Young Researchers Workshop: Current trends in kinetic theory

Network modeling and analysis of sea ice permeability

Kyle Steffen

University of Utah

Sea ice is a multiscale composite material, covering about 7% of the Earth's ocean surface, and hosts a rich ecosystem of flora and fauna. Microorganisms living in its porous brine microstructure are exposed to extreme variations in salinity and temperature. Algae, such as the diatom Melosira arctica, secrete gelatinous exopolymeric substances (EPS), which are believed to protect them from their cold, salty environment. Recent experimental work has shown significant changes in the structure and properties of the brine inclusion microstructure with entrained Melosira EPS, including a decrease in fluid permeability. In my talk, I will discuss recent work on a model for the effective fluid permeability of young, EPS-laden sea ice, consisting of a random network of pipes, with cross-sectional areas chosen from a bimodal distribution. This distribution generalizes a classical lognormal distribution describing inclusions in young sea ice without EPS. I will also discuss rigorous anisotropic upper bounds for the effective fluid permeability of porous media, and its application in this context. Lastly, I will discuss future directions, such as tighter, isotropic upper bounds. This talk is based on joint work with Y. Epshteyn, J. Zhu, M. J. Bowler, J. W. Deming, and K. M. Golden.