Recent research in sub-scale ice accretion aerodynamic simulation and the current state of understanding in this area are reviewed. The flowfields and defining aerodynamic characteristics of the main types of ice accretion are discussed: ice roughness, streamwise ice, horn ice, and spanwise-ridge ice. Reynolds number effects are found to be small in many cases, but additional data are needed for certain types of accretion from Re = 2.0 x 10⁶ – 5.0 x 10⁶. Uncertainties in representing ice accretion geometry are substantial and in many cases may cause differences in aerodynamic performance on the order of the differences observed between a sub-scale simulation and the corresponding accretion. It is found that directly scaling roughness height on ice roughness, streamwise ice, and short-ridge ice simulations tends to produce conservative estimates of aerodynamic performance. Surface roughness is not usually necessary to accurately represent horn-ice simulations but improves the fidelity of tall-ridge simulations.