CFD and CAA analysis of single stream isothermal jets with noise suppression devices.
Autor(a) principal: | |
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Data de Publicação: | 2009 |
Tipo de documento: | Dissertação |
Idioma: | eng |
Título da fonte: | Biblioteca Digital de Teses e Dissertações do ITA |
Texto Completo: | http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1210 |
Resumo: | Since the 50's, with the appearance of the turbojet engines, the jet noise is being exhaustively studied, because it is one of the most important source of aircraft noise. Many attempts have been made to reduce the jet noise, including higher by-pass turbofan engines. Chevron nozzles also have been used by the industry to try to reduce the jet noise with a low performance and weight penalty. This work shows a computation procedure to assess how this noise suppression devices impact on both fluid dynamics and acoustics of single isothermal jets. Towards this goal, different chevron nozzles, with 6, 8 and 12 lobes have been analyzed. The calculation procedure is based on a Reynolds Average Navier-Stokes calculation, followed by a stochastic noise generation and radiation method, resulting in a relatively fast noise calculation procedure. The simulations have been carried out using the commercial software CFD++. The calculation procedure has predicted the expected fluid dynamic and acoustic behavior for chevron nozzles, e.g., shortening the potential core length, high frequency noise increase and low frequency noise attenuation. The parametric study of the number of lobes has shown that this parameter impacts the mixing region. Moreover, varying this parameter is a way to attain different low frequency reductions, without great impacts on the highest frequencies. Although the procedure did not capture correctly the absolute values of the acoustic response, the results show that this relatively simple and quick analysis reproduced important parameters in designing new nozzles and can be used as a way to better understand the influence of chevrons. |
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Biblioteca Digital de Teses e Dissertações do ITA |
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CFD and CAA analysis of single stream isothermal jets with noise suppression devices.Motores turbojatoProjeto de tubeiraRedução de ruídoAeroacústicaDinâmica dos fluidos computacionalRuído de aeronavesEngenharia mecânicaEngenharia aeronáuticaSince the 50's, with the appearance of the turbojet engines, the jet noise is being exhaustively studied, because it is one of the most important source of aircraft noise. Many attempts have been made to reduce the jet noise, including higher by-pass turbofan engines. Chevron nozzles also have been used by the industry to try to reduce the jet noise with a low performance and weight penalty. This work shows a computation procedure to assess how this noise suppression devices impact on both fluid dynamics and acoustics of single isothermal jets. Towards this goal, different chevron nozzles, with 6, 8 and 12 lobes have been analyzed. The calculation procedure is based on a Reynolds Average Navier-Stokes calculation, followed by a stochastic noise generation and radiation method, resulting in a relatively fast noise calculation procedure. The simulations have been carried out using the commercial software CFD++. The calculation procedure has predicted the expected fluid dynamic and acoustic behavior for chevron nozzles, e.g., shortening the potential core length, high frequency noise increase and low frequency noise attenuation. The parametric study of the number of lobes has shown that this parameter impacts the mixing region. Moreover, varying this parameter is a way to attain different low frequency reductions, without great impacts on the highest frequencies. Although the procedure did not capture correctly the absolute values of the acoustic response, the results show that this relatively simple and quick analysis reproduced important parameters in designing new nozzles and can be used as a way to better understand the influence of chevrons.Instituto Tecnológico de AeronáuticaOdenir de AlmeidaJoão Roberto BarbosaBernardo Santos Aflalo2009-04-13info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesishttp://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1210reponame:Biblioteca Digital de Teses e Dissertações do ITAinstname:Instituto Tecnológico de Aeronáuticainstacron:ITAenginfo:eu-repo/semantics/openAccessapplication/pdf2019-02-02T14:02:36Zoai:agregador.ibict.br.BDTD_ITA:oai:ita.br:1210http://oai.bdtd.ibict.br/requestopendoar:null2020-05-28 19:35:43.555Biblioteca Digital de Teses e Dissertações do ITA - Instituto Tecnológico de Aeronáuticatrue |
dc.title.none.fl_str_mv |
CFD and CAA analysis of single stream isothermal jets with noise suppression devices. |
title |
CFD and CAA analysis of single stream isothermal jets with noise suppression devices. |
spellingShingle |
CFD and CAA analysis of single stream isothermal jets with noise suppression devices. Bernardo Santos Aflalo Motores turbojato Projeto de tubeira Redução de ruído Aeroacústica Dinâmica dos fluidos computacional Ruído de aeronaves Engenharia mecânica Engenharia aeronáutica |
title_short |
CFD and CAA analysis of single stream isothermal jets with noise suppression devices. |
title_full |
CFD and CAA analysis of single stream isothermal jets with noise suppression devices. |
title_fullStr |
