Melting Gives Ice Block a Push
Drifting icebergs are pushed mainly by wind but also by ocean currents and surface waves. Now Michael Berhanu of Paris Cité University, Arshad Kudrolli of Clark University in Massachusetts, and their colleagues have demonstrated another potential source of iceberg motion: the melting process [1]. The team produced ice blocks with bottom surfaces that were inclined rather than horizontal and floated them in water. The researchers found that for water temperatures from 10 to 30 °C, a roughly 20-cm-long ice block reaches speeds of about 3 mm/s. As cold water sinks from the region close to the ice, fresh fluid cannot easily replace it because of the presence of the solid. As a result, the sinking fluid remains close to the block, sliding down the inclined surface and creating a sort of underwater jet that propels the block.
The team’s analytical model accounts for factors such as temperature and block size and correctly predicts the ice block’s speed for a range of parameters. The researchers estimate that when icebergs drift into warmer waters, such as near Newfoundland, Canada, meltwater-driven propulsion could have a significant impact on iceberg motion, contributing up to about 10% of the effect of wind.
–David Ehrenstein
David Ehrenstein is a Senior Editor for Physics Magazine.
References
- M. Berhanu et al., “Self-propulsion of floating ice blocks caused by melting in water,” Phys. Rev. Fluids 11, 033802 (2026).