A computational investigation was conducted to determine the effect of simu
lated upper-surface spanwise ice shapes on airfoil aerodynamics. These shap
es are representative of supercooled large droplet shapes on aircraft with
active de-icing boots. The numerical investigation employed steady-state si
mulations with a high-resolution full Navier-Stokes solver using a solution
-adaptive unstructured grid for both non-iced and iced configurations. The
study investigated a modified NACA 23012 (with and without flap deflection)
and airfoils of the NASA Modern Airfoil program. A range of protuberance l
ocation, size, and shape were examined, and comparisons were made to availa
ble experimental data. In general, the performance of the computational met
hodology was particularly good for pressure and hinge-moment distributions
(including the nonlinear break points), whereas lift was predicted reasonab
ly well up to (but not past) fully separated flow conditions. The airfoil s
hape sensitivity studies indicated that the NACA 23012m exhibited the most
detrimental performance with respect to lift loss, which tended to be great
est around x/c of about 0.1 that also corresponds to the location of minimu
m C-p. The more evenly loaded NLF 0414 airfoil tended to have less separati
on for equivalent clean-airfoil lift conditions and did not exhibit a uniqu
e critical ice-shape location. The forward-loaded airfoils of the business
jet main wing model and the commercial transport horizontal tailplane model
exhibited critical ice-shape locations close to the leading edge (x/c = 0.
02), which was close to the minimum C-p location.