This research provides new insight into how ice melts and forms when interacting with moving water, salt, and temperature differences, combining advanced computer simulations with carefully designed experiments.
A major methodological advance is a new simulation framework that accurately tracks melting ice as it moves, rotates, and changes shape in flowing water. This makes it possible to reliably predict how fast ice melts and how its shape evolves, even as it shrinks. Using this approach, the study shows that ice bodies can strongly influence each other: ice pieces aligned side by side tend to melt independently, while those stacked vertically interact through buoyancy-driven flows, which can either speed up or slow down melting depending on their spacing. These effects arise from a balance between cold water layering, which suppresses heat transfer, and convective mixing, which enhances it.
Ice shape also plays a crucial role. Changing the geometry can lead to unexpected changes in melt rates due to competing melting mechanisms and flow separation. In flowing water, elongated ice shapes aligned with the current can melt much more slowly than round ones, underlining the importance of geometry when estimating ice loss. Salinity adds further complexity: salt alters flow patterns around melting ice, stabilizes its motion, and creates distinctive surface features, yet simple scaling laws for melt rates remain surprisingly robust across many conditions. At very large scales, the research reveals a fundamental transition from slow, surface-controlled melting to much faster melting dominated by turbulent transport.
The work also sheds light on how ice forms. When water freezes, gas bubbles are almost always trapped inside, giving ice its white appearance. The study uncovers the physics behind this process, explaining why bubbles become elongated and asymmetric rather than spherical. A simple mathematical model captures their shapes and even explains the formation of long, worm-like pores observed in glaciers. These findings allow freezing conditions to be inferred from bubble shapes and support the design of porous materials made by freezing.
Overall, the results deepen our understanding of melting and freezing processes relevant to climate science, oceanography, energy systems, and materials engineering.
