Steady-State Turbulent Flow Simulations of the NASA High Lift Common Research Model in an Immersed Boundary Context

This paper examines several steady-state turbulent flow simulations of the NASA High Lift Common Research Model on Cartesian grids at increasing angles of attack. The Reynolds-Averaged Navier-Stokes equations are solved with the one-equation Spalart-Allmaras model, while the presence of a geometry is accounted for by an immersed boundary method based on a ghost cell direct forcing approach. A wall model is applied to address the inability of isotropic cells to accurately capture the near-wall flow physics at high Reynolds numbers. This work further validates the recent developments brought to the Cartesian methodology, which are based on a geometric regularization of the forcing point location around the immersed geometry. Additional developments are presented to improve the pre- and post-processing for this type of 3D applications. Comparisons are made with state-of-the-art solutions from the reference literature on body-fitted meshes, both structured and unstructured. A 2D multi-element airfoil is also studied to facilitate the analysis of the solutions obtained on the full aircraft in a high lift configuration. For higher angles of attack, more detailed investigations are proposed to better understand the physics closer to the stall phenomenon, especially near the wing tip.