Aerodynamic Effects of Anti-Icing Fluids on a Thin High-Performance Wing Section

Abstract

The Federal Aviation Administration has worked with Transport Canada and others to develop allowance times for aircraft operating in ice-pellet precipitation based upon wind-tunnel experiments with a thin high-performance wing. These allowance times are applicable to many different airplanes. Therefore, the aim of this work is to characterize the aerodynamic behavior of the wing section in order to better understand the adverse aerodynamic effects of anti-icing fluids and ice-pellet contamination. Aerodynamic performance tests, boundary-layer surveys, and flow visualization were conducted at a Reynolds number of approximately and a Mach number of 0.12. Roughness and leading-edge flow disturbances were employed to simulate the aerodynamic impact of the anti-icing fluids and contamination. In the linear portion of the lift curve, the primary aerodynamic effect is the thickening of the downstream boundary layer due to the accumulation of fluid and contamination. This causes a reduction in lift coefficient and an increase in pitching moment (nose up) due to an effective decambering of the wing. The stalling characteristics of the wing with fluid and contamination appear to be driven at least partially by the effects of a secondary wave of fluid that forms near the leading edge as the wing is rotated in the simulated takeoff profile. These results have provided a much more complete understanding of the adverse aerodynamic effects of anti-icing fluids and ice-pellet contamination on this wing.