The influence of stable stratification on the transition to turbulence in a temporal mixing layer
Autor(a) principal: | |
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Data de Publicação: | 2006 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da FURG (RI FURG) |
Texto Completo: | http://repositorio.furg.br/handle/1/1069 |
Resumo: | The transition to turbulence in a stably stratified flow is a problem of considerable interest in fluid dynamics with applications in both geophysical sciences and engineering. This transition is controlled by competition between the vertical shear of the base flow and the buoyancy forces due to the density stratification. The present work investigates numerically the effect of stable stratification on the development of a Kelvin-Helmholtz (KH) instability and the formation of streamwise vortices, which are developed after the saturation of the primary billows of KH. The Direct Numerical Simulation (DNS) technique was used to solve the complete Navier-Stokes equations, in the Boussinesq approximation. Numerical tests were done with different Richardson numbers and forced initial conditions for velocity fluctuations. The results showed that high stratification inhibits the pairing process, reduces the buoyancy flux, weakens the vertical motions, decreases the thickness of the mixing layer and affects the formation of streamwise vortices. The three-dimensional results demonstrated that the streamwise vortices are clearly formed in non-stratified cases. In the stratified cases, on the other hand, the streamwise vortices are weakened, due to the streamwise density gradient, which decrease the levels of vorticity in the billows of KH, while increase in the braid zone. |
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The influence of stable stratification on the transition to turbulence in a temporal mixing layerStable stratificationDirect numerical simulationMixing layerBuoyancy force,Transition to turbulenceThe transition to turbulence in a stably stratified flow is a problem of considerable interest in fluid dynamics with applications in both geophysical sciences and engineering. This transition is controlled by competition between the vertical shear of the base flow and the buoyancy forces due to the density stratification. The present work investigates numerically the effect of stable stratification on the development of a Kelvin-Helmholtz (KH) instability and the formation of streamwise vortices, which are developed after the saturation of the primary billows of KH. The Direct Numerical Simulation (DNS) technique was used to solve the complete Navier-Stokes equations, in the Boussinesq approximation. Numerical tests were done with different Richardson numbers and forced initial conditions for velocity fluctuations. The results showed that high stratification inhibits the pairing process, reduces the buoyancy flux, weakens the vertical motions, decreases the thickness of the mixing layer and affects the formation of streamwise vortices. The three-dimensional results demonstrated that the streamwise vortices are clearly formed in non-stratified cases. In the stratified cases, on the other hand, the streamwise vortices are weakened, due to the streamwise density gradient, which decrease the levels of vorticity in the billows of KH, while increase in the braid zone.2011-10-01T04:19:29Z2011-10-01T04:19:29Z2006info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfMARTINEZ, D. M. V..; SCHETTINI, E.B. C.; SILVESTRINI, J. H.. The influence of stable stratification on the transition to turbulence in a temporal mixing layer. J. Braz. Soc. Mech. Sci. & Eng. 2006, vol. 28, n. 2, p. 242-252. Disponível em: <http://www.scielo.br/pdf/jbsmse/v28n2/29757.pdf> Acesso em: 30 set. 2011.1678-5878http://repositorio.furg.br/handle/1/106910.1590/S1678-58782006000200014engMartinez, Denise Maria VarellaSchettini, Edith Beatriz CamañoSilvestrini, Jorge Hugoinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da FURG (RI FURG)instname:Universidade Federal do Rio Grande (FURG)instacron:FURG2022-10-21T18:16:38Zoai:repositorio.furg.br:1/1069Repositório InstitucionalPUBhttps://repositorio.furg.br/oai/request || http://200.19.254.174/oai/requestopendoar:2022-10-21T18:16:38Repositório Institucional da FURG (RI FURG) - Universidade Federal do Rio Grande (FURG)false |
dc.title.none.fl_str_mv |
The influence of stable stratification on the transition to turbulence in a temporal mixing layer |
title |
