Summary Data from the Sixth AIAA Computational Fluid Dynamics Drag Prediction Workshop: Code Verification

Abstract

Results from the Sixth AIAA Computational Fluid Dynamics Drag Prediction Workshop: Case 1 Code Verification are presented. This test case is for the turbulent flow over a two-dimensional NACA 0012 airfoil using Reynolds-averaged Navier–Stokes turbulence models. A numerical benchmark solution is available for the standard Spalart–Allmaras turbulence model that can be used for code verification purposes. There are 31 data submissions from 16 teams: 23 with the SA model (various versions), 4 with -omega SST (two variants), and one each with , -epsilon, an explicit algebraic Reynolds stress model, and the lattice Boltzmann method with very large eddy simulation. Various grid types were employed including structured, unstructured, Cartesian, and adapted grids. The benchmark numerical solution was deemed to be the correct solution for the 21 submissions with the standard Spalart–Allmaras model, the Spalart–Allmaras without the term variant, and the negative Spalart–Allmaras mode variant. Although many of these 21 submissions demonstrate first-order convergence on the finer meshes, others either showed nonconvergent solutions in terms of the aerodynamic forces and moments or converged to the wrong answer. Results for this case highlight the continuing need for rigorous code verification to be conducted as a prerequisite for design, model validation, and analysis studies.