Improving the Prediction for the NASA High-Lift Trap Wing Model

Abstract

Results presented at the 1 st AIAA High Lift Prediction Workshop (HiLiftPW-1) using the flow solver Edge are summarized for the trap-wing model with two different flap settings. A comparative study of three different turbulence models is carried out, including the Explicit Algebraic Reynolds Stress Model (EARSM), the k-ω SST model and the Spalart-Allmaras (SA) model. The comparison shows that the overall best agreement with experimental data is obtained with the SA model, which has also predicted the maximum lift at about the correct experimental incidence. The two other models predict a larger flap trailing edge separation and, consequently, resulting in an under-prediction of lift. A grid refinement study has been undertaken, indicating that the unstructured grids are of a high quality. A good prediction of the wing tip flow is obtained with the full viscous operator. A thin-layer approximation changes the tip vortex structure with large deviations from experimental pressure distribution. The inclusion of the flap and slat support systems gives improved predictions of the integrated forces and moments, as well as of pressure distributions. There is a small under-prediction of lift at higher incidences due to an under-prediction of the rear main wing and flap suction peaks causing an earlier lift break down. Transition prediction has also been carried out based on stability analysis in several typical span-wise sections. The output is used to specify laminar regions in the 3D calculations, which has improved the results further in good agreement with experimental data for aerodynamic forces, moments and pressure distributions.