The influence of stable stratification on the transition to turbulence in a temporal mixing layer |
spellingShingle |
The influence of stable stratification on the transition to turbulence in a temporal mixing layer Martinez, Denise Maria Varella Stable stratification Direct numerical simulation Mixing layer Buoyancy force, Transition to turbulence |
title_short |
The influence of stable stratification on the transition to turbulence in a temporal mixing layer |
title_full |
The influence of stable stratification on the transition to turbulence in a temporal mixing layer |
title_fullStr |
The influence of stable stratification on the transition to turbulence in a temporal mixing layer |
title_full_unstemmed |
The influence of stable stratification on the transition to turbulence in a temporal mixing layer |
title_sort |
The influence of stable stratification on the transition to turbulence in a temporal mixing layer |
author |
Martinez, Denise Maria Varella |
author_facet |
Martinez, Denise Maria Varella Schettini, Edith Beatriz Camaño Silvestrini, Jorge Hugo |
author_role |
author |
author2 |
Schettini, Edith Beatriz Camaño Silvestrini, Jorge Hugo |
author2_role |
author author |
dc.contributor.author.fl_str_mv |
Martinez, Denise Maria Varella Schettini, Edith Beatriz Camaño Silvestrini, Jorge Hugo |
dc.subject.por.fl_str_mv |
Stable stratification Direct numerical simulation Mixing layer Buoyancy force, Transition to turbulence |
topic |
Stable stratification Direct numerical simulation Mixing layer Buoyancy force, Transition to turbulence |
description |
The transition to turbulence in a stably stratified flow is a problem of considerable interest in fluid dynamics with applications in both geophysical sciences and engineering. This transition is controlled by competition between the vertical shear of the base flow and the buoyancy forces due to the density stratification. The present work investigates numerically the effect of stable stratification on the development of a Kelvin-Helmholtz (KH) instability and the formation of streamwise vortices, which are developed after the saturation of the primary billows of KH. The Direct Numerical Simulation (DNS) technique was used to solve the complete Navier-Stokes equations, in the Boussinesq approximation. Numerical tests were done with different Richardson numbers and forced initial conditions for velocity fluctuations. The results showed that high stratification inhibits the pairing process, reduces the buoyancy flux, weakens the vertical motions, decreases the thickness of the mixing layer and affects the formation of streamwise vortices. The three-dimensional results demonstrated that the streamwise vortices are clearly formed in non-stratified cases. In the stratified cases, on the other hand, the streamwise vortices are weakened, due to the streamwise density gradient, which decrease the levels of vorticity in the billows of KH, while increase in the braid zone. |
publishDate |
2006 |
dc.date.none.fl_str_mv |
2006 2011-10-01T04:19:29Z 2011-10-01T04:19:29Z |
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 |
MARTINEZ, D. M. V..; SCHETTINI, E.B. C.; SILVESTRINI, J. H.. The influence of stable stratification on the transition to turbulence in a temporal mixing layer. J. Braz. Soc. Mech. Sci. & Eng. 2006, vol. 28, n. 2, p. 242-252. Disponível em: <http://www.scielo.br/pdf/jbsmse/v28n2/29757.pdf> Acesso em: 30 set. 2011. 1678-5878 http://repositorio.furg.br/handle/1/1069 10.1590/S1678-58782006000200014 |
identifier_str_mv |
MARTINEZ, D. M. V..; SCHETTINI, E.B. C.; SILVESTRINI, J. H.. The influence of stable stratification on the transition to turbulence in a temporal mixing layer. J. Braz. Soc. Mech. Sci. & Eng. 2006, vol. 28, n. 2, p. 242-252. Disponível em: <http://www.scielo.br/pdf/jbsmse/v28n2/29757.pdf> Acesso em: 30 set. 2011. 1678-5878 10.1590/S1678-58782006000200014 |
url |
http://repositorio.furg.br/handle/1/1069 |
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.source.none.fl_str_mv |
reponame:Repositório Institucional da FURG (RI FURG) instname:Universidade Federal do Rio Grande (FURG) instacron:FURG |
instname_str |
Universidade Federal do Rio Grande (FURG) |
instacron_str |
FURG |
institution |
FURG |
reponame_str |
Repositório Institucional da FURG (RI FURG) |
collection |
Repositório Institucional da FURG (RI FURG) |
repository.name.fl_str_mv |
Repositório Institucional da FURG (RI FURG) - Universidade Federal do Rio Grande (FURG) |
repository.mail.fl_str_mv |
|
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1807384417328431104 |