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| Author(s): |
Iago de Carvalho Barbeiro
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Escola Politécnica (EP/BC) |
| Defense date: | 2012-03-06 |
| Examining board members: |
Julio Romano Meneghini;
Bruno Souza Carmo;
José Roberto Castilho Piqueira;
Clodoaldo Grotta Ragazzo;
Alexandre Megiorin Roma
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| Advisor: | Julio Romano Meneghini |
| Abstract | |
This thesis concerns the flow past a cylinder just after its first bifurcation, within its two-dimensional periodic regime. The approach is mainly theoretical, goes through experiments and is concluded by an important numerical part which complements the theory with evidences and illustrations. The main contributions are the analysis concerning the modal composition of the solution within the periodic regime and a method to identify eigenvectors of some linearizaton of the Navier-Stokes equation participating on a given solution. The bases spanned by the identified eigenvectors are employed in the projection of the Navier-Stokes equation and are central to the reduced models of this study. The numerical results for Re = 60 present two iterations of the process, with two bases of dimensions 12 e 24. The reduced models are numerically stable and their integration is many orders less costly than that of the full simulation. The time series of the modal coordinates and the eigenvectors bases allow the recomposition of the flow and its comparison with the full simulation results. The convergence analysis was based on the time averages, the Strouhal number values and the harmonic structure. Both reduced models have close correspondence with the asymptotic behavior of the flow and the convergent trend of the iterations is clear. The space and time symmetries of the harmonics have a simple representation within the structure of the models, therefore the identified bases can be understood as sets of coherent structures of the phenomenon. (AU) | |
| FAPESP's process: | 05/04033-4 - Flow study around two aligned cylinders: numerical simulations and hydrodynamic stability |
| Grantee: | Iago de Carvalho Barbeiro |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |