CFD-based Multi-Axis Maneuver Simulation for System Identification of Flexible Transport Aircraft

A crucial part of the design and certification process of a transport aircraft is the identification of its flight mechanic stability and control characteristics. This task is typically complied with a time and cost consuming flight test campaign with multistep, one-surface-at-time inputs for each flight condition. Given the accuracy of state of the art multidisciplinary analysis methods including aerodynamics, flight dynamics, and structural dynamics, the substitution of the real flight test by numerical simulation is appropriate and promises time and cost savings. In order to obtain highly accurate simulation results only CFD methods solving the URANS equations seem adequate for the calculation of the aerodynamic forces. In this work we present an approach for the high-fidelity multidisciplinary maneuver simulation based on CFD. The goal is to generate virtual flight test data of high accuracy to be used in a subsequent system identification process which estimates the stability and control characteristics of the aircraft. A wavelet transform method is applied for the design of input signals to the primary control surfaces, where care is taken to keep the total simulation time of the maneuver as low as possible. The test case is a medium-range jet transport for which the approaches, the simulation models, as well as the results of a longitudinal and a multi-axis identification maneuver are presented and discussed.