Different Ways of Modeling Ice Drift Scenarios in Basin Tests

One known scenario from full scale sea ice investigations is a drifting managed ice field. This ice field may be driven by winds or currents or both and may eventually hit a vessel or an offshore structure. In case of a moving vessel the relative motion between vessel and ice may be determined by the vessels direction of motion or even its ambition to hold position against the drifting ice. All the above described scenarios deal with relative motions between several bodies. Along with the relative motion come the contact forces between the interacting bodies and last but not least the question of the failure of either of the bodies. As ice model tests are in general state of the art procedures to investigate the behavior of a vessel and the related loads in sea ice the question of how to model drift scenarios is of relevance here. Typically in ice model tests a drifting managed ice field is simulated by moving a model ship through a resting ice field. This paper addresses the differences in modeling the ice drift as described above and when moving the floes against a stationary vessel. For this purpose ice model tests of each kind are investigated and theoretical efforts are made to enlighten the topic. Also it is distinguished between the vessel being driven by its own propulsion system or by an external force. In summer 2011 and 2012 a comprehensive set of ice model tests was performed in the large ice tank of the Hamburg Ship Model Basin (HSVA). The tests are related to the research and development project DYPIC — Dynamic Positioning in Ice. Within the project two phases of model tests have been performed. The first phase has been documented and presented in [1] while the second phase is presented in [2]. The model setups described and analyzed in this paper all relate to tests performed within the scope of DYPIC.Copyright © 2013 by ASME