PREDICTION OF ICE SHAPES AND THEIR EFFECT ON AIRFOIL DRAG

Calculation of ice shapes and the resulting drag increases are present ed for a NACA 0012 airfoil. The calculations were made using a combina tion of modified LEWICE and interactive boundary-layer codes for a wid e range of values of parameters such as airspeed and temperature, the droplet size and liquid water content of the cloud, and the angle of a ttack of the airfoil. Based on experimental data, an improved correlat ion of equivalent sand-grain roughness was developed. Calculated ice s hapes are in good agreement with experimental data for rime ice, but s ome differences are shown between predictions and experimental data fo r glaze ice. Calculated drag coefficients generally follow trends show n by the experimental data.