| Texto completo | |
| Autor(es): |
Número total de Autores: 3
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| Afiliação do(s) autor(es): | [1] Inst Tecnol Aeronaut, Div Engn Aerosp, Sao Jose Dos Campos, SP - Brazil
[2] Inst Tecnol Aeronaut, Div Ciencias Fundamentais, Sao Jose Dos Campos, SP - Brazil
[3] Monash Univ, Dept Mech & Aerosp Engn, Lab Turbulence Res Aerosp & Combust, Clayton, Vic - Australia
Número total de Afiliações: 3
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| Tipo de documento: | Artigo Científico |
| Fonte: | JOURNAL OF FLUID MECHANICS; v. 932, DEC 14 2021. |
| Citações Web of Science: | 0 |
| Resumo | |
The present work studies the nonlinear dynamics of a shear layer, driven by a body force and confined between parallel walls, a simplified setting to study transitional and turbulent shear layers. It was introduced by Nogueira \& Cavalieri (J. Fluid Mech., vol. 907, 2021, A32), and is here studied using a reduced-order model based on a Galerkin projection of the Navier-Stokes system. By considering a confined shear layer with free-slip boundary conditions on the walls, periodic boundary conditions in streamwise and spanwise directions may be used, simplifying the system and enabling the use of methods of dynamical systems theory. A basis of eight modes is used in the Galerkin projection, representing the mean flow, Kelvin-Helmholtz vortices, rolls, streaks and oblique waves, structures observed in the cited work, and also present in shear layers and jets. A dynamical system is obtained, and its transition to chaos is studied. Increasing Reynolds number Re leads to pitchfork and Hopf bifurcations, and the latter leads to a limit cycle with amplitude modulation of vortices, as in the direct numerical simulations by Nogueira \& Cavalieri. Further increase of Re leads to the appearance of a chaotic saddle, followed by the emergence of quasi-periodic and chaotic attractors. The chaotic attractors suffer a merging crisis for higher Re, leading to a chaotic dynamics with amplitude modulation and phase jumps of vortices. This is reminiscent of observations of coherent structures in turbulent jets, suggesting that the model represents a dynamics consistent with features of shear layers and jets. (AU) | |
| Processo FAPESP: | 19/27655-3 - Modelagem de ordem reduzida para controle em aerodinâmica e aeroacústica |
| Beneficiário: | André Valdetaro Gomes Cavalieri |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |