International Shipbuilding Progress - Volume 5, issue 44

Authors: Naerlovich, Natalija

Article Type: Research Article

Abstract: The paper presents a numerical method for determining vertical forced vibrations of ships’ hulls. The method consists in substituting for the integral equation of forced vibrations a system of linear algebraic equations. The method is compared with that given by A.N. Krylov [1], which is based on the numerical integration of the differential equation of forced vibrations.

DOI: 10.3233/ISP-1958-54401

Citation: International Shipbuilding Progress, vol. 5, no. 44, pp. 151-162, 1958

Authors: Baier, L.A.

Article Type: Research Article

DOI: 10.3233/ISP-1958-54402

Citation: International Shipbuilding Progress, vol. 5, no. 44, pp. 163-165, 1958

Authors: Hunziker, Raul R.

Article Type: Research Article

Abstract: The hydrodynamic interference of a hull-propeller combination moving at a great depth under the free surface is analyzed. On the basis of Oseen’s form of the motion equations, Euler’s theorem and Lagally’s exterior theorem (1922) for a potential stream with singularities a general formula for the thrust deduction fraction is derived. It is shown that the corresponding velocity field contains a system of helical vortices shed by a propeller of an infinite number of blades. In the limiting case of very light loading, the thrust deduction expression is reduced to a generalization of Fresenius’ expression (1921). Numerical values …for different configurations of a prolate ellipsoid hull and propeller are presented in tabular form. The results indicate that the thrust deduction fraction exhibits a rapid diminution with the increase of the distance of the propeller from the stern and with the increase of the propeller diameter. These theoretical results are in complete agreement with experimental values measured by Weitbrecht (1941). Show more

DOI: 10.3233/ISP-1958-54403

Citation: International Shipbuilding Progress, vol. 5, no. 44, pp. 166-177, 1958

Authors: Johnson, A.J. | Ayling, P.W.

Article Type: Research Article

Abstract: The paper is concerned with the presentation of ship-vibration data in a form aimed at enabling quick estimates of frequencies to be made at the design stage. The subject matter represents one aspect of a comprehensive programme of work on ship vibration being carried out by the British Shipbuilding Research Association. Previously published methods have been adapted for this purpose, but in the light of further experimental results obtained by the Authors, it has been possible to extend these methods and suggest certain modifications intended to improve the accuracy of the estimates. Detailed consideration is given to the …flexural rigidity of ships having deck-houses. On the basis of a recently published method for estimating the distribution of longitudinal stresses in deck-houses, a series of calculations was carried out for a wide range of ships in order to derive graphs from which inertia correction factors can be readily obtained. Examples are given illustrating the derivation and use of these factors. Show more

DOI: 10.3233/ISP-1958-54404

Citation: International Shipbuilding Progress, vol. 5, no. 44, pp. 178-197, 1958