Development of procedures for the simulation of atmospheric flows over complex terrain, using OpenFOAM
Autor(a) principal: | |
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Data de Publicação: | 2013 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.22/4691 |
Resumo: | The main purpose of this work was the development of procedures for the simulation of atmospheric ows over complex terrain, using OpenFOAM. For this aim, tools and procedures were developed apart from this code for the preprocessing and data extraction, which were thereafter applied in the simulation of a real case. For the generation of the computational domain, a systematic method able to translate the terrain elevation model to a native OpenFOAM format (blockMeshDict) was developed. The outcome was a structured mesh, in which the user has the ability to de ne the number of control volumes and its dimensions. With this procedure, the di culties of case set up and the high computation computational e ort reported in literature associated to the use of snappyHexMesh, the OpenFOAM resource explored until then for the accomplishment of this task, were considered to be overwhelmed. Developed procedures for the generation of boundary conditions allowed for the automatic creation of idealized inlet vertical pro les, de nition of wall functions boundary conditions and the calculation of internal eld rst guesses for the iterative solution process, having as input experimental data supplied by the user. The applicability of the generated boundary conditions was limited to the simulation of turbulent, steady-state, incompressible and neutrally strati ed atmospheric ows, always recurring to RaNS (Reynolds-averaged Navier-Stokes) models. For the modelling of terrain roughness, the developed procedure allowed to the user the de nition of idealized conditions, like an uniform aerodynamic roughness length or making its value variable as a function of topography characteristic values, or the using of real site data, and it was complemented by the development of techniques for the visual inspection of generated roughness maps. The absence and the non inclusion of a forest canopy model limited the applicability of this procedure to low aerodynamic roughness lengths. The developed tools and procedures were then applied in the simulation of a neutrally strati ed atmospheric ow over the Askervein hill. In the performed simulations was evaluated the solution sensibility to di erent convection schemes, mesh dimensions, ground roughness and formulations of the k - ε and k - ω models. When compared to experimental data, calculated values showed a good agreement of speed-up in hill top and lee side, with a relative error of less than 10% at a height of 10 m above ground level. Turbulent kinetic energy was considered to be well simulated in the hill windward and hill top, and grossly predicted in the lee side, where a zone of ow separation was also identi ed. Despite the need of more work to evaluate the importance of the downstream recirculation zone in the quality of gathered results, the agreement between the calculated and experimental values and the OpenFOAM sensibility to the tested parameters were considered to be generally in line with the simulations presented in the reviewed bibliographic sources. |
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Development of procedures for the simulation of atmospheric flows over complex terrain, using OpenFOAMComputational fluid dynamicsCFDSimulation of atmospheric flows over complex terrainOpenFOAMMecânica dos fluídos computacionalSimulação de escoamentos atmosféricos sobre topografia complexaThe main purpose of this work was the development of procedures for the simulation of atmospheric ows over complex terrain, using OpenFOAM. For this aim, tools and procedures were developed apart from this code for the preprocessing and data extraction, which were thereafter applied in the simulation of a real case. For the generation of the computational domain, a systematic method able to translate the terrain elevation model to a native OpenFOAM format (blockMeshDict) was developed. The outcome was a structured mesh, in which the user has the ability to de ne the number of control volumes and its dimensions. With this procedure, the di culties of case set up and the high computation computational e ort reported in literature associated to the use of snappyHexMesh, the OpenFOAM resource explored until then for the accomplishment of this task, were considered to be overwhelmed. Developed procedures for the generation of boundary conditions allowed for the automatic creation of idealized inlet vertical pro les, de nition of wall functions boundary conditions and the calculation of internal eld rst guesses for the iterative solution process, having as input experimental data supplied by the user. The applicability of the generated boundary conditions was limited to the simulation of turbulent, steady-state, incompressible and neutrally strati ed atmospheric ows, always recurring to RaNS (Reynolds-averaged Navier-Stokes) models. For the modelling of terrain roughness, the developed procedure allowed to the user the de nition of idealized conditions, like an uniform aerodynamic roughness length or making its value variable as a function of topography characteristic values, or the using of real site data, and it was complemented