Experimental Study of a Plunging NACA0012 Airfoil under Asymmetric Oscillations
Autor(a) principal: | |
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Data de Publicação: | 2023 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.6/13764 |
Resumo: | The need to overcome new challenges made the human being seek in nature ways to surpass specific problems through Biomimetics. Through the observation of locomotion modes of animals such as birds and insects, a great interest emerged in this form of motion that allows the simultaneous generation of thrust and lift at low Reynolds numbers. This dissertation has the primary objective of exploring experimentally the asymmetric movement of a NACA0012 airfoil in purely vertical motion. It is also intended to study the influence of the nondimensional amplitude and reduced frequency on the wake patterns of the airfoil. Finally, will be performed an analysis of the influence of motion asymmetry, nondimensional amplitude and reduced frequency on the airfoil’s effective angle of attack. The tests are carried out in an open-section wind tunnel using a smoke machine to mark the flow and a highspeed camera to capture the airfoil’s wake. All tests are performed with a Reynolds number of 1 × 104 and four levels of asymmetry, ? = 0.5, ? = 0.6, ? = 0.7 and ? = 0.8, are considered. The nondimensional amplitude studied is between 0.125 and 0.5, and the reduced frequency ranges between 0.5 and 8. The visualization of the flow indicates that the asymmetric motion produces both thrust and lift and that increasing the asymmetry parameter makes the vorticity more intense. Furthermore, these vortices form earlier. Nondimensional amplitude and reduced frequency have a similar impact. It is found that vortices form further upstream with the increase of these parameters, and their intensity also increases. Regarding the effective angle of attack, it is observed through the results that the rise of these three parameters causes an increase in this angle. The separation of the flow occurs earlier for higher values of the asymmetry parameter, nondimensional amplitude and reduced frequency. |
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Experimental Study of a Plunging NACA0012 Airfoil under Asymmetric OscillationsBiomiméticaCinemática AssimétricaPerfil OscilanteVór- Tices de Bordo de FugaVórtices de Bordo de AtaqueDomínio/Área Científica::Engenharia e Tecnologia::Engenharia AeronáuticaThe need to overcome new challenges made the human being seek in nature ways to surpass specific problems through Biomimetics. Through the observation of locomotion modes of animals such as birds and insects, a great interest emerged in this form of motion that allows the simultaneous generation of thrust and lift at low Reynolds numbers. This dissertation has the primary objective of exploring experimentally the asymmetric movement of a NACA0012 airfoil in purely vertical motion. It is also intended to study the influence of the nondimensional amplitude and reduced frequency on the wake patterns of the airfoil. Finally, will be performed an analysis of the influence of motion asymmetry, nondimensional amplitude and reduced frequency on the airfoil’s effective angle of attack. The tests are carried out in an open-section wind tunnel using a smoke machine to mark the flow and a highspeed camera to capture the airfoil’s wake. All tests are performed with a Reynolds number of 1 × 104 and four levels of asymmetry, ? = 0.5, ? = 0.6, ? = 0.7 and ? = 0.8, are considered. The nondimensional amplitude studied is between 0.125 and 0.5, and the reduced frequency ranges between 0.5 and 8. The visualization of the flow indicates that the asymmetric motion produces both thrust and lift and that increasing the asymmetry parameter makes the vorticity more intense. Furthermore, these vortices form earlier. Nondimensional amplitude and reduced frequency have a similar impact. It is found that vortices form further upstream with the increase of these parameters, and their intensity also increases. Regarding the effective angle of attack, it is observed through the results that the rise of these three parameters causes an increase in this angle. The separation of the flow occurs earlier for higher values of the asymmetry parameter, nondimensional amplitude and reduced frequency.Novos desafios fizeram com que o Homem sentisse a necessidade de procurar na natureza, através da Biomimética, formas de ultrapassar variados problemas. Através da observação das formas de locomoção de animais como pássaros e insetos, surgiu um grande interesse nesta forma de locomoção que permite a simultânea geração de propulsão e sustentação, no que é considerado um regime de baixo número de Reynolds. Esta dissertação tem como principal objetivo o estudo experimental do movimento assimétrico de um perfil NACA0012 em movimento puramente vertical. Também se pretende estudar a influência da amplitude adimensional e da frequência reduzida nos padrões de esteira deste perfil. Por fim, será realizada uma análise da influência da assimetria do movimento, da amplitude adimensional e da frequência reduzida no ângulo de ataque efetivo do perfil. Os testes são realizados num túnel de vento de secção aberta utilizando-se uma máquina de fumo para marcar o escoamento e uma câmara de alta velocidade para captar a esteira do perfil. Todos os testes são realizados com um número de Reynolds de 1×104 , considerando-se quatro níveis de assimetria, ? = 0.5, ? = 0.6, ? = 0.7 e ? = 0.8. A amplitude adimensional estudada encontra-se entre 0.125 e 0.5 e a frequência reduzida entre 0.5 e 8. A visualização do escoamento indica que o movimento assimétrico produz simultaneamente tração e sustentação e que o aumento do parâmetro de assimetria torna a vorticidade mais intensa, fazendo com que estes vórtices se formem mais cedo. A amplitude adimensional e a frequência reduzida têm um impacto semelhante. Verifica-se que com o aumento destes parâmetros, os vórtices formam-se mais a montante, sendo que a sua intensidade também aumenta. Relativamente ao ângulo de ataque efetivo, observa-se através dos resultados obtidos, que o aumento destes três parâmetros provoca um aumento neste ângulo, embora de diferentes formas. A separação do escoamento ocorre mais cedo para maiores valores do parâmetro de assimetria e amplitude adimensional.Silva, André Resende Rodrigues dauBibliorumSilva, Joana Gomes Santos2023-11-23T11:27:35Z2023-03-022023-01-182023-03-02T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10400.6/13764TID:203390130enginfo: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:RCAAP2023-12-15T09:57:28Zoai:ubibliorum.ubi.pt:10400.6/13764Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T00:53:07.956413Repositório 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 |
Experimental Study of a Plunging NACA0012 Airfoil under Asymmetric Oscillations |
title |
Experimental Study of a Plunging NACA0012 Airfoil under Asymmetric Oscillations |
spellingShingle |
Experimental Study of a Plunging NACA0012 Airfoil under Asymmetric Oscillations Silva, Joana Gomes Santos Biomimética Cinemática Assimétrica Perfil Oscilante Vór- Tices de Bordo de Fuga Vórtices de Bordo de Ataque Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica |
title_short |
Experimental Study of a Plunging NACA0012 Airfoil under Asymmetric Oscillations |
title_full |
Experimental Study of a Plunging NACA0012 Airfoil under Asymmetric Oscillations |
title_fullStr |
Experimental Study of a Plunging NACA0012 Airfoil under Asymmetric Oscillations |
title_full_unstemmed |
Experimental Study of a Plunging NACA0012 Airfoil under Asymmetric Oscillations |
title_sort |
Experimental Study of a Plunging NACA0012 Airfoil under Asymmetric Oscillations |
author |
Silva, Joana Gomes Santos |
author_facet |
Silva, Joana Gomes Santos |
author_role |
author |
dc.contributor.none.fl_str_mv |
Silva, André Resende Rodrigues da uBibliorum |
dc.contributor.author.fl_str_mv |
Silva, Joana Gomes Santos |
dc.subject.por.fl_str_mv |
Biomimética Cinemática Assimétrica Perfil Oscilante Vór- Tices de Bordo de Fuga Vórtices de Bordo de Ataque Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica |
topic |
Biomimética Cinemática Assimétrica Perfil Oscilante Vór- Tices de Bordo de Fuga Vórtices de Bordo de Ataque Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Aeronáutica |
description |
The need to overcome new challenges made the human being seek in nature ways to surpass specific problems through Biomimetics. Through the observation of locomotion modes of animals such as birds and insects, a great interest emerged in this form of motion that allows the simultaneous generation of thrust and lift at low Reynolds numbers. This dissertation has the primary objective of exploring experimentally the asymmetric movement of a NACA0012 airfoil in purely vertical motion. It is also intended to study the influence of the nondimensional amplitude and reduced frequency on the wake patterns of the airfoil. Finally, will be performed an analysis of the influence of motion asymmetry, nondimensional amplitude and reduced frequency on the airfoil’s effective angle of attack. The tests are carried out in an open-section wind tunnel using a smoke machine to mark the flow and a highspeed camera to capture the airfoil’s wake. All tests are performed with a Reynolds number of 1 × 104 and four levels of asymmetry, ? = 0.5, ? = 0.6, ? = 0.7 and ? = 0.8, are considered. The nondimensional amplitude studied is between 0.125 and 0.5, and the reduced frequency ranges between 0.5 and 8. The visualization of the flow indicates that the asymmetric motion produces both thrust and lift and that increasing the asymmetry parameter makes the vorticity more intense. Furthermore, these vortices form earlier. Nondimensional amplitude and reduced frequency have a similar impact. It is found that vortices form further upstream with the increase of these parameters, and their intensity also increases. Regarding the effective angle of attack, it is observed through the results that the rise of these three parameters causes an increase in this angle. The separation of the flow occurs earlier for higher values of the asymmetry parameter, nondimensional amplitude and reduced frequency. |
publishDate |
2023 |
dc.date.none.fl_str_mv |
2023-11-23T11:27:35Z 2023-03-02 2023-01-18 2023-03-02T00:00:00Z |
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/10400.6/13764 TID:203390130 |
url |
http://hdl.handle.net/10400.6/13764 |
identifier_str_mv |
TID:203390130 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
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openAccess |
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application/pdf |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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1799136419906584576 |