Experimental Aerodynamic Simulation of a Scallop Ice Accretion on a Swept Wing

Abstract

Understanding the aerodynamic impact of swept-wing ice accretions is a crucial component of the design of modern aircraft. Computersimulation tools are commonly used to approximate ice shapes, so the necessary level of detail or fidelity of those simulated ice shapes must be understood relative to high-fidelity representations of the ice. Previous tests were performed in the NASA Icing Research Tunnel to acquire high-fidelity ice shapes. From this database, full-span artificial ice shapes were designed and manufactured for both an 8.9%-scale and 13.3%-scale semispan wing model of the CRM65 which has been established as the full-scale baseline for this sweptwing project. These models were tested in the Walter H. Beech wind tunnel at Wichita State University and at the ONERA F1 facility, respectively. The data collected in the Wichita St. University wind tunnel provided a low-Reynolds number baseline study while the pressurized F1 facility produced data over a wide range of Reynolds and Mach numbers with the highest Reynolds number studied being approximately Re = 11.9×10 6 . Past work focused on only three different fidelity variations for ice shapes based on multiple icing conditions. This work presents a more detailed investigation into several fidelity representations of a single highly three-dimensional scallop ice accretion. Sensitivity to roughness size and application technique on a low-fidelity smooth ice shape is described. The data indicate that the aerodynamic performance is not especially sensitive to the grit variations. An ice accretion code was also used to generate ice shapes for aerodynamic testing and comparisons. These ice shapes have a general appearance like the low-fidelity smooth ice shapes, but in this case, the computer-generated ice shape is significantly smaller. As such, the impact of that ice shape on the aerodynamic performance of the wing is reduced compared to the smooth ice shape based on the icing experiment for those same conditions. Spanwise discontinuities were also introduced to a lowfidelity ice shape in an attempt to quantify the impact of those variation in the high-fidelity ice shape. While the lift data indicate good agreement between the high-fidelity ice shapes and the lowfidelity ice shapes with spanwise discontinuities, a closer investigation of the data suggests potential, significant differences in the flowfield. These results were similar at both facilities over the wide range of test conditions utilized.10/19/2016 developing these artificial ice shapes [8]. During that project, the current methods for capturing three-dimensional geometries were not available, but more recently a method for creating high-fidelity artificial ice shapes has been validated using 3-D laser scanning and rapid-prototype manufacturing [9]. That methodology was utilized for this project. With these capabilities applied to the swept-wing ice accretion database, numerous artificial ice shapes are available for wind tunnel testing for aerodynamic performance effects. Both lowand high-Reynolds...

Additional Comparison of Iced Aerodynamic Measurements on a Swept Wing from Two Wind Tunnels

“…A detailed description of how "3D Smooth" ice shapes were generated can be found in Camello, et al [23,25] Details of "Max Scallop" ice shapes presented in this paper can be found in Woodard, et al [14], and details of the "WB33" ice shapes can be found in Broeren, et al [15] a) Clean wing.…”

“…The artificial ice-shape geometries were based on those obtained during ice accretion tests at NASA Icing Research Tunnel with CRM65 wing sections [8]. The results from the iced aerodynamic tests in this research program have been published in various reports [9][10][11][12][13][14][15][16].…”