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A performance-prediction theory for partially submerged ventilated propellers

Published online by Cambridge University Press:  20 April 2006

Okitsugu Furuya
Affiliation:
Tetra Tech, Inc., 630 North Rosemead Boulevard, Pasadena, California 91107

Abstract

A partially submerged propeller theory was developed by employing a singularity distribution method. Unsteady pressure doublets and pressure sources represented the blade camber and blade-and-cavity thickness respectively. The induced velocities were derived by reducing the formula to a lifting-line configuration. The free-surface effect was considered by use of the image method. The induced velocities contained the singular integrals of 5th order, which are usually numerical unstable. An effort was made to derive numerically stable formulae from these singular equations by applying a method similar to the induction-factor method of Morgan & Wrench (1965) and Lerbs (1952) used for steady-state fully wetted propeller problems. These new formulae are not only applicable to the present partially submerged ventilated propeller problem, but also to general unsteady subcavitating and cavitating propeller problems such as propeller starting-up and non-periodic loading problems. By combining the two-dimensional water entry-and-exit theory of Wang (1979), the thrust and torque coefficients were calculated for representative partially submerged propellers and favourably compared with the experimental data.

Type
Research Article
Copyright
© 1985 Cambridge University Press

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References

Cox G. G.1968 Supercavitating propeller theory - The deviations of induced velocity. Proc. 7th Symp. on Naval Hydrodynamics, Rome, pp. 929960.
Furuya O.1980 Off-design performance predictive method for supercavitating propellers. Proc. 13th Symp. on Naval Hydrodynamics, Tokyo, pp. II-2-1II-2-24.
Hadler, J. B. & Hecker R.1968 Performance of partially submerged propellers. Proc. 7th Symp. on Naval Hydrodynamics, Rome, pp. 14491496.
Kerwin, J. E. & Leopold R.1963 Propeller-incidence correction due to blade thickness. J. Ship Res. 7, 16.Google Scholar
Lerbs H. W.1952 Modulated loaded propellers with a finite number of blades and an arbitrary distribution of circulation. SNAME Trans. 60, 73123.Google Scholar
Mangler K. W.1951 Improper integrals in theoretical aerodynamics. RAE, Farnborough, Rep. Aero 2424.Google Scholar
Morgan, W. B. & Wrench J. W.1965 Some computational aspects of propeller design. In Methods of Computational Physics, vol. 4, pp. 301331. Academic.
Monacella V. J.1967 On ignoring the singularity in the numerical evaluation of Cauchy principal value integrals. US Navy NSRDC R & D Rep. 2356.Google Scholar
Wang D. P.1977 Water entry and exit of a fully ventilated foil. J. Ship Res. 21, 4468.Google Scholar
Wang D. P.1979 Oblique water entry and exit of a fully ventilated foil. J. Ship Res. 23, 4354.Google Scholar
Yim B. Y.1969 Application of linearized theory to water entry and water exit problems. Part 2. With ventilation. NSRDC Rep. 3171.Google Scholar
Yim B. Y.1971 Investigation of gravity and ventilation effects in water entry of thin foils. Proc. IUTAM Symp. Leningrad.
Yim B. Y.1974 Linear theory on water entry and exit problems of a ventilating thin wedge. J. Ship. Res. 18, 111.Google Scholar