by the development of techniques for the visual inspection of generated roughness maps. The absence and the non inclusion of a forest canopy model limited the applicability of this procedure to low aerodynamic roughness lengths. The developed tools and procedures were then applied in the simulation of a neutrally strati ed atmospheric ow over the Askervein hill. In the performed simulations was evaluated the solution sensibility to di erent convection schemes, mesh dimensions, ground roughness and formulations of the k - ε and k - ω models. When compared to experimental data, calculated values showed a good agreement of speed-up in hill top and lee side, with a relative error of less than 10% at a height of 10 m above ground level. Turbulent kinetic energy was considered to be well simulated in the hill windward and hill top, and grossly predicted in the lee side, where a zone of ow separation was also identi ed. Despite the need of more work to evaluate the importance of the downstream recirculation zone in the quality of gathered results, the agreement between the calculated and experimental values and the OpenFOAM sensibility to the tested parameters were considered to be generally in line with the simulations presented in the reviewed bibliographic sources.O presente trabalho teve como principal objetivo o desenvolvimento de procedimentos para a simulação de escoamentos atmosféricos sobre topografa complexa, usando OpenFOAM. Para este _m foram desenvolvidos procedimentos e ferramentas externas a este código, adequados ao pré-processamento e extracção de dados, os quais foram posteriormente aplicados na simulação de um caso pratico. Para a geração do domínio computacional foi criado um método sistemático capaz de traduzir o modelo de elevação da topografia em estudo para um formato nativo do OpenFOAM (blockMeshDict). O resultado foi a obtenção de uma malha estruturada, na qual o utilizador tem a possibilidade de definir o número e dimensões dos volumes de controlo. Com este procedimento foram consideradas como ultrapassadas as dificuldades de configuração e a necessidade de elevados recursos computacionais reportadas na literatura associadas à utilização da ferramenta snappyHexMesh, o recurso do OpenFOAM até aqui explorado para a realização desta tarefa. Os procedimentos desenvolvidos para geração de condições de fronteira permitiram a automatização da criação de perfis verticais de entrada idealizados, a definição das condições de parede e a determinação de valores para arranque do processo iterativo de resolução, tendo como dados de entrada valores experimentais fornecidos pelo utilizador. A aplicabilidade das condições de fronteira geradas foi limitada à simulação de escoamentos turbulentos, estacionários, incompressíveis e em regime neutralmente estratificado, sempre com o recurso a modelos RaNS (Reynolds-averaged Navier-Stokes). Para modelação da rugosidade de superfície, o procedimento desenvolvido permitiu a definição por parte do utilizador de condições idealizadas, como a definição de um valor de rugosidade uniforme ou a variação deste em função de parâmetros característicos da topografia, ou a utilização de dados reais de superfície, e foi complementado com o desenvolvimento de técnicas para a inspecção visual dos mapas de rugosidade gerados. A não abordagem neste trabalho da possibilidade de inclusão de modelos de oresta limitou a validade deste procedimento a valores de rugosidade considerados como reduzidos. Os procedimentos e ferramentas desenvolvidos foram aplicados na simulação de um escoamento atmosférico neutralmente estratificado sobre o Monte de Askervein. Nas diversas simulações realizadas foi avaliada a sensibilidade da solução a diferentes esquemas convectivos, tamanhos de malha, condições de rugosidade e formulações dos modelos de turbulência K – E e K - w. Quando comparados com dados experimentais, os valores obtidos demonstraram uma boa concordância do speed-up no topo e a jusante da topografia, obtendo-se erros inferiores a 10% a uma altitude de 10 m acima do solo. A energia cinética turbulenta foi considerada como bem simulada a montante e no topo da topografia, e prevista de forma grosseira a jusante, local onde foi também identificada uma zona de separação do escoamento. Não obstante a necessidade de mais trabalho para aferir a importância da presença de uma zona de recirculação a jusante da topografia na qualidade dos resultados, em termos gerais, a concordância da solução obtida com os valores experimentais e a sensibilidade do OpenFOAM aos diversos parâmetros testados foram consideradas como estando em linha com outras simulações presentes na literatura.Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto.Castro, Fernando AristidesCosta, José Carlos Pereira Lopes daRepositório Científico do Instituto Politécnico do PortoAzevedo, João Manuel da Silva2014-07-03T13:54:59Z20132013-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10400.22/4691TID:201813734enginfo: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:RCAAP2023-03-13T12:44:48Zoai:recipp.ipp.pt:10400.22/4691Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T17:25:33.139383Repositório 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 |
Development of procedures for the simulation of atmospheric flows over complex terrain, using OpenFOAM |
title |
Development of procedures for the simulation of atmospheric flows over complex terrain, using OpenFOAM |
