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| Author(s): |
Guilherme Rosa Franzini
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: | 2012-12-13 |
| Examining board members: |
André Luís Condino Fujarra;
Gustavo Roque da Silva Assi;
Luis Fernando Alzuguir Azevedo;
Antonio Carlos Fernandes;
Celso Pupo Pesce
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| Advisor: | André Luís Condino Fujarra |
| Abstract | |
The flow around yawed cylinders, or oblique flow, is a common subject in several engineering applications. Despite the flow around a non-yawed cylinder consists on a classical and extensively investigated problem, there is a considerable lower number of investigation concerning the oblique flow. The most employed approach aiming at investigating the oblique flow is the so called Independence Principle, which states that the flow characteristics depend only on the component of the free-stream that is normal to the cylinder axis. Three groups of experiments were carried out aiming at a better understanding of the flow around yawed cylinders. Five yaw angles defined between the cylinder axis and the direction orthogonal to the free-steam were tested, namely: theta = 0°, 10°, 20°, 30° e 45°. From the first group of experiments, the results obtained with stationary cylinders yawed in the upstream orientation shown that the mean drag coeficient matches the classical results from the non-yawed cylinder, if the component of the free-stream that is orthogonal to the cylinder axis is employed in the normalization of the hydrodynamic force. Concerning vortex-induced vibrations experiments with one and two degrees-of-freedom, a decrease was observed in the maximum oscillation amplitude. For all the experiments, it was observed that the results obtained from the upstream orientation tests can be different from those obtained for the downstream orientation ones. The larger the yaw angle, the larger are the differences, which are associated to the asymmetric end conditions. (AU) | |
| FAPESP's process: | 08/00688-4 - Investigation on VIV phenomenon of flexible cylinders |
| Grantee: | Guilherme Rosa Franzini |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |