Under the big-ice: fluid-ice structure interaction of the Drygalski ice tongue

• Main Authors: Edwards, C, Forrest, AL, Leong, ZQ, Yun, S, Lee, WS
• Format: Conference Object
• Language: English
• Published: International Association of Hydro-Environment Engineering and Research 2016
• Subjects: Engineering; Maritime Engineering; Marine Engineering; Drygalski; Drygalski Ice Tongue; McMurdo Sound; Antarc*; Antarctica
• Online Access: http://ecite.utas.edu.au/110177

The Drygalski Ice Tongue (DIT) is the largest floating glacier in Antarctica, extendingapproximately 120km into McMurdo Sound, and exhibits a significant influence upon theprevailing northward current, as the ice draft of the majority of the DIT is greater than the depthof the observed well-mixed surface layer. This influence is difficult to characterize usingconventional methods such as in-situ LADCP measurements, vertically collected profiles or longterm moorings as these are generally relatively spatially sparse datasets. In order to better relatemeasurements across the entire region of influence of the DIT region, a set of Computational FluidDynamics (CFD) simulations were conducted using a generalized topography of a mid-spantransect of the DIT. CTD and LADCP measurements made in close (<100 m) proximity of theDIT were used as boundary conditions for the model. These measurements revealed a layeredstructure in the water column typical of the region, with salinities varying from 34.3 g/kg at thesurface to 34.81 g/kg at approximately 1200 m depth. The degree of mixing and the associatedsharpening of the pycnocline varied greatly over the observation period of 4 days. The CFD work,using Large Eddy Simulation (LES) for a homogeneous two-layer water column independentlyproduced an estimated region of influence of the ice structure approximately 3km and 7kmupstream and downstream of the DIT respectively for a given flow regime. Numerical modelingof environmental flows around ice structures advances the knowledge of the fluid dynamics of thesystem in not only the region surrounding the DIT but also provides a clearer insight into fluid-icestructure interactions and heat flux in the system. This may lead to a better understanding of thelong-term fate of floating glaciers.