On the Use of Artificial Ice Shapes for Large-Eddy Simulations in Aircraft Icing

Large-eddy simulations (LES) are used to investigate the aerodynamic performance of a semispan swept-wing model based on the NASA Common Research Model. Two ice shapes are considered: 1) a real ice shape from laser-scanning accreted ice in the NASA Icing Research Tunnel and 2) an artificial ice shape derived from the maximum combined cross-section of the 3D ice accretion. Simulations are performed in free air at Reynolds numbers, [Formula: see text], of [Formula: see text], [Formula: see text], and [Formula: see text], with a Mach number of 0.18. Integrated loads, pressure distributions, and wall-shear stress visualizations are compared to experiments over various angles of attack. Grid resolution studies show good agreement for the real ice geometry, with lift coefficient differences within three counts ([Formula: see text]). The artificial ice geometry, however, shows greater sensitivity to grid resolution. Despite good agreement in lift for the artificial ice shape, discrepancies in drag and moments are observed. Pressure profiles suggest error cancellation, explaining the lift agreement. The smooth surfaces in the artificial ice shape introduce laminar boundary layers, laminar separation, and turbulent transition, unlike real ice, where roughness triggers immediate transition. These findings highlight the importance of incorporating appropriate roughness scales into artificial or predicted ice shapes for practical LES in iced aircraft configurations.