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 UFRGS |
Texto Completo: | http://hdl.handle.net/10183/75787 |
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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Martinez, Denise Maria VarellaCamaño Schettini, Edith BeatrizSilvestrini, Jorge Hugo2013-07-11T02:22:07Z20061678-5878http://hdl.handle.net/10183/75787000525131The 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.application/pdfengJournal of Brazilian Society of Mechanical Sciences and Engineering. Rio de Janeiro, RJ: ABCM. Vol. 28, n. 2 (April/June 2006), p. 230-240TurbulênciaStable stratificationDirect numerical simulationMixing layerBuoyancy forceTransition to turbulenceThe influence of stable stratification on the transition to turbulence in a temporal mixing layerinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/otherinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSORIGINAL000525131.pdf000525131.pdfTexto completo (inglês)application/pdf483095http://www.lume.ufrgs.br/bitstream/10183/75787/1/000525131.pdf6b9fde33a4b692ed0d16417596adc67bMD51TEXT000525131.pdf.txt000525131.pdf.txtExtracted Texttext/plain40455http://www.lume.ufrgs.br/bitstream/10183/75787/2/000525131.pdf.txt2b083c06f7df6ac4249269a5e300c2c4MD52THUMBNAIL000525131.pdf.jpg000525131.pdf.jpgGenerated Thumbnailimage/jpeg1971http://www.lume.ufrgs.br/bitstream/10183/75787/3/000525131.pdf.jpg544a6b54265388f881abb74a88c9346aMD5310183/757872023-04-06 03:29:27.31481oai:www.lume.ufrgs.br:10183/75787Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2023-04-06T06:29:27Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.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 Turbulência 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 Camaño Schettini, Edith Beatriz Silvestrini, Jorge Hugo |
author_role |
author |
author2 |
Camaño Schettini, Edith Beatriz Silvestrini, Jorge Hugo |
author2_role |
author author |
dc.contributor.author.fl_str_mv |
Martinez, Denise Maria Varella Camaño Schettini, Edith Beatriz Silvestrini, Jorge Hugo |
dc.subject.por.fl_str_mv |
Turbulência |
topic |
Turbulência Stable stratification Direct numerical simulation Mixing layer Buoyancy force Transition to turbulence |
dc.subject.eng.fl_str_mv |
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.issued.fl_str_mv |
2006 |
dc.date.accessioned.fl_str_mv |
2013-07-11T02:22:07Z |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/other |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
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publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/75787 |
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1678-5878 |
dc.identifier.nrb.pt_BR.fl_str_mv |
000525131 |
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1678-5878 000525131 |
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http://hdl.handle.net/10183/75787 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
Journal of Brazilian Society of Mechanical Sciences and Engineering. Rio de Janeiro, RJ: ABCM. Vol. 28, n. 2 (April/June 2006), p. 230-240 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
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application/pdf |
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