19th AIAA Computational Fluid Dynamics Conference Comparison of Overset Grid and Grid Deformation Techniques Applied to 2-Dimensional NACA Airfoils

This paper documents a comparison of overset grid and grid deformation schemes ap-plied to flapped and non-flapped NACA airfoil configurations in order to determine the relative accuracy and computational efficiency of each method. This study is part of a larger effort to use computational fluid dynamics to perform moving control surface cal-culations. Three different cases, using both overset and deformed grids, are considered, including: a) lift and moment comparison of a quasi-steady, non-flapped 0012 airfoil, b) lift and moment comparison of a dynamically pitching non-flapped 0012 airfoil, and c) lift comparison of a dynamic pitching and oscillating flapped 0012 airfoil. These results are compared to experimental data from various sources. Two flow solvers of common lineage were used for the computations: Cobalt for overset and rigid mesh motion and AVUS for the deformable mesh motion. All of the methods produced nominally similar results. As expected, the rigid mesh technique required the least amount of computational resources, while the deformable mesh technique required the greatest amount of computational re-sources due to its serial implementation. However, in the end, it is difficult to recommend one method over another as the application of each method may be dependent on the project being solved. Nomenclature c Airfoil chord length Cl Lift coefficient, Cl=l/(q c) Cm Pitching moment coefficient, Cm=Mz/(q c2) Cy Normal force coefficient, Cy = fy/(q c) fy Normal forc