Numerical Simulation of Tsunamis Generated by Iceberg Calving

When icebergs calve into water, large tsunamis can be generated. This hazard has been highlighted in a number of recent studies and may threaten the fishing and shipping industries and coastal communities. For example, a harbour in Greenland was damaged by a tsunami generated by a capsizing iceberg in 1995 and a 50 m high wave has been recorded following an iceberg calving event at the Eqip Sermia glacier in Greenland in 2014.

This work aims to numerically simulate the generation and propagation of these iceberg-tsunamis. This involves the challenging problem of handling large displacements of icebergs in the computational domain which is resolved by using the Immersed Boundary Method (IBM). In the IBM the surface of the iceberg is represented by cells in a fixed Euler mesh such that the mesh remains fixed during the movement of the body. The original multiphase flow solver relying on the IBM in the open source code Foam-extend has been modified to handle moving immersed boundaries. A tailored motion solver is coupled with a flow solver to determine the iceberg motion and the resulting iceberg-tsunamis. This new numerical model is in principle capable of simulating the entire range of iceberg calving mechanisms as well as related phenomena such as floating structure dynamics.

The method is validated with a theoretical floating heaving sphere case and large-scale iceberg-tsunami tests from a HYDRALAB+ test campaign involving a falling and overturning iceberg. The results show that the numerical iceberg motion and tsunamis generally agree with the laboratory observations. Further, the presented model can capture the laboratory wave amplitude and height decays well. In future work, more effort is required to also better predict the wave troughs and to simulate additional iceberg calving scenarios, as well as to consider turbulence.