Numerical simulations of ice forces on the Kulluk: the role of ice confinement, ice pressure and ice management

• Published in: All Days
• Main Authors: Sayed, Mohamed, Kubat, Ivana, Wright, Brian
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Offshore Technology Conference 2012
• Subjects: conservation of mass; field measurement; governing equations; heterogeneous ensembles; moored structures; plastic yield criterion; pressure conditions; quantitative comparison; computer simulation; ice problems; meteorological problems; mooring; numerical models; ice; Arctic; Beaufort Sea
• Online Access: https://doi.org/10.4043/23823-MS; https://nrc-publications.canada.ca/eng/view/object/?id=2ad04b7d-e3a8-4d27-8248-d8222fe87868; https://nrc-publications.canada.ca/fra/voir/objet/?id=2ad04b7d-e3a8-4d27-8248-d8222fe87868

The interaction of managed ice covers with a wide structure is examined. Numerical simulations are used to simulate the modes of ice cover deformation and forces on the structure. The objective of the present work is to validate the performance of the numerical model using historical data recorded during operations of the Kulluk in the Beaufort Sea during the 1980s and early 1990s. This paper is the last part of an investigation aimed at developing an approach for modeling managed ice interaction with wide moored structures. Previous papers examined the role of the mooring system (Sayed and Barker, 2011) and the effects of ice cover confinement and managed floes sizes (Sayed et al., 2012). The focus of the present paper is on providing quantitative comparison between predicted ice force statistics and observations. The numerical model is based on solving equations describing the conservation of mass and linear momentum together with a plastic yield criterion that describes ice properties. The managed ice cover consists of a heterogeneous ensemble of relatively small floes. The floes are assigned varied thickness values in order to reflect field conditions. The simulations address a class of interaction scenarios corresponding to confined managed ice. As the ice cover is driven within confined boundaries, pressure conditions arise. These conditions are of interest to designers since forces are considerably higher than those corresponding to unconfined ice covers. The solution of the governing equations simulate the evolution of the distributions of ice thickness, concentration (or coverage) and stresses. The resulting ice forces, including peak values, averages and rise-time of forces, are compared to field measurements. The influence of ice thickness and velocity on expected ice forces is also examined. Peer reviewed: Yes NRC publication: Yes