Reynolds-averaged Navier-Stokes simulations of airfoils and wings with ice shapes

Numerical simulations using the Reynolds-averaged Navier-Stokes equations were conducted to investigate the effect of simulated ridge and leading-edge ice shapes on the aerodynamic performance of airfoils and wings. A range of Reynolds numbers and Mach numbers, as well as ice-shape sizes and ice-shape locations, were examined for the NACA 23012, the NLF 0414, and the NACA 3415 airfoils. The results were compared to experiments completed recently at NASA Langley and University of Illinois. Additional two thinner airfoil models and a tapered NACA 23012 wing were also studied to investigate ice-shape location effect for various geometries. Comparisons between simulation results and experimental force data showed favorable comparison up to the stall conditions, with improved fidelity for forward and smaller ice shapes. At and past stall condition strong separation occurs, and the aerodynamic forces were typically not predicted accurately for large upper-surface ice shapes. To alleviate this problem, a lift-break (pseudostall) condition was defined based on the lift-curve slope change. The lift break compared reasonably well with experimental stall conditions and indicated that the upper-surface critical ice-shape location tended to be near (and often in between) the location of minimum pressure and the location of the most adverse pressure gradient.