Ship resistance in ice floe covered waters

Aboul-Azm, Azmy Fouad (1989) Ship resistance in ice floe covered waters. Doctoral (PhD) thesis, Memorial University of Newfoundland.

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Abstract

The developmemt of new analytical and numerical methods for the calculation of ship resistance in broken, pack icef or ice floe covered waters, as well as full scale and model testing, has been addressed in this dissertation. -- In this study three methods for the calculation of ship resistance are presented. The first analytical formulation of ship resistance in ice fragments (The Micro Model) is based on the calculation of energy loss due to an impact between an advancing ship and an ice floe. Based on The Kinetic Theory of Gases (molecule collision and pressure) the number of possible ice floes colliding with the ship, in a given time, was estimated and consequently total ship energy loss and ship resistance was determined. The second approach for the calculation of ship resistance due to ice floes (The Macro Model) was formulated and developed based on the analysis of water drag of displaced ice floes. The Macro Model is based on the prediction of the total forces acting on the ship as a result of the displacement of a large number of ice floes out of the ship's path. -- Both analytical models have been formulated to account for both the ship characteristics and ice cover properties. Numerical calculations of ship resistance for existing ship hull forms have been performed and presented, in this study, using the newly developed models. -- A numerical calculation method based on the distinct element method has been introduced in this dissertation as a new approach for the calculation of ship resistance in ice floe or pack ice. -- Besides the analytical and the numerical approaches developed, a number of model test experiments were conducted in simulated broken ice cover to measure ship resistance increase due to ice fragments. -- A Full-Scale field measurement program was beyond the scope of this study. However, results from existing full scale tests, available in the literature, have been collected, analysed and presented in this study. -- Results from the new analytical and numerical models, model test experiments, and full scale field measurements, have been presented in this study to verify the validity of the different approaches. -- This study has developed new methods or tools for calculating the ship resistance in broken ice. This study has shown that it is possible to predict with reasonable accuracy, the magnitude of ship resistance in a given ice floe or pack ice cover.

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