Design of subscale airfoils with full-scale leading edges for ice accretion testing

A design procedure for subscale airfoils with full-scale leading edges that exhibit full-scale water droplet impingement characteristics in an incompressible, inviscid flow is presented. The design procedure uses validated airfoil design, flow analysis, and water droplet impingement simulation codes to accomplish the task. To identify and isolate important design variables in the design, numerous trade studies were performed. This paper presents the results of the trade studies and briefly discusses the role of important design variables in the subscale airfoil design. The effect of these design variables on circulation, velocity distribution, and impingement characteristics is discussed along with the accompanying implications and compromises in the design. A strategy to incorporate viscous effects into the design is also presented. This article also presents the design of a half-scale airfoil model with a 5% upper and 20% lower full-scale surface of the Learjet 305 airfoil leading edge and compares its aerodynamic as well as the droplet impingement characteristics with that of the Learjet 305 airfoil.