The density and structure of ice accretion predicted by a random‐walk model

A random-walk, ballistic-type model is used to simulate the ice accretion process due to impinging supercooled droplets. the model is applicable over a wide range of growth conditions including, in the limit, growth where the droplets freeze virtually as spheres (dry growth), and growth where the droplets spread into and across the ice surface losing their identity (wet growth). The structure and density of the ice are determined by the probabilities governing droplet motion and freezing during their random walk along the ice deposit. A relationship between the Macklin parameter, commonly used to relate atmospheric conditions to ice density, and the probabilities of droplet motion has been established. The ice density and accretion structure perdicted by the random-walk model agree qualitatively with experimental observations at the stagnation line on a fixed circular cylinder. The model also predicts finger-like ice structures for small values of droplet momentum, also in keeping with observations.