Numerical simulation of complex fluid flows with moving interfaces
Autor(a) principal: | |
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Data de Publicação: | 2023 |
Tipo de documento: | Tese |
Idioma: | eng |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da USP |
Texto Completo: | https://www.teses.usp.br/teses/disponiveis/55/55134/tde-30082023-150314/ |
Resumo: | Flows of different types of non-Newtonian fluids are numerically investigated with a focus on complex problems, as for instance confined flows in geometries with singularities and moving interface flows with surface tension. For confined geometries, the novel natural stress formulation is used to represent the polymeric stress tensor in viscoelastic flows, and we show that greater accuracy is obtained near geometrical singularities in comparison to the traditional Cartesian formulation. For flows with a moving interface, we propose and validate a new algorithm based on machine learning to estimate the curvature in Front-Tracking interfaces, showing that it can provide similar results compared to more traditional approaches. Our viscoelastic implementation is tested with the Phan-Thien-Tanner model for the problem of binary droplet colisions. We provide maps of outcomes associated with the categories of Bouncing, Coalescence, and Separation as functions of the dimensionless numbers that govern the problem. In addition to the traditional Newtonian space defined by the Weber and the impact factor, associated with the collision angle, we also explore the Weissenberg number and the extensibility parameter in the PTT model. For non-bouncing scenarios, the results show that surface tension and elasticity act to maintain the integrity of the merged drop and avoid Separation. On the other hand, shearthinning effects induce the Separation outcome. Hence, in the PTT model there are opposite trends associated with elasticity and shear-thinning, what can lead to non-monotonic responses. We also study the spreading of an elastoviscoplastic droplet over a thin-film. By modelling an elastoviscoplastic material using Saramitos model, we perform a nondimensional analysis to understand the competition between surface tension and yield-stress, and how elasticity affects this balance. We can see that, for less viscous fluids, elasticity can greatly increase the spreading of a droplet, since the internal resisting stresses develop more slowly due to the polymeric relaxation time. This effect is more pronounced for materials of high yield-stress, which indicates elasticity has a greater impact for elastic solids than fluids. We believe the results in this thesis could shed light on the importance of elastic parameters in common industrial problems such as 3D printing with spreading of droplets or sprays with droplet coalescence and breakup. |
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Numerical simulation of complex fluid flows with moving interfacesSimulação numéricos de escoamentos de fluidos complexos com interfaces móveisComplex fluidsEscoamentos com superfície livreFluidos complexosFree surface flowsNumerical solutionSoluções numéricasFlows of different types of non-Newtonian fluids are numerically investigated with a focus on complex problems, as for instance confined flows in geometries with singularities and moving interface flows with surface tension. For confined geometries, the novel natural stress formulation is used to represent the polymeric stress tensor in viscoelastic flows, and we show that greater accuracy is obtained near geometrical singularities in comparison to the traditional Cartesian formulation. For flows with a moving interface, we propose and validate a new algorithm based on machine learning to estimate the curvature in Front-Tracking interfaces, showing that it can provide similar results compared to more traditional approaches. Our viscoelastic implementation is tested with the Phan-Thien-Tanner model for the problem of binary droplet colisions. We provide maps of outcomes associated with the categories of Bouncing, Coalescence, and Separation as functions of the dimensionless numbers that govern the problem. In addition to the traditional Newtonian space defined by the Weber and the impact factor, associated with the collision angle, we also explore the Weissenberg number and the extensibility parameter in the PTT model. For non-bouncing scenarios, the results show that surface tension and elasticity act to maintain the integrity of the merged drop and avoid Separation. On the other hand, shearthinning effects induce the Separation outcome. Hence, in the PTT model there are opposite trends associated with elasticity and shear-thinning, what can lead to non-monotonic responses. We also study the spreading of an elastoviscoplastic droplet over a thin-film. By modelling an elastoviscoplastic material using Saramitos model, we perform a nondimensional analysis to understand the competition between surface tension and yield-stress, and how elasticity affects this balance. We can see that, for less viscous fluids, elasticity can greatly increase the spreading of a droplet, since the internal resisting stresses develop more slowly due to the polymeric relaxation time. This effect is more pronounced for materials of high yield-stress, which indicates elasticity has a greater impact for elastic solids than fluids. We believe the results in this thesis could shed light on the importance of elastic parameters in common industrial problems such as 3D printing with spreading of droplets or sprays with droplet coalescence and breakup.Escoamentos de diferentes tipos de fluidos não-newtonianos são numericamente investigados com foco em problemas complexos, como por exemplo escoamentos confinados em geometrias com singularidades e escoamentos com interfaces móveis e tensão superficial. Em geometrias confinadas, a formulação tensão natural é usada para representar o tensor tensão polimérico em escoamentos viscoelásticos. Uma maior precisão é obtida próximo a singularidades geométricas em comparação com a tradicional formulação cartesiana. Em escoamentos com interfaces móveis, um novo algoritmo baseado em aprendizado de máquina é proposto e validado para o cálculo da curvatura de interfaces Front-Tracking. Verifica-se que é possível obter resultados similares aos obtidos por abordagens mais tradicionais. A implementação viscoelástica é testada com o modelo Phan-Thien-Tanner para o problema da colisão binária de gotas. Mapas paramétricos são obtidos, classificando os resultados nas categorias bouncing, coalescência, e separação em função de números adimensionais que governam o problema. Além do espaço tradicional Newtoniano definido pelo número de Weber e o fator de impacto, também explora-se o número de Weissenberg e o parâmetro de extensibilidade