We performed direct numerical simulations to investigate the interaction of a vertical ice interface with seawater, and particularly the small-scale convection generated when a wall of Antarctic ice melts in the salty and warmer seawater. The three coupled interface equations are used, along with the Boussinesq and non-hydrostatic governing equations of motion and equation of state for seawater, to solve for interface temperature, salinity and melt rate. Fluxes of both heat and salt to the interface play significant roles in rate of ice melting. The main focus is on the dissolving of ice (at ambient water temperatures between −1° C and 6° C and salinity around 35 ‰) as characterizes many sites around Antarctica. Under these conditions the diffusion of salt to the ice-waterinterface depresses the freezing point and further enhances heat diffusion to the ice.
Research Article| January 01, 1994 Influence of cooling on lava-flow dynamics: Comment and Reply John R. Lister; John R. Lister 1Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, Silver Street, Cambridge, CB3 9EW, United Kingdom Search for other works by this author on: GSW Google Scholar Ross C. Kerr; Ross C. Kerr 2Research School of Earth Sciences, Australian National University, Canberra, A. C. T. 0200, Australia Search for other works by this author on: GSW Google Scholar Mark V. Stasiuk; Mark V. Stasiuk 3Department of Geology, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom Search for other works by this author on: GSW Google Scholar Claude Jaupart; Claude Jaupart 3Department of Geology, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom Search for other works by this author on: GSW Google Scholar R. Stephen; R. Stephen 3Department of Geology, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom Search for other works by this author on: GSW Google Scholar J. Sparks J. Sparks 3Department of Geology, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom Search for other works by this author on: GSW Google Scholar Geology (1994) 22 (1): 93–94. https://doi.org/10.1130/0091-7613(1994)022<0093:IOCOLF>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation John R. Lister, Ross C. Kerr, Mark V. Stasiuk, Claude Jaupart, R. Stephen, J. Sparks; Influence of cooling on lava-flow dynamics: Comment and Reply. Geology 1994;; 22 (1): 93–94. doi: https://doi.org/10.1130/0091-7613(1994)022<0093:IOCOLF>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract No abstract available This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
The emplacement of the 1988–1990 andesite lava of Lonquimay Volcano, Chile is examined using theoretical expressions for the relevant dynamical flow regimes. The surface crust regime, where the flow is controlled by the growth of a surface crust rather than by the rheology of the fluid interior, is found to predict accurately the entire propagation of the Lonquimay lava flow. This discovery offers the exciting prospect of being able to predict the propagation of future blocky lavas, simply from early observations of both the volume erupted and the flow length as functions of time, without the need to know anything about the rheology of the interior lava.
The effects of the slope of an ice–seawater interface on the mechanisms and rate of ablation of the ice by natural convection are examined using turbulence-resolving simulations. Solutions are obtained for ice slopes $\unicode[STIX]{x1D703}=2^{\circ }{-}90^{\circ }$ , at a fixed ambient salinity and temperature, chosen to represent common Antarctic ocean conditions. For laminar boundary layers the ablation rate decreases with height, whereas in the turbulent regime the ablation rate is found to be height independent. The simulated laminar ablation rates scale with $(\sin \unicode[STIX]{x1D703})^{1/4}$ , whereas in the turbulent regime it follows a $(\sin \unicode[STIX]{x1D703})^{2/3}$ scaling, both consistent with the theoretical predictions developed here. The reduction in the ablation rate with shallower slopes arises as a result of the development of stable density stratification beneath the ice face, which reduces turbulent buoyancy fluxes to the ice. The turbulent kinetic energy budget of the flow shows that, for very steep slopes, both buoyancy and shear production are drivers of turbulence, whereas for shallower slopes shear production becomes the dominant mechanism for sustaining turbulence in the convective boundary layer.
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