Analysis of CFD Pressure Coefficients on the F-16 Wing Associated with Limit Cycle Oscillations

Abstract

*† Computational Fluid Dynamics (CFD) is used to compute unsteady pressure coefficients on the F-16 wing undergoing rigid body pitch oscillations. These pressure coefficients are analyzed in an attempt to identify how they may contribute to the onset and/or occurrence of Limit Cycle Oscillation (LCO). Interesting flow features are observed upon analyzing the unsteady pressure coefficients, vorticity magnitude iso-surfaces, and Mach=1 boundary isosurfaces. Significant differences in these flow features are ascertained between the pitch oscillation cases examined and warrant further investigation. Once pylons/launchers/stores are added in future analyses, the flow field features, such as vorticity and Mach iso-surfaces, will develop and interact differently, leading to varying pressure distributions along the wing. It is hypothesized that these flow features may interact with the structure in a way that limits the magnitude of an LCO mechanism, effectively bounding the divergent flutter.