SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb seal
Autor(a) principal: | |
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Data de Publicação: | 2021 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1017/jfm.2021.93 http://hdl.handle.net/11449/206159 |
Resumo: | The slat represents an important airframe noise source as it extends over almost the entire aircraft wingspan. Most studies of slat noise consider idealized geometries. However, for practical applications, several elements are installed on its cove, such as bulb seals to avoid direct contact with the main wing surface. Previous investigations of an unswept and untapered MD30P30N airfoil reported that the flow dynamics and the corresponding acoustic noise are very sensitive to the presence and location of the bulb seal. For certain locations a second recirculation bubble is created inside the slat cove and the acoustic narrowband peaks are intensified. The present paper shows that the two-bubble topology promotes the recirculation of turbulence within the slat cove. Spectral proper orthogonal decomposition analysis based on the radiated pressure intensity is used to identify the flow structures responsible for sound generation. Even though the recirculating turbulence is mostly incoherent, it interacts with the coherent Kelvin-Helmholtz vortices in the initial part of the mixing layer. Then, vortex merging and straining lead to the formation of complex vortex clusters. Our results show that the origin and evolution of these clusters are consistent with Rossiter's mechanism responsible for the narrowband peaks. The enhanced recirculation accelerates the cluster evolution leading to wider clusters and lower-frequency Rossiter modes. |
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SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb sealaeroacousticslow-dimensional modelsvortex interactionsThe slat represents an important airframe noise source as it extends over almost the entire aircraft wingspan. Most studies of slat noise consider idealized geometries. However, for practical applications, several elements are installed on its cove, such as bulb seals to avoid direct contact with the main wing surface. Previous investigations of an unswept and untapered MD30P30N airfoil reported that the flow dynamics and the corresponding acoustic noise are very sensitive to the presence and location of the bulb seal. For certain locations a second recirculation bubble is created inside the slat cove and the acoustic narrowband peaks are intensified. The present paper shows that the two-bubble topology promotes the recirculation of turbulence within the slat cove. Spectral proper orthogonal decomposition analysis based on the radiated pressure intensity is used to identify the flow structures responsible for sound generation. Even though the recirculating turbulence is mostly incoherent, it interacts with the coherent Kelvin-Helmholtz vortices in the initial part of the mixing layer. Then, vortex merging and straining lead to the formation of complex vortex clusters. Our results show that the origin and evolution of these clusters are consistent with Rossiter's mechanism responsible for the narrowband peaks. The enhanced recirculation accelerates the cluster evolution leading to wider clusters and lower-frequency Rossiter modes.Department of Aeronautical Engineering University of São Paulo, Av. Trabalhador São Carlense, 400UNESP-São Paulo State University, Av. Profa. Isette Correa Fontão 505Aeronautics Institute of Technology, Praça Marechal Eduardo Gomes 50ETSIAE-UPM (School of Aeronautics) Universidad Politécnica de Madrid, Plaza del Cardenal Cisneros 3UNESP-São Paulo State University, Av. Profa. Isette Correa Fontão 505Universidade de São Paulo (USP)Universidade Estadual Paulista (Unesp)Aeronautics Institute of TechnologyUniversidad Politécnica de MadridHimeno, Fernando H.T.Souza, Daniel S. [UNESP]Amaral, Filipe R.Rodríguez, DanielMedeiros, Marcello A.F.2021-06-25T10:27:34Z2021-06-25T10:27:34Z2021-01-01info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://dx.doi.org/10.1017/jfm.2021.93Journal of Fluid Mechanics, v. 915.1469-76450022-1120http://hdl.handle.net/11449/20615910.1017/jfm.2021.932-s2.0-85103776969Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengJournal of Fluid Mechanicsinfo:eu-repo/semantics/openAccess2021-10-22T21:16:13Zoai:repositorio.unesp.br:11449/206159Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T20:36:41.551544Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb seal |
title |
SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb seal |
spellingShingle |
SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb seal Himeno, Fernando H.T. aeroacoustics low-dimensional models vortex interactions |
title_short |
SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb seal |
title_full |
SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb seal |
title_fullStr |
SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb seal |
title_full_unstemmed |
SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb seal |
title_sort |
SPOD analysis of noise-generating Rossiter modes in a slat with and without a bulb seal |
author |
Himeno, Fernando H.T. |
author_facet |
Himeno, Fernando H.T. Souza, Daniel S. [UNESP] Amaral, Filipe R. Rodríguez, Daniel Medeiros, Marcello A.F. |
author_role |
author |
author2 |
Souza, Daniel S. [UNESP] Amaral, Filipe R. Rodríguez, Daniel Medeiros, Marcello A.F. |
author2_role |
author author author author |
dc.contributor.none.fl_str_mv |
Universidade de São Paulo (USP) Universidade Estadual Paulista (Unesp) Aeronautics Institute of Technology Universidad Politécnica de Madrid |
dc.contributor.author.fl_str_mv |
Himeno, Fernando H.T. Souza, Daniel S. [UNESP] Amaral, Filipe R. Rodríguez, Daniel Medeiros, Marcello A.F. |
dc.subject.por.fl_str_mv |
aeroacoustics low-dimensional models vortex interactions |
topic |
aeroacoustics low-dimensional models vortex interactions |
description |
The slat represents an important airframe noise source as it extends over almost the entire aircraft wingspan. Most studies of slat noise consider idealized geometries. However, for practical applications, several elements are installed on its cove, such as bulb seals to avoid direct contact with the main wing surface. Previous investigations of an unswept and untapered MD30P30N airfoil reported that the flow dynamics and the corresponding acoustic noise are very sensitive to the presence and location of the bulb seal. For certain locations a second recirculation bubble is created inside the slat cove and the acoustic narrowband peaks are intensified. The present paper shows that the two-bubble topology promotes the recirculation of turbulence within the slat cove. Spectral proper orthogonal decomposition analysis based on the radiated pressure intensity is used to identify the flow structures responsible for sound generation. Even though the recirculating turbulence is mostly incoherent, it interacts with the coherent Kelvin-Helmholtz vortices in the initial part of the mixing layer. Then, vortex merging and straining lead to the formation of complex vortex clusters. Our results show that the origin and evolution of these clusters are consistent with Rossiter's mechanism responsible for the narrowband peaks. The enhanced recirculation accelerates the cluster evolution leading to wider clusters and lower-frequency Rossiter modes. |
publishDate |
2021 |
dc.date.none.fl_str_mv |
2021-06-25T10:27:34Z 2021-06-25T10:27:34Z 2021-01-01 |
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/10.1017/jfm.2021.93 Journal of Fluid Mechanics, v. 915. 1469-7645 0022-1120 http://hdl.handle.net/11449/206159 10.1017/jfm.2021.93 2-s2.0-85103776969 |
url |
http://dx.doi.org/10.1017/jfm.2021.93 http://hdl.handle.net/11449/206159 |
identifier_str_mv |
Journal of Fluid Mechanics, v. 915. 1469-7645 0022-1120 10.1017/jfm.2021.93 2-s2.0-85103776969 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Journal of Fluid Mechanics |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
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 |
|
_version_ |
1808129226143956992 |