Assessment and development of a ROM for linearized aeroelastic analyses of aerospace vehicles

In the present work,a Reduced Order Model (ROM) for aeroelastic analysis linearized around nonlinear steady solutions has been assessed and implemented to perform high-fidelity predictions, in particular for transonic flow. The ROM has been specifically adopted for identifying the unsteady aerodynamics by means of a modal-based approach. This goal has been achieved by performing a series of prescribed modal-transient boundary conditions on a Euler-based computational fluid-dynamics (CFD) code and then post-processing the input/output data in the frequency domain. A fast and efficient morphing code based on the use of Radial Basis Functions (RBF) has been introduced at this phase of the procedure to reach a wide range of applicability for significant cases with complex geometries as in the case of aeronautical and space vehicles. Flutter boundaries have been investigated by capturing the so-called transonic dip phenomenon, mainly due to compressibility and evidenced in the literature also by wind tunnel tests. Comparisons of the present results with linear lower fidelity approaches, based on potential flows, have demonstrated the capabilities of the proposed ROM. Finally, in order to show the general-purpose applicability of the proposed approach, the method has been applied to the aeroelastic analysis of a launch vehicle (LV). For this application no commercial codes for linear aeroelastic analysis are available for comparisons.