Experiments on perturbed Saffman-Taylor flows
[eng] We have performed pattern formation experiments where a relatively well understood system (flow in a Hele-Shaw cell) is perturbed either by means of a lattice of grooves or by the use of viscoelastic fluids. We have extended the qualitative analysis found in the literature for anisotropic fing...
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| Formato: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 1997 |
| País: | España |
| Recursos: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/187803 |
| Acesso em linha: | https://hdl.handle.net/2445/187803 http://hdl.handle.net/10803/674811 |
| Access Level: | acceso abierto |
| Palavra-chave: | Dinàmica de fluids Pertorbació (Dinàmica quàntica) Fluid dynamics Perturbation (Quantum dynamics) |
| Resumo: | [eng] We have performed pattern formation experiments where a relatively well understood system (flow in a Hele-Shaw cell) is perturbed either by means of a lattice of grooves or by the use of viscoelastic fluids. We have extended the qualitative analysis found in the literature for anisotropic fingering patterns, presenting a more quantitative approach that may prove useful as a tool to attack more complex problems. We have analyzed the different morphological regimes and looked for signatures of the transition between phases, with partial success when we try to characterize a given morphology quantitatively. In our studies of viscoelastic Hele-Shaw flow with associative polymer solutions, we have observed a transition from viscous fingering patterns into a regime where the growing patterns resemble the fracture in brittle solids. We have been able to rescale the threshold for these transitions, and we have observed interesting properties in a regime of fracturelike patterns where, under sorne circumstances, we have measured a characteristic oscillation frequency which shows interesting regularities. We have also studied the pressure in the viscoelastic flow, and found consistent results that may be used to implement a better theoretical model to fully understand the dynamics. |
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