Wave induced motion of small ice masses

Abstract

Experiments have been performed to assess the ability of linear diffraction theory to predict the motion of ice masses under wave excitation. Variables in the regular wave portion of the experiment included iceberg size and shape and wave steepness. Regular wave tests demonstrated accurate motion prediction, with best results achieved for smooth sided bodies undergoing small amplitude motion. Accuracy was lower for low frequency surge and heave resonance results, and generally for bodies with steeply sloping sides. -- Irregular tests were performed to demonstrate the ability to predict motion in an irregular seaway. It was seen that by combining response amplitude operators (RAO's) with wave spectra, response spectra for individual bodies could be predicted. The predicted spectra generated using experimentally determined RAO's very accurately mirrored the ones generated by transforming irregular-wave body response data to the frequency domain. Predicted spectra generated using theoretically determined RAO's were studied as well. It was found that the accuracy of such spectra was directly tied to the accuracy of the associated RAO's.