  In this study, five ice shapes generated at NASA Glenn's Icing Research
Tunnel (IRT) are simulated at multiple angles of attack (Broeren et al., J. of
Aircraft, 2018). These geometries target different icing environments, both
early-time and longer-duration glaze and rime ice exposure events, including a
geometry that results from using a thermal ice-protection system. Using the
laser-scanned geometries, detailed representations of the three-dimensional ice
geometries are resolved on the grid and simulated using wall-modeled LES.
Integrated loads (lift, drag, and moment coefficients) and pressure
distributions are compared against experimental measurements in both clean and
iced conditions for several angles of attack in both pre-and post-stall
regions. The relevant comparisons to the experimental results show that
qualitative and acceptable quantitative agreement with the data is observed
across all geometries.
  Glaze ice formations exhibit larger and highly nonuniform ice features, such
as `horns', in contrast to rime ice formations characterized by smaller,
uniformly distributed roughness elements. In wall-modeled LES, it was observed
that larger roughness scales in the glaze ice that trigger transition can be
accurately resolved. Therefore, it is possible for WMLES to accurately capture
the aerodynamics of glaze ice shapes without the need for additional modeling.
In contrast, rime ice geometries required additional resolution to accurately
represent the aerodynamic loads. This study demonstrates the effectiveness of
the wall-modeled LES technique in simulating the complex aerodynamic effects of
iced airfoils, providing valuable insights for aircraft design in icing
environments and highlighting the importance of accurately representing ice
geometries and roughness scales in simulations.
