ABSTRACT
In the study presented in this paper, the problem of quantifying the performance of icebreaker operations within ice management (IM) has been targeted, using the capabilities of high-fidelity simulations by a discrete element simulation model. An accurate geometric and dynamic model of the icebreaker IB Oden, as well as the characterization of a realistic multi-domain ice environment, has been numerically modeled within the simulator. The simulator includes features to easily vary parameters such as ice thickness, ice concentration, floe size distribution, and ice drift velocity and direction. The protected structure is modeled as a cylindrical structure, acting as a measurement probe of the ice loads, ice actions, ice-ice and ice-hull friction resulting from various simulated operations and scenarios. In overall, this give us the tools we need to numerically model, with high fidelity, complex icebreaker operations on realistic ice conditions in order to quantify the performance of IM strategies under various scenarios. This can give us better insight into which IM strategies that are effective, thereby enabling better planning and online guidance of icebreaker operations.
In recent years the interest for the Arctic has been growing due to the presence of rich natural resources and its strategic location, including the Northern Sea Routes. The design of Arctic offshore structures and marine operations are complicated by the presence of sea ice compared to open water experiences. To ensure a safe operation and design, ice management (IM) is often employed as a risk-reducing measure. This is defined as the sum of all activities from any kind of ice features (Eik, 2008), e.g., protecting a downstream offshore structure from severe ice features by one or more icebreakers. An illustration of the IM concept can be seen in Fig. 1.
The IM operation is a complex and integrated system that involves detection, tracking, forecasting, decision making, and eventually handling the detected threatening ice features. When planning such an operation, practical questions such as how many icebreakers that are needed and how to deploy the available icebreaker fleet to most effectively defend an offshore structure, are often addressed based on heuristic data and rather simplified models of icebreaker efficacy. An often used method is the kinematic model by Hamilton et al. (2011a,b) and Hamilton (2011). This model were successfully used in a systematic approach to ice management operations in a full-scale, real-life environment during the Oden Arctic Technology Research Cruise 2015 (OATRC2015) program (Lubbad et al., 2018a; Holub et al., 2018).
