Toward an Efficient Method for F-16 Limit Cycle Oscillation Prediction

Abstract

This study presents the development and validation of a computationally efficient prediction framework for the well-known nonlinear F-16 limit cycle oscillation (LCO) phenomenon. The framework relies on a simple physical working model that has been suggested and demonstrated in the past according to which LCO is primarily a flutter instability that is bounded by the existence of nonlinear structural damping (NSD), although potentially affected by nonlinear aerodynamic effects as well. In the framework developed herein, the NSD model is derived and calibrated using a novel method that simplifies the process and allows applicability of the derived NSD models for multiple aircraft download cases. Good LCO prediction capabilities are obtained using the suggested method in terms of LCO levels and trends with flight conditions, as demonstrated using four F-16 test configurations. This framework also allows several practical benefits, which makes it particularly suitable for industrial-level applications.