Damping of Regular Waves in Model Ice

Abstract

Wave characteristics change significantly when the waves propagate in a solid ice field. The damping of the incident waves due to the presence of the ice sheet has a significant impact on the modification of wave propagation and dispersion. In this study the interaction of waves with solid ice are investigated by means of model tests. The objective of the study is to measure wave and ice characteristics and analyze the data regarding wave damping and the change of wave parameters in model ice. The experiments were performed in the ice tank of the Hamburg ship model basin (HSVA) with a set of regular waves with varying wave number and steepness. The surface elevation of the waves is recorded by acoustic and motion capturing measurement devices. By comparing the measurements of the incident open water waves with the waves in ice, the change in terms of wave amplitude and dispersion due to the presence of ice is analyzed. It is shown that once the waves travels through the ice the angular frequency remains unchanged while the wave amplitude exponentially decays, with an increasing decay coefficient at smaller wave length. Furthermore, the dispersion relation in ice, represented by the measured angular frequency and wave number, is consistent with the theoretical dispersion relation.