Aircraft Icing: Airfoil Surface

This project simulates the early stage of aircraft icing — the formation of a thin liquid water film on an airfoil surface as humid air laden with supercooled water droplets flows over it. The motivation is directly safety-driven: once this film forms, at low enough temperatures it can freeze on the wing, degrading lift and control. Predicting where and how thick the film forms is the first step in any anti-icing or de-icing design.

The physics is handled with the Eulerian Wall Film (EWF) model, layered on a Eulerian multiphase setup where air is the primary phase and liquid water droplets are the secondary phase, also defined as the constituent of the wall film. The EWF model is purpose-built to track the formation, thickness, and flow of a thin liquid layer along wall surfaces — and unlike VOF, it can impose and correct the film's initial wall conditions, giving cleaner control over the film-wall interaction. Note that EWF is a 3-D-only model and requires the Eulerian multiphase model to be active, which sets the structure of the whole case.

Setup: the air–droplet mixture approaches the airfoil at 30 m/s and 250 K, with a droplet volume fraction of 0.002. The airfoil wall is initialized with a film of specified height and zero velocity, and the case is run transient for 1 s at a tight time step of 1×10⁻⁴ s to resolve the film's growth and motion. Geometry is built in Design Modeler and meshed in ANSYS Meshing as an unstructured mesh (~978,532 elements).

What the results show: contours of density, pressure, air and water velocity, and air/water volume fractions, plus the key output — the film-thickness contour on the airfoil body — all at the final second. The thickness map reveals where impinging droplets accumulate into a film, which is exactly the region most at risk of freezing and the target for any icing-protection system.

You'll learn to: activate and configure the Eulerian Wall Film model on top of a Eulerian multiphase case, define droplet-laden inflow and a film-initialized wall, run a fine-time-step transient icing case, and read film accumulation from thickness and volume-fraction contours.