Unsteady Aerodynamic Modeling of A Maneuvering Aircraft Using Indicial Functions

Abstract : The generation of reduced-order models for the evaluation of unsteady and nonlinear aerodynamic loads is investigated. This approach is based on Duhamels superposition integral using indicial response functions. The indicial functions are directly calculated using the results of unsteady Reynolds-averaged Navier-Stokes simulation and a grid-movement tool. Results are reported for an airfoil pitching oscillation and six freedom maneuver of an unmanned combat air vehicle configuration. The accuracy and efficiency of the ROM model are assessed by comparison of the model output with time-accurate computational fluid dynamics simulations. Results demonstrate the ROM method can produce accurate predictions for unsteady aerodynamic loads, along with the advantage that the model predictions require orders of magnitude less time than the time accurate simulation.