Analysis of the Common Research Model Using Structured and Unstructured Meshes

Abstract

Two general-purpose Reynolds-averaged Navier–Stokes flow solvers, OVERFLOW and BCFD, are used to analyze the NASA Common Research Model in a wing–body configuration. The codes are run on structured and unstructured common-grid families built specifically for the Fifth AIAA CFD Drag Prediction Workshop, allowing for a meaningful comparison of data. The results from a grid-convergence study are evaluated for each solver and grid type with focus on isolating individual effects of turbulence model and differencing scheme on computed forces, moments, and wing pressures. A medium mesh consisting of 5.1 million cells is used for a buffet-onset study to better understand variations in high-speed wing-separation prediction driven by the strengthening shock and by corner-flow physics at the wing–body juncture. Numerical simulation of side-of-body separation continues to be a challenge for Reynolds-averaged Navier–Stokes methods, in which solutions are sensitive to grid density and turbulence model, among other variables. However, a newly developed quadratic constitutive relation is employed with favorable results. Two additional studies are conducted to 1) investigate how well common-grid solutions compare with those on a grid built using best practices for a given flow solver, and 2) quantify the effects of transition and wing twist to provide insight on how the comparisons of computational fluid dynamics results with experimental data may be influenced.