Vortex-Structure Interaction

Blevins, Robert D.

doi:10.1007/978-94-011-0249-0_12

Cited by 5 publications

(8 citation statements)

References 85 publications

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“…Resonance was not continuous across the entire velocity range studied but occurred in bursts across specific velocity ranges and generally increased in magnitude as velocity increased. This behaviour is consistent with generally accepted norms 3 for vortex induced structural resonance. The study also discussed the possible role of the relative positioning of the lower paddle grip and central resonance node in the damping of unwanted paddle resonance.…”

Section: Introductionsupporting

confidence: 91%

“…2 The resulting vibrations can in turn strengthen further vortex generation, thereby increasing drag on the paddle blade by as much as a factor of three. 3 Increased resistance to the water movement over the blade will be directed against the direction of canoe progress and therefore will reduce overall canoeing efficiency. Interestingly, the best quality paddles do not usually induce vibrations and, therefore, avoid the penalty of increased resistance to paddle blade movement.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of the resonance behaviour of ottertail and voyageur style canoe paddles during the J-stroke

Runciman

Lyle

2012

Proceedings of the Institution of Mechanical Engineers, Part P:

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The canoe paddle has immense cultural and historical significance. Recognized throughout the world, the paddle has remained largely unchanged since its inception thousands of years ago. A major characteristic of performance in a recreational canoe paddle, and one that distinguishes a good paddle from a bad one, involves its tendency to resonate during use. With paddle resonance comes increased fluid resistance and a less efficient stroke. This study compared resonance tendencies of two major types of recreational canoe paddles, the ottertail and voyageur styles, in stiff and flexible formats. Data was acquired during open water canoe use and canoe velocities up to 2.0 m/s During testing two 3-axis accelerometers were mounted on the shaft of the subject paddle. These accelerometers were then connected to onboard data collection instrumentation to record paddle resonance behaviour. Concurrent GPS-based canoe velocities were also recorded. The conventional J-stroke was used for all testing, and the canoe was repeatedly paddled between known points spaced approximately 100 m apart. Fluid driven resonance was observed at two specific phases of the J-stroke, the beginning of the control phase and the beginning of the recovery phase. The magnitude and characteristics of paddle resonance varied with the specific phase of the stroke, canoe paddle stiffness, style and velocity. The combination of these factors that resulted in the lowest paddle resonance of the combinations studied was a flexible ottertail style paddle, being paddled in the range of 1–1.8 m/s.

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Section: Introductionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Comparison of the resonance behaviour of ottertail and voyageur style canoe paddles during the J-stroke

Runciman

Lyle

2012

Proceedings of the Institution of Mechanical Engineers, Part P:

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“…These paddle vibrations are so common in the sport of canoeing that they have been given a name: a paddle’s song. These vibrations affect the flow properties adjacent to the paddle blade, thereby increasing drag on the paddle blade by as much as a factor of three [7]. The best quality paddles do not induce vibrations and therefore avoid the penalty of increased resistance to blade movement.…”

Section: Introductionmentioning

confidence: 99%

“…In examining the literature pertaining to fluid-flow-induced vibrations it is clear that research into the relationship between structural vibrations and fluid flow has remained primarily in the experimental realm [7–9]. Some limited success has been achieved by Caplan et al .…”

Section: Introductionmentioning

confidence: 99%

“…This rolling of the fluid results in a regular and oscillating pattern of vortices being formed adjacent to the trailing edge of the blade. From research in the field, it is known that the approximate frequency of these vortices is proportional to the blade to free stream fluid relative velocity, and inversely proportional to blade thickness [7]. These oscillating vortices impart oscillating loads on the blade which drive the vibrations in the paddle.…”

Section: Introductionmentioning

confidence: 99%

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Canoe paddle resonance characteristics and modelling

Runciman

Lyle

Patrick

2011

Proceedings of the Institution of Mechanical Engineers, Part P:

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Canoe paddles have been in continuous use for thousands of years. Over that period, the paddle has remained virtually unchanged in basic form and materials. Today, paddles are produced in many different designs by a large number of manufacturers. Prominent within the many factors differentiating the best paddles from the worst is their propensity to resonate during use. This resonance has been so prevalent historically that it has been given its own name: a paddle’s song. The major drawback with paddle resonance is that it is accompanied with the penalty of increased fluid resistance. Paddle manufacturers have long tried to reduce or eliminate paddle resonance, but it is still recognized by paddlers as a significant factor in choosing an optimal paddle. This study examined canoe paddle resonance in laboratory, open water, and computer modelling environments. The goal was to investigate the characteristics of this commonly occurring phenomenon and validate the techniques used in the modelling studies. The hypothesis tested in this paper is that by employing and comparing scientific measurement and modelling techniques it would prove possible to examine the relationship between physical paddle structure, fluid-based excitation, and resonance observed during paddle use. The obtained results indicated that the paddle being studied displayed a number of different characteristic resonance patterns or modes depending on the velocity of water flow over the blade. The results of the computer modelling studies on the resonance modes were found to be in good agreement with the observations made in laboratory and open water experiments.

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Implicit multigrid computation of unsteady flows past cylinders of square cross-section

Caughey

2001

Computers & Fluids

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Vortex-Structure Interaction

Cited by 5 publications

References 85 publications

Comparison of the resonance behaviour of ottertail and voyageur style canoe paddles during the J-stroke

Comparison of the resonance behaviour of ottertail and voyageur style canoe paddles during the J-stroke

Canoe paddle resonance characteristics and modelling

Implicit multigrid computation of unsteady flows past cylinders of square cross-section

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