Computational Aerodynamic Analysis of Three-dimensional Ice Shapes on a NACA 23012 Airfoil

Abstract

The present study identifies a process for performing computational fluid dynamic calculations of the flow over full three-dimensional (3D) representations of complex ice shapes deposited on aircraft surfaces. Rime and glaze icing geometries formed on a NACA23012 airfoil model were obtained during testing in the NASA Glenn Research Center's Icing Research Tunnel (IRT). The ice shape geometries were scanned as a cloud of data points using a 3D laser scanner. The data point clouds were meshed using Geomagic software to create highly accurate models of the ice surface. The surface data was imported into Pointwise grid generation software to create the CFD surface and volume grids. It was determined that generating grids in Pointwise for complex 3D icing geometries was possible using various techniques that depended on the ice shape. Computations of the flow fields over these ice shapes were performed using the NASA National Combustion Code (NCC). Results for a rime ice shape for angle of attack conditions ranging from 0 to 10 degrees and for freestream Mach numbers of 0.10 and 0.18 are presented. For validation of the computational results, comparisons were made to test results from rapid-prototype models of the selected ice accretion shapes, obtained from a separate study in a subsonic wind tunnel at the University of Illinois at Urbana-Champaign. The computational and experimental results were compared for values of pressure coefficient and lift. Initial results show fairly good agreement for rime ice accretion simulations across the range of conditions examined. The glaze ice results are promising but require some further examination. NomenclatureAOA = Angle of Attack CFD = Computational Fluid Dynamics NCC = National Combustion Code C f = skin friction Re s = Reynolds number based on distance along the surface U ∞ = free stream velocity * = friction velocity

On the Fidelity of RANS-Based Turbulence Models in Modeling the Laminar Separation Bubble and Ice-Induced Separation Bubble at Low Reynolds Numbers on Unmanned Aerial Vehicle Airfoil

“…Numerical studies about the aerodynamics of iced airfoils were extensively reviewed by Stebbins [29] in 2019 and are not intended to be repeated in detail here. Most of the numerical studies were performed on wings with leading-edge horn Ice accretions [30][31][32][33][34][35][36][37][38][39][40] and spanwise ridge ice [41][42][43]. Baldwin-Lomax (BL) and the Spalart-Allmaras (SA) model for turbulence were the widely employed turbulence models in studies with horn ice.…”