Fluid-structure modeling of iceberg capsize
Résumé
Ice sheet evolution models require consideration of ocean-glacier processes such as iceberg calving. The capsize of large icebergs from marine-terminating glaciers as a result of calving generates teleseismic waves that contain information about the physical processes involved. Deriving the calved iceberg volume from the seismic signal requires the coupling of seismic inversion with numerical simulation of the capsize, which currently lacks high-fidelity hydrodynamic effects. Therefore, a Computational Fluid Dynamics model combining a Reynolds Averaged Navier-Stokes Equations solver with a volume penalization method and a spring-damper contact force formulation is used to simulate the capsize of an iceberg colliding with a glacier front. The modeled capsizes are in good agreement with laboratory-scale experimental results from the literature, for many configurations (capsize in the open ocean or in contact with a floating or grounded glacier terminus, for bottom-out or top-out configurations and several iceberg aspect ratios). In grounded glacier configurations, we show that the lateral flow confinement effects are significant. The initial iceberg tilt angle and the iceberg/glacier friction coefficient have little influence. Turbulence mainly affects the post-capsize iceberg drift velocity. In addition, a field-scale 200 m high iceberg capsize simulation shows near-field water velocities in excess of 10 m/s.
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