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Design Optimization of Axi-symmetric Tail Tube Buoys

  • T. J. T. Whittaker
  • F. A. McPeake
Conference paper
Part of the International Union of Theoretical and Applied Mechanics book series (IUTAM)

Summary

This paper presents the results of an experimental test programme and theoretical analysis of the hydrodynamic design of wave powered axi-symmetric navigation buoys. A two degree of freedom system with power extraction damping the relative motion of the two heave modes is considered. Results are presented for a theoretical model which has been verified experimentally.

It is concluded that the power extraction efficiency and frequency bandwidth of the current design of wave powered. navigation buoy can be considerably improved. Peak capture factor increases proportionally with the tube diameter for tube / buoy diameter ratios of up to 75%. Increased tube length widens the frequency bandwidth response. The level of applied damping has considerable effect on peak performance and frequency bandwidth response. With this two degree of freedom system, the levels of applied damping which produce maximum capture factor are approximately 20 times greater than the optimum values for the isolated water columns. Also the radiation damping associated with the two heave modes should be similar so that the damping applied by the power extraction system is matched at both natural response frequencies. The work has general application to the design of wave powered buoys with a central cylindrical water column.

Keywords

Peak Performance Irish Light Wave Tank Power Extraction Heave Motion 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notation

B

radiation dampng.

Ba

applied damping; (turbine damping.)

Bab

optimum applied damping at water column resonance.

C

damping ratio; Ba/Bab.

D

non dimensional radiation damping.

F

wave excitation force.

k

buoyancy.

L

tail tube length from water line.

Ma

added mass, (dynamic.)

Ms

mass, (static.)

R

buoy hull radius.

r

tail tube radius.

x

displacement from equilibrium position.

ρ

water density.

ω

frequency in radians.

Suffix b.

refers to the buoy hull.

Suffix w.

refers to the water column.

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References

  1. 1.
    Whittaker, T.J.T., McPeake,F.A., Barr,A.G., The Development and Testing of a Wave Activated Navigation Buoy with a Wells Turbine. 3rd Int. Symp. on Offshore Mechanics and Engineering, New Orleans, LA, USA, Feb. 12–16, 1984, pp 267–273, Vol 2.Google Scholar
  2. 2.
    Masuda,Y. Wave Activated Generator. Int. Coll. on the Exploitation of the Oceans. (Trans.). Bordeaux, France 1971.Google Scholar
  3. 3.
    Whittaker,T.J.T., McIlhagger,D.S., Barr,A.G., Wells Turbines for Navigation Buoys. 3rd. Int. Conf. Energy for Rural and Island Communities. Inverness. Scotland Sept. 12–16, 1983, PP 289–297.Google Scholar
  4. 4.
    Whittaker,T.J.T., McIlhagger,D.S., Barr,A.G., THompson,A., Electrical Considerations with Wave Powered Navigation Aids Conf. Alternative Energy Systems: Elect. Integration and Utilisation. Coventry. U.K. Sept. 10–12.Google Scholar
  5. 5.
    Whittaker,T.J.T., Murray,M.A., Performance Characteristics of Hydropneumatic Buoys in Line Array. Proc. Int. Symp. on Hydrodynamics, Ocean Eng., Trondheim, 1981. pp 1047–1066.Google Scholar
  6. 6.
    Evans,D.V., Mclver,P., The Hydrodynamical Characteristics of a Section of a Floating Sphere Making Vertical Oscillations. School of Mathematics University of Bristol. Report AM-82–09Google Scholar

Copyright information

© Springer-Verlag Berlin, Heidelberg 1986

Authors and Affiliations

  • T. J. T. Whittaker
    • 1
  • F. A. McPeake
    • 1
  1. 1.Dept. of Civil EngineeringThe Queen’s University of BelfastBelfastN. Ireland

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