Abstract:  Mesh convergence of RANS solutions for a multi-element airfoil and the NASA Juncture Flow Model computed with a variety of flow solver software packages using output-based adapted meshes are compared with solution convergence computed using expert crafted meshes adhering to "best practices”. The adapted meshes are generated using an optimization process implemented with the MIT Solution Adaptive Numerical Simulator (SANS) software. The adaptation process seeks to find a mesh that minimizes the error estimate of a given output functional subject to a maximum number of degrees of freedom. The multi-element airfoil expert crafted meshes are the result of a systematic study of the influence of a range of meshing parameters on solution accuracy, and the expert crafted meshes are generated by based on decades of experience with generation “best practice” meshes. Using the adapted meshes generally leads to more than one order of magnitude reduction in lift and drag error relative to the expert crafted meshes of a comparable node count for all of the CFD solvers. Alternatively, the node counts of the adapted meshes are more than an order of magnitude smaller than the manually generated meshes for a given lift and drag error level.