Agradecimentos: The authors are indebted to Dr. Jean-Philippe Laval, who provided the MFLOPS3D code used in the present work. The authors gratefully acknowledge the partial support for this research provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq, under the Research...

Agradecimentos: The authors are indebted to Dr. Jean-Philippe Laval, who provided the MFLOPS3D code used in the present work. The authors gratefully acknowledge the partial support for this research provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq, under the Research Grants with Nos. 309985/2013-7 and 470695/2013-7. The work was also supported by Fundação de Amparo à Pesquisa do Estado de São Paulo, FAPESP, under the Research Grants with Nos. 2013/03413-4, 2013/07375-0 and 2014/07623-6. Further acknowledgment is due to Fundação Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES, for the doctoral scholarship for the first author. The computational resources provided by Centro Nacional de Supercomputação, CESUP, and by Centro Nacional de Processamento de Alto Desempenho, CENAPAD-SP, are also gratefully acknowledged

The paper is focused on the study of fully turbulent channel flows, using Large Eddy Simulations (LES), in order to address the effects of adverse pressure gradient regions. Analyses of the effects of streak instabilities, which have been shown to be relevant in such regions, are extended to...

The paper is focused on the study of fully turbulent channel flows, using Large Eddy Simulations (LES), in order to address the effects of adverse pressure gradient regions. Analyses of the effects of streak instabilities, which have been shown to be relevant in such regions, are extended to moderate Reynolds numbers. The work considers two different channel geometries in order to further separate influences from wall curvature, flow separation and adverse pressure gradients. Turbulent kinetic energy and Reynolds stress budgets are investigated at separation and re-attachment points. The numerical approach used in the present work is based on the incompressible Navier–Stokes equations, which are solved by a pseudo-spectral methodology for structured grids. Wall-resolved LES calculations are performed using the WALE subgrid scale model. The study shows that the streak instability mechanism persists at higher Reynolds numbers with and without wall curvature in the adverse pressure gradient regions. Moreover, the observed effects are also present regardless of the existence of flow separation regions. Finally, the study of turbulent kinetic energy budgets indicates that, independently of the flow condition, there are well-defined patterns for such turbulent properties at separation and re-attachment points

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ

309985/2013-7; 470695/2013-7

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP

2013/03413-4; 2013/07375-0; 2014/07623-6

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