Development of a Navier-Stokes solver to analyze compressible flow about airfoils and wings altered by leading edge ice accretions

It is well known that the accumulation of ice on aircraft can produce disastrous results. Thus arises the need for accurate prediction of the performance of iced airfoils and wings. In the present study a Navier-Stokes solver capable of simulating three dimensional turbulent flow in an arbitrary coordinate system is developed. The code, which makes use of finite difference approximations and MacCormack's explicit method to solve the governing equations, is then used to analyze changes in the flow field brought about by the presence of leading edge ice. Through extensive comparison with experimental and previously obtained numerical data the solver is proven to be reliable and capable of producing realistic results over a wide range of parameters.; The principal results obtained from this research indicate that the presence of a highly irregular ice accretion on an airfoil/wing significantly changes the overall character of the flow. This is mainly due to the appearance of an icing horn which promotes reverse flow at the leading edge causing premature stall and excessive drag. Higher speeds seem to somewhat reduce these detrimental effects whereas lower Reynolds numbers greatly exacerbate them indicating that the effects of icing are most dangerous during take-off and landing. Additionally, investigation of complete wings has shown that the combination of spanwise velocities and recirculation bubbles make for a complex flow field which differs appreciably from its two dimensional analogue.