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Previous issue date: 2018-03-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / This work investigates the method of large-eddy simulation (LES) in the context
of gravity currents, which is found necessary since it allows a substantial increase
in the order of magnitude of the characteristic Reynolds number used in numerical
simulations, approaching them with natural scales, in addition to significantly reducing
the computational cost. The implicit large eddy simulation (ILES) methodology, based
on the spectral vanishing viscosity model, is unprecedentedly employed in the context
of gravity currents, is compared against with explicit methods such as the static and
dynamic Smagorisnky. The evaluation of the models is performed based on statistics
from a direct numerical simulation (DNS). Results demonstrate that the first model
based purely on numerical dissipation, introduced by means of the second order
derivative, generates better correlations with the direct simulation. Finally, experimental
cases of the literature, in different flow configurations, are reproduced numerically
showing good agreement in terms of the front position evolution. / Este trabalho investiga o m?todo de simula??o de grandes escalas (LES) no
contexto de correntes gravitacionais. O mesmo se faz necess?rio, visto que possibilita
um aumento substancial da ordem de grandeza do n?mero de Reynolds caracter?stico
utilizado em simula??es num?ricas, aproximando os mesmos de escalas naturais, al?m
de reduzir significativamente o custo computacional dos c?lculos. A avalia??o dos
modelos ? realizada utilizando uma base de dados de simula??o num?rica direta (DNS).
A metodologia de simula??o de grandes escalas impl?cita (ILES), baseada no modelo
de viscosidade turbulenta espectral, ? colocado a prova de maneira in?dita no contexto
de correntes de gravidade com m?todos expl?citos dispon?veis na literatura. Resultados
demonstram que o mesmo, baseado puramente em dissipa??o num?rica introduzida
por meio do comportamento dos esquemas de derivada de segunda ordem, gera
melhores correla??es com as estat?sticas baseadas em campos m?dios da simula??o
direta. Por fim, casos experimentais da literatura, em diferentes configura??es de
escoamento, s?o reproduzidos numericamente.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/8127 |
| Date | 09 March 2018 |
| Creators | Frantz, Ricardo Andr? Schuh |
| Contributors | Silvestrini, Jorge Hugo |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Engenharia e Tecnologia de Materiais, PUCRS, Brasil, Escola Polit?cnica |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -7432719344215120122, 500, 500, 600, 4518971056484826825, 2075167498588264571 |
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