Evaluation of Flow Solver Accuracy using Five Simple Unsteady Validation Cases

The goal of this study was to evaluate the time accuracy of five different Navier-Stokes flow solvers using five simple two-dimensional validation cases. The five flow solvers included Cobalt, USM3D, FUN3D, Beggar and NASCART-GT. The five validation cases included the laminar flow over a circular cylinder, the laminar shock tube, the inviscid convecting vortex, the 18%-thick circular-arc airfoil and the NACA 0015 pitching airfoil. This study was conducted in an effort to better understand the capabilities of each flow solver for time-accurate calculations. The eventual goal of the project was to use one or more of these flow solvers to analyze the unsteady transonic flow over a fighter aircraft with stores in captive carriage. Evaluating the capabilities of each flow solver with simple validation cases rather than a complicated fighter aircraft was desirable.