Ablation of sloping ice faces into polar seawater

Mainak Mondal*, Bishakhdatta Gayen, Ross W. Griffiths, Ross C. Kerr

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    27 Citations (Scopus)

    Abstract

    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 θ = 2°-90°, 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 (sinθ)1/4, whereas in the turbulent regime it follows a (sin θ)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.

    Original languageEnglish
    Pages (from-to)545-571
    Number of pages27
    JournalJournal of Fluid Mechanics
    Volume863
    DOIs
    Publication statusPublished - 25 Mar 2019

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