2D Simulation of the Icebreaking Pattern for Sea Ice Management

Sawamura, Junji (Osaka University) | Pedersen, Egil (UiT The Arctic University of Norway)

OnePetro 

ABSTRACT

This paper present a proposal of a numerical model for 2D simulation when an icebreaker is advancing into ice-covered waters. The ship-ice contacts, ice failure, and ice floe motion are modeled. The numerical simulation calculates the repeatable ice breaking and removal. Numerical modeling demonstrates ice management with a race track. The distribution of ice floes, open channels, and time history of ice force caused by the icebreaker’s ice management are obtained numerically. Example calculations demonstrate that the proposed numerical model can be useful to identify an efficient way of ship handling in ice-covered water.

INTRODUCTION

Ice management is necessary to reduce ice loads acting on tankers and drilling vessels operating in Arctic regions. An icebreaker works upstream of the vessels to create a continuous channel and to reduce floe size to manageable levels. Ice management requires a sufficiently large channel width and small floe size in drifting sea ice. Efficient ice management has to estimate the ice channel managed by the icebreaker, and support proper planning of vessel operations and deployed configuration.

Moran et al. (2006) reported ice management operations in the Arctic Coring Expedition (ACEX) conducted during August-September 2004 by the Integrated Ocean Drilling Project. In ACEX, two icebreakers worked upstream of the drill ship, which was able to stay at the location in heavy ice conditions about 250 km from the North Pole. He concluded that success was achieved through the efforts of the ice management, comprising individuals with extensive experience with Arctic icebreaking, ice prediction, and weather forecasting. Hamilton et al. (2011a, 2011b) developed a numerical simulator and quantified the ice management performance using real ice condition data collected in the Canadian Beaufort Sea. They studied effects of ice management strategies quantitatively, with examination of parameters of the icebreaker’s icebreaking pattern, speed of the ice, channel width, and ice floe size in the managed ice channel. Results show that the simulation provides variable insights into ice management fleet composition and fleet deployment. Full scale sea ice management trials in waters northeast of Greenland were conducted by the Oden Arctic Technology Research Cruise (OATRC) during the summers of 2012 and 2013 (Lubbad et al., 2013; Scibilia et al., 2014). Farid et al. (2014) investigated the sea ice breaking patterns of several short-term ice management activities during a research cruise in OATRC 2013, later proposing a preliminary analysis. They demonstrated that the maximum floe size resulting from the numerical simulations was roughly equivalent to that of an actual ship trial. Lu et al. (2015, 2016) examined ice floe fracture phenomena during the icebreaker’ s ice management. They proposed analytical and theoretical models of in-plane and out-plane ice failure for implementation into a numerical simulator of ship-ice interaction (e.g., Lubbad and Loset, 2011). The numerical simulation, as explained above, can determine an efficient ice management strategy. However, simulations have not led to efficient planning of ice management because of complexity of ice breaking and removal during ice managements.