Springing of ships waves

Title

Springing of ships waves

 Author

Van Gunsteren, F.F.

Contributor

Gerritsma, J. (promotor)

Faculty

Mechanical, Maritime and Materials Engineering

 Date

1978-11-09

 Abstract

This thesis is the result of an investigation of the assumptions underlying the general applied method for the calculation of springing of ships in waves, which has been proposed by the author some decade ago. It has been found that, contrary to the general practice in seakeeping research, the frequency response method can not be applied for the determination of the springing response to random wave loading. Other assumptions regarding the hydrodynamic springing excitation and 2-node vertical main hull response have been confirmed. - In moderate sea states springing is linear with respect to wave height. - The longitudinal distribution of the damping may be assumed to be proportional to the distribution of the mass, the stiffness or a combination of them. The normal mode method can therefore be applied. - All hydrodynamic forces due to the vibration of the ship should be taken into account, i.e. vibratory induced buoyancy, as well as damping and mass forces cannot be neglected. Uncertainties in the springing calculation method have been described: - the damping coefficient of the 2-node vertical vibration and its longitudinal distribution - the applicability of the present striptheory for the calculation of the distribution of wave exciting forces along the length of the ship in relatively short waves - the parameters associated with the correction to the frequency response method for the calculation of the springing response to random wave loading. The conclusions are based on results of analysis of full scale as well as model experiments, theoretical calculations and time domain computer simulations. Finally, a method is presented to account for the deficiencies in the frequency response method in the calculation of springing of ships in waves.

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 Part of collection

Institutional Repository

 Document type

doctoral thesis

 Rights

(c) 1978 Van Gunsteren, F.F.
Files
PDF P_1784_4434.PDF 47.8 MB
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