A Phase-Field Model\nfor Wet Snow Metamorphism

The microstructure\nof snow determines its fundamental properties\nsuch as mechanical strength, reflectivity, or thermo-hydraulic properties.\nSnow undergoes continuous microstructural changes due to local gradients\nin temperature, humidity, or curvature, in a process known as snow\nmetamorphism. In this work, we focus on wet snow metamorphism, which\noccurs when the temperature is close to the melting point and involves\nphase transitions among liquid water, water vapor, and solid ice.\nWe propose a pore-scale phase-field model that simultaneously captures\nthe three relevant phase change phenomena: sublimation (deposition),\nevaporation (condensation), and melting (solidification). The phase-field\nformulation allows one to track the temperature evolution among the\nthree phases and the water vapor concentration in the air. Our three-phase\nmodel recovers the corresponding two-phase transition model when one\nphase is not present in the system. 2D simulations of the model unveil\nthe impact of humidity and temperature on the dynamics of wet snow\nmetamorphism at the pore scale. We also explore the role of liquid\nmelt content in controlling the dynamics of snow metamorphism in contrast\nto the dry regime before percolation onsets. The model can be readily\nextended to incorporate two-phase flow and may be the basis for investigating\nother problems involving water phase transitions in a vapor–solid–liquid\nsystem, such as airplane icing or thermal spray coating.