Numerical and experimental modelling of ship resistance in compressive ice channels

Abstract

The effect of compressive ice fields on ships has been a research topic for a few decades, but still the knowledge is limited on this subject.

In this thesis the ship resistance in compressive ice channels has been studied. The motivation to undertake this research comes from a need to find and assess simple methods for estimating the resistance of vessels in compressive ice situations and for using them in a traffic ability model. The need for simple methods comes from the fact that the specific knowledge about vessels visiting the Baltic Sea is limited.

The presented calculation methods are evaluated by using model testing data which was gathered during the SAFEWIN project's model tests. Additional model tests were conducted as a part of this thesis for checking some of the assumptions made based on the first tests. An unexpected resistance component was discovered through the additional tests. A possible explanation and estimation method for evaluating this component is presented and analysed.

A combined formula for evaluating the different resistance components assumed to be affecting the model in the model testing is presented. The results show that the general principals and methods used for calculating combined resistances give fairly accurate results.