Detached Eddy Simulation on a Swept Hybrid Model in the IRT

In recent years, there has been a growing desire to incorporate computational methods into aircraft icing certification practices. To improve understanding of ice shapes, a new experimental program in the NASA Icing Research Tunnel (IRT) will investigate swept hybrid models which are very large relative to the test section and are intended to operate at high lift coefficients. The present computations were conducted to help plan the experiments and to ascertain any effects of flow separation and unsteady forces. As they can be useful in robustly and accurately predicting large separation regions and capturing flow unsteadiness, a Detached Eddy Simulation (DES) approach has been adopted for simulating the flow over these large high-lift wing sections. The DES methodology was first validated using experimental data from an unswept NACA 0012 airfoil with leading-edge ice accretion, showing reasonable performance. For the hybrid geometries in the IRT, the present predictions yielded a large separation bubble that develops at the junction between the model and the IRT ceiling. However, the separation region does not negatively impact the flow around the wing section centerline, where the flow is attached and consistent with desired conditions (with reasonable load dynamics). Addition of a leading-edge ice shape yielded similar behavior but with a slight change of lift coefficient of the model coupled with increased drag and moment loads.