cylindrical Roughness
title_fullStr Numerical and Experimental Study of Flow in Open Channels with Cylindrical Roughness
title_full_unstemmed Numerical and Experimental Study of Flow in Open Channels with Cylindrical Roughness
title_sort Numerical and Experimental Study of Flow in Open Channels with Cylindrical Roughness
author Zehsaz, Soheil
author_facet Zehsaz, Soheil
author_role author
dc.contributor.author.fl_str_mv Zehsaz, Soheil
dc.subject.por.fl_str_mv Roughness function ΔU+
Cylindrical rib Roughness
Turbulence
Velocity profile
topic Roughness function ΔU+
Cylindrical rib Roughness
Turbulence
Velocity profile
description Documentos apresentados no âmbito do reconhecimento de graus e diplomas estrangeiros
publishDate 2016
dc.date.none.fl_str_mv 2016-01
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10316/89120
http://hdl.handle.net/10316/89120
url http://hdl.handle.net/10316/89120
dc.language.iso.fl_str_mv eng
language eng
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instacron:RCAAP
instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
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reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
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repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
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