AIAA Paper 2004-1676. Presented at the 45th AIAA/ASME/ASCE/AHS/ASC Structure, Structural Dynamics & Materials Conference, April 19, 2004, pages 1-13. This article is in the public domain. Published by American Institute of Aeronautics and Astronautics.
NOTE: At the time of publication, the author Russell M. Cummings was on sabbatical leave from Cal Poly.
Unsteady tail loads of the F/A-18 are computed using various turbulence models at an angle of attack consistent with buffet induced by leading-edge extension vortex breakdown. Comparison of these industry standard turbulence models with the Detached Eddy Simulation (DES) hybrid RANS-LES approach reveals the inadequacies of RANS methods and the ability of DES to reproduce the observed unsteadiness at these conditions. Computed vortex breakdown position and frequencies of the DES method are shown to be accurate by comparison to flight test and experimental results. Finally, comparison of the DES unsteady tail pressures with flight-test tail pressures reveal the ability of the method to accurately reproduce F/A-18 tail buffet loads and is ready for inclusion in a fluid-structure interaction method.