Aerodynamic simulations of airfoils with upper-surface ice-shapes

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.