Aeroelastic stability must be maintained for the entire flight duration. Of the vast phenomena that fall under the field of aeroelasticity, flutter is the most studied and influential in terms of driving aircraft design. As such, it is the main topic of analysis of this Master Thesis. For flutter analysis, it is of critical importance to accurately model the system unsteady aerodynamics, particularly for harmonic oscillatory motion. Therefore, the aim of this Master Thesis is to study the aerodynamic accuracy of a method that uses high fidelity unsteady CFD simulations to build a linearized aerodynamic model, applicable to flows of linear nature. The unsteady aerodynamic loads obtained with the linearized aerodynamic CFD model are validated by comparing them to that of Theodorsen and unsteady OpenFOAM simulations of a harmonically oscillating 2D airfoil.
The results obtained by the linearized aerodynamic CFD model are unable to predict the unsteady air loads for oscillatory harmonic airfoil motion and therefore cannot be used to accurately predict the flutter boundary. The underlying reason for this is the fact that the current formulation of the model does not take into account the wake effects on the unsteady air loads.