| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| Documento principal | 5.6 MB | Adobe PDF | ||
| AnexoI | 2.29 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
A modelação numérica de veículos terrestres de alta-performance, a baixos números de
Reynolds, sofre de uma falta de precisão normalmente associada ao uso dos modelos
numéricos neste regime de escoamento. Assim, a modelação computacional do escoamento
em torno de veículos neste regime necessita de uma cuidadosa verificação experimental. Por
outro lado o ensaio experimental com recurso a modelos à escala introduz dificuldades
significativas, de modo a garantir as condições de semelhança dinâmica, pelo que em
alternativa podem fazer-se cuidadosamente ensaios à escala real em pista.
Neste trabalho modelamos numericamente o escoamento em torno do corpo simplificado de
Ahmed e do veículo UBIAN10. Este veículo participou em 2010 na competição Shell Ecomarathon
Europe em representação da Universidade da Beira Interior, que decorreu em
Leipzig, na Alemanha.
O cálculo do escoamento em torno do corpo de Ahmed permite analisar a influência da
malha, e do tipo de modelo de turbulência, nos resultados obtidos quando comparados com os
valores experimentais e numéricos disponíveis na literatura. Além dos coeficientes
aerodinâmicos foi ainda feito um estudo sobre a estrutura do escoamento, em particular
sobre a geração de vórtices que ocorre na esteira do corpo de Ahmed. A modelação numérica
do UBIAN10 compreendeu um extenso trabalho de geração de malhas que, de forma iterativa,
permitiu aferir da sua boa qualidade. Em particular, em termos da skewness e da garantia do
y+ junto das fronteiras sólidas. Além do cálculo dos coeficientes aerodinâmicos foi também
feita uma análise à estrutura do escoamento para três configurações diferentes do UBIAN10.
O veículo UBIAN10 foi objecto de um ensaio experimental em pista. Este estudo faz parte de
um conjunto de ensaios experimentais mais extensos que têm sido desenvolvidos pela equipa
do UBIAN10. O ensaio em pista permitiu concluir que os resultados da modelação
computacional tinham uma boa precisão. Com base no conhecimento do escoamento em
torno do UBIAN foi possível redesenhar o veículo tendo vista melhorar o seu desempenho
aerodinâmico.
The numerical modeling of high performance ground vehicles, at low Reynolds numbers, suffers from a lack of precision usually associated with the use of numerical models in this flow regime. Thus, the computational modeling of the flow around vehicles in this regime requires a careful experimental verification. On the other hand, the experimental testing using scaled models introduces significant difficulties, this in order to ensure the conditions of dynamic similarity, in alternative full scale tests can be done on track. In this work we modeled numerically the flow around the simplified Ahmed body and on the UBIAN10 vehicle. This vehicle participated on the 2010 Shell Eco-marathon Europe competition on behalf of University of Beira Interior, held in Leipzig, Germany. The computation of the flow around the Ahmed body allows to analyze the influence of the mesh, and of the type of turbulence model, on the results as compared with available experimental and numerical values in the literature. In addition to the aerodynamic coefficients a study was done on the structure of the flow, in particular on the generation of vortices that occurs in the wake of the Ahmed body. The numerical modeling of UBIAN10 comprised an extensive work of mesh generation that, in an iterative way, allowed the assessment of their quality. In particular, in terms of skewness and ensuring an adequate y+ near solid boundaries. In addition to the computation of the aerodynamic coefficients an analysis of the flow structure was also made for three different configurations of UBIAN10. The UBIAN10 vehicle was subject to an experimental test on the track. This study was a component of a more extensive experimental testing programme developed by UBIAN Team. The track test concluded that the results obtained using computational modeling had a good accuracy. Based on the knowledge of the flow around the UBIAN it was possible to redesign the vehicle in order to improve its aerodynamic performance.
The numerical modeling of high performance ground vehicles, at low Reynolds numbers, suffers from a lack of precision usually associated with the use of numerical models in this flow regime. Thus, the computational modeling of the flow around vehicles in this regime requires a careful experimental verification. On the other hand, the experimental testing using scaled models introduces significant difficulties, this in order to ensure the conditions of dynamic similarity, in alternative full scale tests can be done on track. In this work we modeled numerically the flow around the simplified Ahmed body and on the UBIAN10 vehicle. This vehicle participated on the 2010 Shell Eco-marathon Europe competition on behalf of University of Beira Interior, held in Leipzig, Germany. The computation of the flow around the Ahmed body allows to analyze the influence of the mesh, and of the type of turbulence model, on the results as compared with available experimental and numerical values in the literature. In addition to the aerodynamic coefficients a study was done on the structure of the flow, in particular on the generation of vortices that occurs in the wake of the Ahmed body. The numerical modeling of UBIAN10 comprised an extensive work of mesh generation that, in an iterative way, allowed the assessment of their quality. In particular, in terms of skewness and ensuring an adequate y+ near solid boundaries. In addition to the computation of the aerodynamic coefficients an analysis of the flow structure was also made for three different configurations of UBIAN10. The UBIAN10 vehicle was subject to an experimental test on the track. This study was a component of a more extensive experimental testing programme developed by UBIAN Team. The track test concluded that the results obtained using computational modeling had a good accuracy. Based on the knowledge of the flow around the UBIAN it was possible to redesign the vehicle in order to improve its aerodynamic performance.
Description
Keywords
Veículo automóvel - Aerodinâmica Aerodinâmica de veículos - Evolução histórica Aerodinâmica de veículo - Modelação experimental Mecânica dos fluídos computacional Shell Eco-Marathon Modelação de turbulência
Pedagogical Context
Citation
Publisher
Universidade da Beira Interior