CFD and CAA analysis of single stream isothermal jets with noise suppression devices. |
title_full_unstemmed |
CFD and CAA analysis of single stream isothermal jets with noise suppression devices. |
title_sort |
CFD and CAA analysis of single stream isothermal jets with noise suppression devices. |
author |
Bernardo Santos Aflalo |
author_facet |
Bernardo Santos Aflalo |
author_role |
author |
dc.contributor.none.fl_str_mv |
Odenir de Almeida João Roberto Barbosa |
dc.contributor.author.fl_str_mv |
Bernardo Santos Aflalo |
dc.subject.por.fl_str_mv |
Motores turbojato Projeto de tubeira Redução de ruído Aeroacústica Dinâmica dos fluidos computacional Ruído de aeronaves Engenharia mecânica Engenharia aeronáutica |
topic |
Motores turbojato Projeto de tubeira Redução de ruído Aeroacústica Dinâmica dos fluidos computacional Ruído de aeronaves Engenharia mecânica Engenharia aeronáutica |
dc.description.none.fl_txt_mv |
Since the 50's, with the appearance of the turbojet engines, the jet noise is being exhaustively studied, because it is one of the most important source of aircraft noise. Many attempts have been made to reduce the jet noise, including higher by-pass turbofan engines. Chevron nozzles also have been used by the industry to try to reduce the jet noise with a low performance and weight penalty. This work shows a computation procedure to assess how this noise suppression devices impact on both fluid dynamics and acoustics of single isothermal jets. Towards this goal, different chevron nozzles, with 6, 8 and 12 lobes have been analyzed. The calculation procedure is based on a Reynolds Average Navier-Stokes calculation, followed by a stochastic noise generation and radiation method, resulting in a relatively fast noise calculation procedure. The simulations have been carried out using the commercial software CFD++. The calculation procedure has predicted the expected fluid dynamic and acoustic behavior for chevron nozzles, e.g., shortening the potential core length, high frequency noise increase and low frequency noise attenuation. The parametric study of the number of lobes has shown that this parameter impacts the mixing region. Moreover, varying this parameter is a way to attain different low frequency reductions, without great impacts on the highest frequencies. Although the procedure did not capture correctly the absolute values of the acoustic response, the results show that this relatively simple and quick analysis reproduced important parameters in designing new nozzles and can be used as a way to better understand the influence of chevrons. |
description |
Since the 50's, with the appearance of the turbojet engines, the jet noise is being exhaustively studied, because it is one of the most important source of aircraft noise. Many attempts have been made to reduce the jet noise, including higher by-pass turbofan engines. Chevron nozzles also have been used by the industry to try to reduce the jet noise with a low performance and weight penalty. This work shows a computation procedure to assess how this noise suppression devices impact on both fluid dynamics and acoustics of single isothermal jets. Towards this goal, different chevron nozzles, with 6, 8 and 12 lobes have been analyzed. The calculation procedure is based on a Reynolds Average Navier-Stokes calculation, followed by a stochastic noise generation and radiation method, resulting in a relatively fast noise calculation procedure. The simulations have been carried out using the commercial software CFD++. The calculation procedure has predicted the expected fluid dynamic and acoustic behavior for chevron nozzles, e.g., shortening the potential core length, high frequency noise increase and low frequency noise attenuation. The parametric study of the number of lobes has shown that this parameter impacts the mixing region. Moreover, varying this parameter is a way to attain different low frequency reductions, without great impacts on the highest frequencies. Although the procedure did not capture correctly the absolute values of the acoustic response, the results show that this relatively simple and quick analysis reproduced important parameters in designing new nozzles and can be used as a way to better understand the influence of chevrons. |
publishDate |
2009 |
dc.date.none.fl_str_mv |
2009-04-13 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/publishedVersion info:eu-repo/semantics/masterThesis |
status_str |
publishedVersion |
format |
masterThesis |
dc.identifier.uri.fl_str_mv |
http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1210 |
url |
http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=1210 |
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 Tecnológico de Aeronáutica |
publisher.none.fl_str_mv |
Instituto Tecnológico de Aeronáutica |
dc.source.none.fl_str_mv |
reponame:Biblioteca Digital de Teses e Dissertações do ITA instname:Instituto Tecnológico de Aeronáutica instacron:ITA |
reponame_str |
Biblioteca Digital de Teses e Dissertações do ITA |
collection |
Biblioteca Digital de Teses e Dissertações do ITA |
instname_str |
Instituto Tecnológico de Aeronáutica |
instacron_str |
ITA |
institution |
ITA |
repository.name.fl_str_mv |
Biblioteca Digital de Teses e Dissertações do ITA - Instituto Tecnológico de Aeronáutica |
repository.mail.fl_str_mv |
|
subject_por_txtF_mv |
Motores turbojato Projeto de tubeira Redução de ruído Aeroacústica Dinâmica dos fluidos computacional Ruído de aeronaves Engenharia mecânica Engenharia aeronáutica |
_version_ |
1706809267340705792 |