PTT. Para casos sem bouncing, os resultados mostram que a tensão superficial e elasticidade mantém a integridade da gota, inibindo a separação da mesma. Por outro lado, efeitos shear-thinning induzem a separação. Deste modo, no modelo PTT existem tendências opostas associadas a elasticidade e ao shear-thinning, o que pode levar a respostas não-monotônicas. Também é estudado o espalhamento de uma gota elastoviscoplástica (EVP) sobre uma camada fina do mesmo fluido. Modelando o material EVP com o modelo de Saramito, realiza-se uma análise adimensional para entender a competição entre tensão superficial e tensão de escoamento, e como a elasticidade afeta este balanço. Observa-se que, para fluidos menos viscosos, elasticidade pode aumentar significativamente o espalhamento de uma gota, pois a tensão interna que resiste o escoamento se desenvolve mais lentamente devido ao tempo de relaxação polimérico. Este efeito é mais evidente em materiais com uma alta tensão de escoamento, o que indica que a elasticidade tem um maior impacto em sólidos elásticos do que em fluidos. Acredita-se que os resultados nesta tese podem esclarecer quanto a importância dos parâmetros elásticos em problemas industriais comuns como impressões 3D com espalhamento de gotas, ou sprays com coalescência de quebra de gotas.Biblioteca Digitais de Teses e Dissertações da USPCuminato, José AlbertoOishi, Cássio MachiaveliFrança, Hugo Leonardo2023-06-16info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttps://www.teses.usp.br/teses/disponiveis/55/55134/tde-30082023-150314/reponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USPLiberar o conteúdo para acesso público.info:eu-repo/semantics/openAccesseng2023-08-30T18:47:02Zoai:teses.usp.br:tde-30082023-150314Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212023-08-30T18:47:02Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
Numerical simulation of complex fluid flows with moving interfaces Simulação numéricos de escoamentos de fluidos complexos com interfaces móveis |
title |
Numerical simulation of complex fluid flows with moving interfaces |
spellingShingle |
Numerical simulation of complex fluid flows with moving interfaces França, Hugo Leonardo Complex fluids Escoamentos com superfície livre Fluidos complexos Free surface flows Numerical solution Soluções numéricas |
title_short |
Numerical simulation of complex fluid flows with moving interfaces |
title_full |
Numerical simulation of complex fluid flows with moving interfaces |
title_fullStr |
Numerical simulation of complex fluid flows with moving interfaces |
title_full_unstemmed |
Numerical simulation of complex fluid flows with moving interfaces |
title_sort |
Numerical simulation of complex fluid flows with moving interfaces |
author |
França, Hugo Leonardo |
author_facet |
França, Hugo Leonardo |
author_role |
author |
dc.contributor.none.fl_str_mv |
Cuminato, José Alberto Oishi, Cássio Machiaveli |
dc.contributor.author.fl_str_mv |
França, Hugo Leonardo |
dc.subject.por.fl_str_mv |
Complex fluids Escoamentos com superfície livre Fluidos complexos Free surface flows Numerical solution Soluções numéricas |
topic |
Complex fluids Escoamentos com superfície livre Fluidos complexos Free surface flows Numerical solution Soluções numéricas |
description |
Flows of different types of non-Newtonian fluids are numerically investigated with a focus on complex problems, as for instance confined flows in geometries with singularities and moving interface flows with surface tension. For confined geometries, the novel natural stress formulation is used to represent the polymeric stress tensor in viscoelastic flows, and we show that greater accuracy is obtained near geometrical singularities in comparison to the traditional Cartesian formulation. For flows with a moving interface, we propose and validate a new algorithm based on machine learning to estimate the curvature in Front-Tracking interfaces, showing that it can provide similar results compared to more traditional approaches. Our viscoelastic implementation is tested with the Phan-Thien-Tanner model for the problem of binary droplet colisions. We provide maps of outcomes associated with the categories of Bouncing, Coalescence, and Separation as functions of the dimensionless numbers that govern the problem. In addition to the traditional Newtonian space defined by the Weber and the impact factor, associated with the collision angle, we also explore the Weissenberg number and the extensibility parameter in the PTT model. For non-bouncing scenarios, the results show that surface tension and elasticity act to maintain the integrity of the merged drop and avoid Separation. On the other hand, shearthinning effects induce the Separation outcome. Hence, in the PTT model there are opposite trends associated with elasticity and shear-thinning, what can lead to non-monotonic responses. We also study the spreading of an elastoviscoplastic droplet over a thin-film. By modelling an elastoviscoplastic material using Saramitos model, we perform a nondimensional analysis to understand the competition between surface tension and yield-stress, and how elasticity affects this balance. We can see that, for less viscous fluids, elasticity can greatly increase the spreading of a droplet, since the internal resisting stresses develop more slowly due to the polymeric relaxation time. This effect is more pronounced for materials of high yield-stress, which indicates elasticity has a greater impact for elastic solids than fluids. We believe the results in this thesis could shed light on the importance of elastic parameters in common industrial problems such as 3D printing with spreading of droplets or sprays with droplet coalescence and breakup. |
publishDate |
2023 |
dc.date.none.fl_str_mv |
2023-06-16 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.teses.usp.br/teses/disponiveis/55/55134/tde-30082023-150314/ |
url |
https://www.teses.usp.br/teses/disponiveis/55/55134/tde-30082023-150314/ |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
|
dc.rights.driver.fl_str_mv |
Liberar o conteúdo para acesso público. info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Liberar o conteúdo para acesso público. |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.coverage.none.fl_str_mv |
|
dc.publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
dc.source.none.fl_str_mv |
reponame:Biblioteca Digital de Teses e Dissertações da USP instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Biblioteca Digital de Teses e Dissertações da USP |
collection |
Biblioteca Digital de Teses e Dissertações da USP |
repository.name.fl_str_mv |
Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
virginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.br |
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1809091206261506048 |