Hydrodynamic Characteristics of Weis–Fogh Type Ship-s Propulsion Mechanism Having Elastic Wing

This experiment was conducted in attempt of improving hydrodynamic efficiency of the propulsion mechanism by installing a spring to the wing so that the opening angle of the wing in one stroke can be changed automatically, compared to the existing method of fixed maximum opening angle in Weis-Fogh type ship propulsion mechanism. Average thrust coefficient was almost fixed with all velocity ratio with the prototype, but with the spring type, thrust coefficient increased sharply as velocity ratio increased. Average propulsive efficiency was larger with bigger opening angle in the prototype, but in the spring type, the one with smaller spring coefficient had larger value. In the range over 1.0 in velocity ratio where big thrust can be generated, spring type had more than twice of propulsive efficiency increase compared to the prototype.

Authors:

• K. D. Ro
• J. T. Park
• J. H. Kim

Keywords:

• Hydraulic Machine
• Propulsion Mechanism
• FluidForce
• Elastic Wing.

References:

[1] Weis-Fogh, T., "Quick Estimates of Flight Fitness in Hovering Animals,
Including Novel Mechanism for Lift Production", Journal of
Experimental Biology, Vol.59, pp.169-230, 1973.
[2] Lighthill, M. J., "On the Weis-Fogh Mechanism of Lift Generation",
Journal of Fluid Mechanics, Vol.60, Part 1, pp.1-17, 1973.
[3] Maxworthy, T., "Experiments on the Weis-Fogh Mechanism of Lift
Generation by Insects in Hovering Flight. Part 1. Dynamics of the 'Fling'",
Journal of Fluid Mechanics, Vol.93, pp.47-63, 1979.
[4] Edwards, R. H. and Cheng, H. K., "The Separation Vortex in the
Weis-Fogh Circulation-Generation Mechanism", Journal of Fluid
Mechanics, Vol.120, pp. 463-473, 1982.
[5] Spedding, G. R. and Maxworthy, T., "The Generation of Circulation and
Lift in a Rigid Two-Dimensional Fling", Journal of Fluid Mechanics,
Vol.165, pp.247-272, 1986.
[6] Ro, K. D. and Tsutahara. M., "Numerical Analysis of Unsteady Flow in
the Weis-Fogh Mechanism by the 3D Discrete Vortex Method with GRAPE3A", Transactions of the ASME, Journal of Fluids Engineering,
Vol.119 pp.96-102, 1997.
[7] Zhang Shesheng, et, "Research and progress of Weis-Fogh mechanism
hydrodynamics", Journal of Hydrodynamics, Vol.3, pp.55-60, 1999.
[8] Furber, S. B. and Ffowcs Williams, J. E., "Is the Weis-Fogh Principle
Exploitable in Turbomachinary?", Journal of Fluid Mechanics, Vol.94,
Part 3, pp.519-540, 1979.
[9] Tsutahara, M. and Kimura, T., "An Application of the Weis-Fogh
Mechanism to Ship Propulsion", Transactions of the ASME, Journal of
Fluids Engineering, Vol. 109, pp. 107-113, 1987.
[10] Tsutahara, M. and Kimura, T., "A Pilot Pump using the Weis-Fogh
Mechanism and its Characteristics", Transactions of the JSME, Vol.54,
No.498, pp.393-397, 1987.
[11] Tsutahara, M. and Kimura, T., "Study of a Fan Using the Weis-Fogh
Mechanism (An Experimental Fan and Its Characteristics)",
Transactions of the JSME, Vol.60, No.571, pp.910-915, 1994.
[12] Zhang S. S., "Hydrodynamic model of Weis-Fogh mechanism hydrofoil",
Journal of Hydrodynamics, Vol.4. pp.35-39, 1996.
[13] Ro, K. D., Kim, K. S. and Kim, J. H., "The Flow Characteristics around
Airfoil Moving Reciprocally in a Channel", Transactions of the KSME,
Vol.32, No.7, pp. 536-541, 2008(in Korean).
[14] K. D. Ro, B. S. Zhu and H. K. Kang, "Numerical Analysis of Unsteady
Viscous Flow Through a Weis-Fogh Type Ship Propulsion Mechanism
Using the Advanced Vortex Method", Transactions of the ASME, Journal
of Fluids Engineering, Vol. 128, pp.481-487, 2006.