A Reduced Order Model for Dynamic Loads Prediction including Aerodynamic Nonlinearities

Abstract

In this paper a novel frequency domain Reduced Order Model (ROM) to compute the dynamic response to atmospheric disturbances of a free aircraft flying in the transonic regime including CFD aerodynamics is presented. It is based on correction of the unsteady Aerodynamic Influence Coefficient (AIC) matrices. First, the ROM is applied within the aerodynamic linear region where effects can be superposed using a minimum number of unsteady CFD computations and validated against results obtained by direct coupled CFD-CSM simulation. Additionally, the ROM is extended into a nonlinear region linearizing around a dynamic state instead of the usual steady state linearization. Again, results are validated against direct coupled nonlinear time domain simulations.