High Resolution Turbulence Treatment of F/A-18 Tail Buffet

Abstract

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 Reynolds-averaged Navier-Stokes turbulence models with the detached-eddy simulation hybrid approach reveals the inadequacies of Reynolds-averaged Navier-Stokes methods and the ability of detached-eddy simulation to reproduce the observed unsteadiness at these conditions. Computed vortex breakdown position and frequencies of the detached-eddy simulation method are shown to be accurate by comparison to flight-test and experimental results. Finally, comparison of the detached-eddy simulation unsteady tail pressures with flight-test tail pressures reveal the ability of the method to accurately reproduce F/A-18 tail buffet loads and its readiness for inclusion in a fluid-structure interaction method.