Convection from laser-scanned real ice roughness on a simulated NACA 0012 airfoil.

Aircraft surfaces develop ice accretions under certain in-flight conditions. Ice accretions on aircraft surfaces increase skin friction drag, decrease lift, and increase the aircraft weight. Computational models of ice accretion on airfoils can be performed with the LEWICE code developed at the NASA Glenn Research Center. Previous research to improve the convection models in LEWICE used multiple surface representations of ice roughness in both accelerated flows and flows with negligible acceleration. However, the earlier work used simulated surface roughness elements such as cones and hemispheres to enhance convective heat transfer. The current research examines convective heat transfer along test plates with surface panels replicating laser-scanned real ice roughness along the leading 17.1% (3.6 in.) of a 21 in. NACA 0012 airfoil. A new leading edge trip is also used to force turbulent flow over the surfaces for comparison with data from naturally transitioning flow cases.