An investigation into the static and dynamic swell up effect effect for ship motions

Squires, Michael Anthony (1992) An investigation into the static and dynamic swell up effect effect for ship motions. University of Southampton, Doctoral Thesis.

Abstract

This thesis details the investigation into the factors affecting deck wetness of ships. The two factors of prime concern are the static swell up phenomenon and the dynamic swell up coefficient. The static swell up may be loosely described as the effect of the ships steady forward motion on its freeboard. The dynamic swell up coefficient may be described as a factor accounting for the effect of radiated and diffracted waves on the ship-wave relative motion. The static swell up phenomenon has been investigated theoretically using the Neuman-Kelvin method. This is a singularity distribution method and is based on Kelvin sources at the centre of panels distributed over the hull surface. The static swell up phenomenon has also been investigated using model experiments. The dynamic swell up coefficient and three component dynamic swell up coefficients, based on heave radiation, pitch radiation and diffraction, have been calculated using a theoretical method. This method was based on the use of translating pulsating source panels distributed in a similar manner to the source panel technique for the Neuman-Kelvin problem. The dynamic swell up coefficients have also been measured using model experiments. A novel experimental method was devised in order to measure the three component dynamic swell up coefficients. Comparisons have been made between the experimental and theoretical results and it has been concluded that the dynamic swell up coefficients can be calculated using a three dimensional singularity distribution technique. The variation of the dynamic swell up coefficients with position, incident wavelength and model speed has also been investigated. Further, the convergence of the theoretical results with number of panels in the longitudinal direction has been discussed with reference to the wavelengths of the translating pulsating source wave system. Finally the effect of the models steady motion on the theoretical dynamic swell up coefficients has been investigated.

This record has no associated files available for download.

Contributors

Download statistics