spellingShingle |
Development of procedures for the simulation of atmospheric flows over complex terrain, using OpenFOAM Azevedo, João Manuel da Silva Computational fluid dynamics CFD Simulation of atmospheric flows over complex terrain OpenFOAM Mecânica dos fluídos computacional Simulação de escoamentos atmosféricos sobre topografia complexa |
title_short |
Development of procedures for the simulation of atmospheric flows over complex terrain, using OpenFOAM |
title_full |
Development of procedures for the simulation of atmospheric flows over complex terrain, using OpenFOAM |
title_fullStr |
Development of procedures for the simulation of atmospheric flows over complex terrain, using OpenFOAM |
title_full_unstemmed |
Development of procedures for the simulation of atmospheric flows over complex terrain, using OpenFOAM |
title_sort |
Development of procedures for the simulation of atmospheric flows over complex terrain, using OpenFOAM |
author |
Azevedo, João Manuel da Silva |
author_facet |
Azevedo, João Manuel da Silva |
author_role |
author |
dc.contributor.none.fl_str_mv |
Castro, Fernando Aristides Costa, José Carlos Pereira Lopes da Repositório Científico do Instituto Politécnico do Porto |
dc.contributor.author.fl_str_mv |
Azevedo, João Manuel da Silva |
dc.subject.por.fl_str_mv |
Computational fluid dynamics CFD Simulation of atmospheric flows over complex terrain OpenFOAM Mecânica dos fluídos computacional Simulação de escoamentos atmosféricos sobre topografia complexa |
topic |
Computational fluid dynamics CFD Simulation of atmospheric flows over complex terrain OpenFOAM Mecânica dos fluídos computacional Simulação de escoamentos atmosféricos sobre topografia complexa |
description |
The main purpose of this work was the development of procedures for the simulation of atmospheric ows over complex terrain, using OpenFOAM. For this aim, tools and procedures were developed apart from this code for the preprocessing and data extraction, which were thereafter applied in the simulation of a real case. For the generation of the computational domain, a systematic method able to translate the terrain elevation model to a native OpenFOAM format (blockMeshDict) was developed. The outcome was a structured mesh, in which the user has the ability to de ne the number of control volumes and its dimensions. With this procedure, the di culties of case set up and the high computation computational e ort reported in literature associated to the use of snappyHexMesh, the OpenFOAM resource explored until then for the accomplishment of this task, were considered to be overwhelmed. Developed procedures for the generation of boundary conditions allowed for the automatic creation of idealized inlet vertical pro les, de nition of wall functions boundary conditions and the calculation of internal eld rst guesses for the iterative solution process, having as input experimental data supplied by the user. The applicability of the generated boundary conditions was limited to the simulation of turbulent, steady-state, incompressible and neutrally strati ed atmospheric ows, always recurring to RaNS (Reynolds-averaged Navier-Stokes) models. For the modelling of terrain roughness, the developed procedure allowed to the user the de nition of idealized conditions, like an uniform aerodynamic roughness length or making its value variable as a function of topography characteristic values, or the using of real site data, and it was complemented by the development of techniques for the visual inspection of generated roughness maps. The absence and the non inclusion of a forest canopy model limited the applicability of this procedure to low aerodynamic roughness lengths. The developed tools and procedures were then applied in the simulation of a neutrally strati ed atmospheric ow over the Askervein hill. In the performed simulations was evaluated the solution sensibility to di erent convection schemes, mesh dimensions, ground roughness and formulations of the k - ε and k - ω models. When compared to experimental data, calculated values showed a good agreement of speed-up in hill top and lee side, with a relative error of less than 10% at a height of 10 m above ground level. Turbulent kinetic energy was considered to be well simulated in the hill windward and hill top, and grossly predicted in the lee side, where a zone of ow separation was also identi ed. Despite the need of more work to evaluate the importance of the downstream recirculation zone in the quality of gathered results, the agreement between the calculated and experimental values and the OpenFOAM sensibility to the tested parameters were considered to be generally in line with the simulations presented in the reviewed bibliographic sources. |
publishDate |
2013 |
dc.date.none.fl_str_mv |
2013 2013-01-01T00:00:00Z 2014-07-03T13:54:59Z |
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/10400.22/4691 TID:201813734 |
url |
http://hdl.handle.net/10400.22/4691 |
identifier_str_mv |
TID:201813734 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto. |
publisher.none.fl_str_mv |
Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto. |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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 |
repository.mail.fl_str_mv |
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1799131348721467392 |