NUMERICAL SIMULATION OF COMPLEX ICE SHAPES ON SWEPT WINGS

摘要

In this paper, we present a three-dimensional, morphogenetic model that simulates discrete rime ice accretion structures forming on a swept wing. Rime is an ice deposit caused by the impingement and freezing, in situ, of supercooled cloud droplets at ice accretion temperatures below 0℃. Depending on conditions, the droplets may freeze as spheres or deform on the surface, but for rime to form, surface liquid flow is limited or non-existent. In our model, roughness elements that develop initially on the wing surface evolve into rime feathers and other complex, three-dimensional structures. On swept wings, these resemble the so-called "lobster tails " or "scallops " that are observed in wind tunnels and inflight. We show the results of numerical model sensitivity tests, performed as a function of two model parameters: sweep angle and freezing range parameter. This exploratory research indicates that the model can predict realistic-looking, three-dimensional ice structures on swept wings. To the best of our knowledge, this capability does not exist in any current in-flight ice accretion models.