This thesis contains an experimental campaign on the practical implementation of
oscillating-foil technologies. It explores two possible engineering applications of
oscillating-wings: thrust-generation, and energy-extraction. The history of, benefits of,
and difficulties involved in the use of oscillating-foils is discussed throughout. Many
existing technologies used for thrust generation and hydrokinetic energy extraction are
based on rotating blades or foils, which have evolved over decades of use. In recent
years, designs that use oscillating-foils, with motions analogous to the flapping of a
fish’s tail or a bird’s wing, have shown increased hydrodynamic performance compared
to the traditional rotary technologies. However, these systems are complex, both in
terms of the governing unsteady fluid dynamics, and the methods by which kinematics
are prescribed. Simply put, system complexity and cost need to be reduced before
these devices see wide-spread use. For this reason, the work contained within this
thesis explores possible methods of reducing the complexity of oscillating-foil systems
in an effort to contribute to their development. For thrust-generation applications, this
entailed using flexible foils to create passive pitching kinematics. This was
parametrically studied by testing foils of different structural properties under a range of
kinematics. The results suggested that properly tuning the flexibility of the foil could
enhance both the thrust generation, and the efficiency of the propulsive system. With
respect to energy-harvesting applications, the reliability of a novel fully passive turbine
was assessed. The prototype tested had no active control strategy, and the degreesof-freedom
were not mechanically linked, greatly simplifying the design. The prototype
was subjected to real-world conditions, including high turbulence levels and the wake
of an upstream turbine, and displayed robust performance in most conditions. In both
applications, the hydrodynamic performance of the oscillating-wings was directly
measured, and particle image velocimetry was used to observe the flow topology in the
wakes and boundary layers of the foils. The vortex and stall dynamics were highlighted
as key flow features, and are studied in detail. / Graduate
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/10124 |
| Date | 01 October 2018 |
| Creators | Iverson, Dylan |
| Contributors | Oshkai, Peter, Dumas, Guy |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
| Rights | Available to the World Wide Web |
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