Aeroelastic flutter analysis with varying level of accuracy

Sammanfattning: Flutter prediction is a vital part of aircraft development which requires efficient and accurate analysis methods. Saab AB Aeronautics is currently using linear analysis based on the panel method and nonlinear analysis using their in-house CFD software program. These methods are in contrast to one another in terms of computing time and accuracy. There is a need to fill the gap between these methods in terms of efficiency and accuracy for future development of the current and next generation aircraft. This project will evaluate the flutter analysis methods implemented in the software programs ZAERO and ZEUS developed by Zona Technology, Inc. The handling of these software programs will be evaluated based on efficiency, accuracy and ease of use. JAS 39 Gripen was used for the analyses in this project. A new high fidelity aerodynamic model of the aircraft was developed to take advantage of the modelling capabilities implemented in the software. The effect of different modelling options such as airfoil thickness, fuselage fidelity and movable control surfaces was investigated. Finally, the accuracy of the predicted aeroelastic response was validated by comparison with previous numerical results and experimental data. Both ZAERO and ZEUS are concluded to be overall robust in their calculations and the results are in close correlation with previous analyses. The computational effectiveness is reasonable and can be further improved with some refinement of the model and solution parameters. The evaluation shows that both software programs has the potential to complement the current methods used by Saab.