Loosely supported cylinders subjected to cross-flow may undergo fluidelastic instability in the support inactive mode resulting in cylinder/support impacting. The cylinder/support interaction forces and, in turn, the resulting cylinder wear rates are strongly dependent on the detailed dynamical response. This Thesis examines the response of a loosely supported cylinder located in the third row of an otherwise rigid rotated triangular array. The feasibility and potential of a modern nonlinear dynamics approach to the understanding of the underlying dynamics is investigated. / A nonlinear quasi-steady model was formulated to model the dynamical behaviour. The steady fluid force field, required as input to the model, was measured experimentally for a cylinder within a rotated triangular array. A lither stability analysis showed the cylinder stability behaviour to be strongly dependent on cylinder position. This result serves as a possible explanation for the rare occurrence of, theoretically predicted, multiple instability regions in experimental measurements. / The nonlinear analysis uncovered two important transition routes to chaos. The first, a switching mechanism prevalent at the onset of impacting. The second and most important is the intermittency route to chaos. The theoretical model showed good agreement with experiments in predicting the bifurcation sequences and transitions to chaos--comparisons were quantified via fractal dimensions and saddle orbit distributions. / The identification of type I intermittency leads to a quantitative estimate of the probability distribution of the length of laminar phases. It is shown that the duration of laminar phases and the associated frequency may provide better estimates of integration time and frequency for wear-rate computation.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.41228 |
| Date | January 1993 |
| Creators | Mureithi, Njuki W. |
| Contributors | Price, S. J. (advisor), Paidousis, M. P. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Mechanical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001358543, proquestno: NN91705, Theses scanned by UMI/ProQuest. |
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