Numerical modelling of tsunamis generated by iceberg calving validated with large-scale laboratory experiments

When calving icebergs interact with water, waves of tens of meters in height, so-called iceberg-tsunamis (IBTs), may be generated. Recent examples include an IBT which reached an amplitude of 45 to 50 m in Eqip Sermia, Greenland, in 2014. A novel numerical methodology and unique large-scale laboratory experiments are presented to investigate the generation and propagation of such IBTs. In the laboratory the IBTs were generated with rigid blocks in a 50 m x 50 m basin. For the numerical model a multiphase flow solver is extended by coupling it with a motion solver to handle dynamic immersed boundaries such as the surfaces of floating icebergs. An analytical solution of the radiated waves by a heaving sphere in still water, a vertically falling and an overturning block experiment are used to validate the numerical model. The model simulates the laboratory IBTs with a maximum relative error of 15.5% in the first (leading) wave amplitude and 13.8% in the wave height decay exponent if the splash is ignored. The validated model is then used successfully to replicate the 2014 Eqip Sermia IBT. This new numerical model is expected to be useful for IBT hazard assessment and many further floating body phenomena.