FaSTAR Results for the First AIAA Stability and Control Prediction Workshop

The test cases of the first AIAA Stability and Control Prediction Workshop were computed with an unstructured-grid CFD solver, FaSTAR. The lateral-directional static stability was analyzed for NASA Common Research Model (CRM) with a vertical tail. We show results of grid convergence, Mach number effect, and wind tunnel sting increments. The side force and yawing moment converged to the different values, depending on the grid and turbulence model. We found that this is caused by the separation at the juncture of horizontal tail. Though this separation bubble is not so well-known as the one appearing at the main wing juncture, the same kind of separation bubble appears near the tail juncture when the sideslip angle is not zero. The separation bubble becomes small or disappears when the quadratic constitutive relation (QCR) model is employed. As for the Mach number effect, the side force and yawing moment differ largely, depending on the grid and turbulence model. We found that this difference is also caused by the tail separation. The separation appears at a certain Mach number and remains for the higher Mach numbers. The Mach number at which the separation appears depends on the grid and turbulence model. On the other hand, the rolling moment difference is caused by the separation at the main wing juncture.