Numerical Simulation of Ice Formation on a Helicopter Fuselage 2007-01-3308

Over the past few years, we have developed a unique approach to simulate aircraft icing numerically; we call this method morphogenetic modelling. Previously, we developed a successful two-dimensional version of the model; the objective of our present research is to show that the morphogenetic modelling approach can be extended to three-dimensional in-flight icing. In this paper, we focus on the simulation of three-dimensional, discrete rime structures forming on the fuselage of a helicopter. The numerical model consists of three components: an airflow solver, a drop trajectory solver, and a morphogenetic ice growth model. The velocity field of the flow is computed using the Euler equations, while the drop trajectories are computed using a Lagrangian approach. Computation of drop impact locations determines the local collision efficiency distribution. The morphogenetic model deals with the processes occurring on the impinging surface. Depending on atmospheric conditions, impinging drops may freeze instantly or they may move along the surface before freezing. By building the ice accretion one particle at a time, the morphogenetic model simulates the time evolution of the accretion shape in a natural way that mimics real world behaviour.